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Background and Purpose In breast cancer patients receiving neoadjuvant chemotherapy (NAC), the use of immediate breast reconstruction (IBR) as a breast cancer treatment option remains controversial. The Japanese breast cancer society conducted retrospective multicenter cohort study in the era of IBR, and we assessed the impact of NAC on surgical and oncological outcomes in patients underwent IBR. Methods Between January 2008 and December 2016, 473 (10.0%) breast cancer cases received NAC of 4726 cases underwent IBR after mastectomy. The clinicopathological and survival data of patients who received NAC (the NAC group) and those who did not receive NAC (the control group) were compared in terms of postoperative complications (infection, hemorrhage, seroma, dehiscence, tissue expander or implant loss, flap or skin necrosis) and oncologic safety. Results Eight-hundred forty cases had minor or major complications. NAC did not increase the risk of complications after IBR (OR 1.20; 95%CI 0.95 - 1.53; p = 0.13). Smoking (OR 1.35; 95%CI 1.14 - 1.62; p = 0.001), overweight (BMI25≤) (OR 1.94; 95%CI 1.61 - 2.35; p < 0.001), PMRT (OR 1.54; 95%CI 1.20 - 1.99; p = 0.01) increased risk of complications. At the median follow-up time of 76.5 months, 36 patient (7.6%) in the NAC group and 147 patients (3.5%) in the control group had local recurrence. 35 patient (7.4%) in the NAC group and 147 patients (2.0%) in the control group had reginal recurrence. Conclusion Immediate breast reconstruction after NAC is a safe procedure with post-operative complication profile. It can be performed safely and therefore should be considered as a strategy preferred for patients with local advanced breast cancer. Citation Format: Hiroko Nogi, Akiko ogiya, Naoto Kondo, Makoto Ishitobi, Chikako Yamauchi, Hiroki Mori, Ayaka Shimo, Kazutaka Narui, Naomi Nagura, Hirohito Seki, Shinsuke Sasada, Teruhisa Sakurai, Tadahiko Shien. Impact of neoadjuvant chemotherapy on the short- and long-term outcomes in patients who underwent immediate breast reconstruction after mastectomy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-15-09.

Chemotherapy-induced peripheral neuropathy (CIPN) is an important clinical challenge that threatens patients’ quality of life. This sub-study of the ABROAD trial investigated the influence of single nucleotide polymorphisms (SNPs) on CIPN, using genotype data from a randomized study to determine the optimal dose of a 3-week-cycle regimen of nab-paclitaxel (q3w nab-PTX) in patients with metastatic breast cancer (MBC). Patients with HER2-negative MBC were randomly assigned to three doses of q3w nab-PTX (SD: 260 mg/m2 vs. MD: 220 mg/m2 vs. LD: 180 mg/m2). Five SNPs (EPHA4-rs17348202, EPHA5-rs7349683, EPHA6-rs301927, LIMK2-rs5749248, and XKR4-rs4737264) were analyzed based on the results of a previous genome-wide association study. Per-allele SNP associations were assessed by a Cox regression to model the cumulative dose of nab-PTX up to the onset of severe or worsening sensory neuropathy. A total of 141 patients were enrolled in the parent study; 91(65%) were included in this sub-study. Worsening of CIPN was significantly greater in the cases with XKR4 AC compared to those with a homozygote AA (HR 1.86, 95%CI: 1.00001−3.46, p=0.049). There was no significant correlation of CIPN with any other SNP. A multivariate analysis showed that the cumulative dose of nab-PTX was most strongly correlated with CIPN (p

Little information is available about the clinical and pathologic characteristics of local recurrence (LR) after nipple-sparing mastectomy according to the locations of LR.This study classified 99 patients into the following two groups according to the location of LR after nipple-sparing mastectomy: nipple-areolar recurrence (NAR) group and other locations of LR (oLR) group. The study evaluated whether the location of LR was associated with disease-free survival (DFS) after LR resection.For about half of the patients (44.4 %) with NAR, the primary cancer was estrogen receptor (ER)-negative and human epidermal growth factor receptor 2 (HER2)-positive. Conversely, in most of the patients with oLR (79.2 %), the primary cancer was ER-positive and HER2-negative. Among the LR tumors, the frequency of noninvasive carcinoma in the NAR tumors was significantly higher than in the oLR tumors (51.9 % vs 4.2 %, respectively). During a median follow-up period of 46 months, the location of LR was not associated with DFS after LR. In the NAR group, the presence or absence of LR tumor invasiveness was the only factor associated with DFS. In the oLR group, age at primary surgery was the only factor associated with DFS.This multi-institutional retrospective study demonstrated that the features of NAR, such as the characteristics of the primary and recurrent tumors and the prognostic factors after LR resection, were quite different from those of oLR.

According to a recent report, a low Ki67 level after short-term preoperative hormone therapy (post-Ki67) might suggest a more favorable prognosis compared with a high post-Ki67 level in patients with hormone receptorpositive/human epidermal growth factor 2-negative (HR+/HER2-) breast cancer with high levels of Ki67. This study aimed to evaluate the pre-treatment genetic differences between these two patient groups. Forty-five luminal B-like patients were stratified into two groups, namely, a group with high (H→H) and one with low (H→L) Ki67 levels after short-term preoperative aromatase inhibitor (AI) treatment. We compared pre-treatment gene expression profiles between the two groups. In gene level analysis, there was no significant difference between the two groups by the class comparison test. In pathway analysis, five metabolism-related gene sets were significantly upregulated in the H→L group (p≤0.05). In the search for novel targets, five genes (PARP, BRCA2, FLT4, CDK6, and PDCD1LG2) showed significantly higher expression in the H→H group (p≤0.05). Several metabolism-related pathways were associated with sensitivity to AI. In the future, it will be necessary to seek out new therapeutic strategies for the poor prognostic group with high post-Ki67.

Purpose: Emojis are commonly used for daily communication and may be useful in assessing patient-reported outcomes (PROs) in breast cancer. The purpose of this study is to develop and validate an Emoji Sticker Scale (ESS) as a new PRO measurement. Methods: Eighteen original ESS items were developed from the PRO-CTCAE. In cohort one, the ESS validity and reliability were examined in patients with breast cancer, using a semi-structured five-question survey to investigate content validity. PROs with PRO-CTCAE and ESS were examined twice to determine criteria validity and test-retest reliability. In cohort two, the responsiveness of the scales were examined in patients treated with anthracycline, docetaxel, paclitaxel, and endocrine therapy. PROs with PRO-CTCAE and ESS were investigated two or three times, depending on the therapy. Results: Patients were enrolled from August 2019 to October 2020. In cohort one (n=70), most patients had no difficulties with the ESS, but 16 patients indicated that it was difficult to understand severities in the ESS. For criterion validity, Spearman rank correlation coefficients (rs) between PRO-CTCAE and ESS items were ≥0.41, except for “Decreased appetite.” For test-retest reliability, κ coefficients of the ESS were ≥0.41 for 16/18 items (88.9%). Response time was significantly shorter for the ESS than for PRO-CTCAE (ps≥0.41. Conclusion Parts of the original ESS developed from PRO-CTCAE require updating. However, this study provides a comprehensive confirmation of the validity, reliability, and responsiveness of the ESS.

Background/Aim: Currently, several ongoing prospective studies are investigating the safety of breast surgery omission in patients with breast cancer who are exceptional responders to neoadjuvant chemotherapy. However, there is little information about the preferences of these patients regarding omission of breast surgery. Patients and Methods: We conducted a questionnaire survey to assess preferences regarding omission of breast surgery among patients with breast cancer who had human epidermal growth factor receptor 2-positive or estrogen receptor-negative tumors and good clinical response after neoadjuvant chemotherapy. Patients’ estimation of the risk of ipsilateral breast tumor recurrence (IBTR) after definitive surgery or breast surgery omission was also assessed. Results: Of 93 patients, only 22 (23.7%) said they would omit breast surgery. Under the scenario of omitting breast surgery, the 5-year IBTR rate estimated by patients who said they would omit breast surgery was significantly lower (median, 10%) than the rate estimated by patients who preferred undergoing definitive surgery (median, 30%) (p=0.017). Conclusion: The proportion of our surveyed patients who were willing to omit breast surgery was low. Patients who said they preferred to omit breast surgery overestimated the 5-year IBTR risk.

Japanese women have the highest life expectancy in the world and breast cancer is the most prevalent cancer among them. However, little data are available to support the evidence-based clinical management due to the fact that older adults are commonly excluded from most clinical trials. In Japan the rate of other cause of death in older patient was about a half, then we should consider whether or not breast cancer may affect the patient’s life expectancy to avoid either overtreatment or undertreatment. Although management principles in older patients may be similar with those of younger age, these differences would be caused by relatively short life expectancy, some comorbidity, drug interactions and low functional status. Then, their treatment needs to be individualized. To this end, employing a comprehensive geriatric assessment may be advantageous, which enables to evaluate patient vulnerability from several different aspects, to predict adverse events of chemotherapy and to identify geriatric problems in advance so that extra support and modified treatment can be provided. Before treatment we should assess the patient’s goals and values regarding the management of the cancer, especially on balancing survival benefit with immediate quality of life impairment due to anti-cancer therapy. In Japan Clinical Oncology Group (JCOG) , a randomized controlled trial for older patients with advanced stage HER2-positive breast cancer is ongoing as an inferiority design including geriatric assessment (JCOG1607, HARB TEA study). Best practice, current management and how to approach decision making in older patients with breast cancer are summarized.

Background In 2019, the Japanese government has introduced the economic valuation to healthcare system. However, the threshold for determining cost-effectiveness-analysis has yet to be adequately studied. Therefore, we have designed a study to examine the financial value of “life” and “health” based on willingness-to-pay (WTP) considered by patients with primary and metastatic breast cancer (PBC and MBC) in Japan. Methods This study is conducted by forty-five hospitals under the Breast Cancer Study Group of Japan Clinical Oncology Group (JCOG). In the preliminary study, 168 patients (84 patients with PBC and 84 patients with MBC) from 20 to 79 years of age paying medical costs were examined their WTP for setting up the dichotomous-choice method survey form for using in the main study. Virtual scenario-specific treatments to avoid the recurrence and death of breast cancer for one year for PBC patients, and to prolong the survival period for one year for the patients with MBC were presented. The patients were evaluated how much money would pay to receive the treatment in a self-written answer and the amount of WTP that would be presented in the main study was determined. In the main study, 1,620 patients (810 patients with PBC and 810 patients with MBC) were surveyed to their WTP for hypothetical scenarios using the dichotomous-choice method survey form. With the two-step dichotomous-choice method, if the first stage response was yes, a higher amount was displayed for the second stage. If the first stage response was no, a lower amount was shown for the second stage. For the main analysis, the acceptance probability curve was calculated using the parametric method. The calculation was based on the obtained responses and median WTP, which was determined by calculating the amount at which the acceptance probability curve is at 50%. The obtained amount was converted to WTP per one QALY based on the displayed question content. Results Completed surveys were collected from 716 PBC patients (88.4%) and 702 patients (86.7%). Based on the preliminary study, the amount of WTP offering in the first stage was set 5 million yen (JPY) (50,000 USD), and offering in the second stage was 7 million JPY (70,000 USD) for those who responded accepting the scenario treatment and 3 million JPY (30,000 USD) for those who responded refusing. We obtained point estimates of WTP for each virtual scenario treatments. The WTP of the two hypothetical scenarios for PBC patients were as follows; scenario 1) the treatment to gain one year without recurrence: 2.06 million JPY (20,600 USD), scenario 2) the treatment that reduces risk of recurrence by 40%: 2.40 million JPY (24,000 USD). The WTP of the two hypothetical scenarios for MBC patients were as follows; scenario 3) the treatment that can prolong survival for one year in current health condition: 2.81 million JPY (28,100 USD), scenario 4) the treatment that can prolong survival by one year in the health condition before having breast cancer: 2.92 million JPY (29,200 USD). Conclusion We created hypothetical 1-quality-adjusted survival year (QALY) scenarios for breast cancer patients with different disease status and validated them using the contingent valuation method. Our results demonstrate that WTP per 1QALY varies with the disease status of breast cancer. Therefore, we conclude that we cannot simply use a uniform threshold when examining the cost-effectiveness of medical interventions in breast cancer as a unit of cost/QALY. Citation Format: Tsuguo Iwatani, Fumikata Hara, Tadahiko Shien, Masato Takahashi, Norikazu Masuda, Yasuaki Sagara, Keita Sasaki, Junki Mizusawa, Haruhiko Fukuda, Takaru Shiroiwa, Hiroji Iwata. Estimation of willingness-to-pay for breast cancer treatments through contingent valuation method in Japanese breast cancer patients (JCOG1709A): The main study findings [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-16-04.

Background: Hormone receptor (HR)-positive HER2-negative breast cancers have a lower tumor mutation burden than other types of cancer and triple-negative breast cancer, resulting in relatively low immunogenicity. It is also known that estrogen suppressively regulates immunity through regulatory T cells in the tumor microenvironment. Therefore, the development of immunotherapy in HR-positive and HER2-negative breast cancer is a challenging issues. Anti-VEGF therapy has been shown to improve antigen presentation, local migration of cytotoxic T lymphocytes, and suppressive tumor microenvironment in preclinical and clinical studies of various cancers. Anti-VEGF therapy can be hypothesized to modulate immunotherapy. Methods: JCOG1919E (AMBITION) is a randomized, multicenter, open-label, phase III trial to evaluate efficacy and safety of bevacizumab and paclitaxel in combination with atezolizumab (BEV+PTX+ATZ) comparing to bevacizumab and paclitaxel (BEV+PTX) in patients with HR-positive HER2 negative locally advanced or metastatic breast cancer. The key eligibility criteria are as follows: 1) ECOG PS 0-2, 2) ER and/or PgR positive and HER2-negative breast cancer, 3) endocrine resistance or life-threatening disease, 4) measurable disease, 5) centrally confirmed programmed death-ligand 1 (PD-L1) status on tumor-infiltrating immune cells, 6) no prior chemotherapy for locally advanced or metastatic breast cancer, 7) adequate organ function. Patients will be randomized (staratified by recurrence/de novo, liver metastasis, or PD-L1 status) in a 1:1 ratio, to BEV+PTX arm or BEV+PTX+ATZ arm. Patients in arm A receive PTX (90 mg/m2/day, days 1, 8 and 15, iv) and BEV (10 mg/kg/day, days 1 and 15, iv) on a 28-day cycle. Patients in arm B receive PTX and BEV plus ATZ (840 mg/body/day, days 1 and 15, iv). Treatment in both arms is continued until disease progression or unacceptable toxicity. The primary endpoint is progression-free survival (PFS) assessed by investigators. The secondary endpoints include overall survival, PFS assessed by blinded independent central review, response rate, adverse events, PFS (PD-L1 positive), and OS (PD-L1 positive). We assumed a median PFS of 16 months in BEV+PTX+ATZ arm and 11 months in BEV+PTX arm. The planned sample size was calculated as a total of 280 patients (140 patients per arm) with a one-sided alpha of 2.5%, power of 80%, an accrual period of 2.5 years, and a follow-up period of 2 years. Translational research also will be conducted accompanying with this trial. Patient accrual was started in January 29, 2021 and 37 patients were enrolled by June 18, 2021. Safety of patients in this study is being monitored by IDMC. For further information on this trial, visit ClinicalTrials.gov (NCT04732598). Citation Format: Fumikata Hara, Makiko Ono, Shigehisa Kitano, Shigehira Saji, Akihiko Shimomura, Takashi Yamanaka, Takayuki Kadoya, Mitsuya Ito, Hiroko Bando, Hiroyuki Yasojima, Keita Sasaki, Tomoko Kataoka, Tadahiko Shien, Kan Yonemori, Hiroji Iwata. A randomized controlled phase III study of bevacizumab and paclitaxel in combination with atezolizumab as a treatment for patients with locally advanced or metastatic hormone receptor-positive HER2 negative breast cancer: JCOG1919E/AMBITION study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT1-18-01.

One barrier to the widespread use of breast reconstruction (BR) is physicians' perception that BR adversely affects breast cancer prognosis. However, there is limited information regarding physicians' understanding of the impact of BR on patient prognosis and which physicians have misunderstandings about BR.We conducted an e-mail survey regarding the impact of BR on the prognosis of patients with breast cancer among members of the Japanese Breast Cancer Society.Of 369 respondents, 99 (27%) said that they believe BR affects patient prognosis. Female respondents and those who treat fewer new breast cancer patients per year were more likely to state that they believe BR affects patient prognosis (P = 0.006 and 0.007). Respondents who believed that BR affects patient prognosis underestimated 5-year overall survival rates in patients who receive BR and subsequently have local or regional recurrence in different sites.Our survey demonstrated that a quarter of respondents believe that BR affects patient prognosis and underestimate survival rates in patients who receive BR and have subsequent local or regional recurrence. Because of the lack of evidence regarding the impact of BR on patient prognosis, educating physicians by providing accurate knowledge regarding BR and patient prognosis is highly recommended.

The standard first-line treatment for patients with human epidermal growth factor 2-positive metastatic breast cancer is a combination therapy of trastuzumab, pertuzumab and docetaxel, and the standard second-line treatment is trastuzumab emtansine. However, it may be difficult for the elderly to maintain sufficient intensity of treatment due to severe adverse events of trastuzumab, pertuzumab and docetaxel. The aim of this trial is to confirm the non-inferiority of trastuzumab emtansine over trastuzumab, pertuzumab and docetaxel in terms of overall survival in elderly (65-year-old or more) patients with human epidermal growth factor 2-positive metastatic breast cancer. If improved overall survival and fewer toxicities are observed, trastuzumab emtansine may be a feasible new standard first-line treatment for elderly patients with human epidermal growth factor 2-positive metastatic breast cancer. A planned total 330 patients will be enrolled from 45 institutions over 6.5 years. This trial has been registered in the UMIN Clinical Trials Registry as UMIN000030783 [http://www.umin.ac.jp/ctr/index.htm].

Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment that mediate resistance of cancer cells to anticancer drugs. Tranilast is an antiallergic drug that suppresses the release of cytokines from various inflammatory cells. In this study, we investigated the inhibitory effect of tranilast on the interactions between non-small cell lung cancer (NSCLC) cells and the CAFs in the tumor microenvironment. Three EGFR-mutant NSCLC cell lines, two KRAS-mutant cell lines, and three CAFs derived from NSCLC patients were used. To mimic the tumor microenvironment, the NSCLC cells were cocultured with the CAFs in vitro, and the molecular profiles and sensitivity to molecular targeted therapy were assessed. Crosstalk between NSCLC cells and CAFs induced multiple biological effects on the NSCLC cells both in vivo and in vitro, including activation of the STAT3 signaling pathway, promotion of xenograft tumor growth, induction of epithelial-mesenchymal transition (EMT), and acquisition of resistance to molecular-targeted therapy, including EGFR-mutant NSCLC cells to osimertinib and of KRAS-mutant NSCLC cells to selumetinib. Treatment with tranilast led to inhibition of IL-6 secretion from the CAFs, which, in turn, resulted in inhibition of CAF-induced phospho-STAT3 upregulation. Tranilast also inhibited CAF-induced EMT in the NSCLC cells. Finally, combined administration of tranilast with molecular-targeted therapy reversed the CAF-mediated resistance of the NSCLC cells to the molecular-targeted drugs, both in vitro and in vivo. Our results showed that combined administration of tranilast with molecular-targeted therapy is a possible new treatment strategy to overcome drug resistance caused by cancer-CAF interaction.

Objective This study examined the pharmacokinetics, safety and anti-tumor activity of docetaxel at a dose of 100 mg/m2 in Japanese patients with advanced or recurrent breast cancer. Methods Japanese patients with advanced or recurrent breast cancer received docetaxel at a dose of 100 mg/m2 intravenously every three weeks. The pharmacokinetics were assessed during the first cycle. The patients were allowed to receive supportive care drugs based on the indications and dosages in Japan. Results Six eligible patients aged 39-65 years old and 27 treatment cycles were analyzed. All patients experienced one or more adverse events (AEs). The common AEs were neutropenia, thrombocytopenia, alopecia, rash, diarrhea, neuropathy (sensory), fatigue, nausea, fever, hypoalbuminemia, alanine transaminase (ALT) increased, constipation, and taste alteration. Grade 3 or 4 AEs included neutropenia, leukopenia, anemia, lymphopenia, decreased appetite, γ-glutamyl transpeptidase (GTP) increased, aspartate transaminase (AST) increased, ALT increased, hypertension and cellulitis which were all reversible. There were no cases of febrile neutropenia, serious AEs or deaths. The median number of cycles was six. Dose reductions were not observed and most cycles were administered at their intended doses. No complete response and three partial responses were observed in four assessable patients with evaluable lesions. The maximum concentration and area under the blood concentration-time curve were 3,417.5 ng/mL and 4.35 μg・hr/mL (mean), respectively. Conclusion Docetaxel at a dose of 100 mg/m2 was tolerable with acceptable safety profiles and effective for Japanese patients with advanced or recurrent breast cancer with appropriate supportive therapies, and pharmacokinetic (PK) profiles which corresponded approximately with the findings of previous clinical studies.

In April 2016, the Japanese government introduced health technology assessment as a response to rising medical expenses due to ‘medical innovation’. This study investigates how Japanese breast cancer patients who received treatment in Japan consider the financial value (willingness-to-pay; WTP) for their life and health by using the contingent valuation method (CVM) prospectively. First, 168 patients (84 primary breast cancer patients and 84 metastatic breast cancer patients) were pre-examined their WTP with dichotomous-choice method survey form. Next, 1,596 patients (798 primary breast cancer patients and 798 metastatic breast cancer patients) will be surveyed to their WTP for hypothetical scenarios in CVM. Based on our results, we will construct an evaluation axis from the patients’ viewpoint for the cost-effectiveness of clinical trials to establish standard treatments for breast cancer. We believe this research can contribute to create a meaningful healthcare system for patients, clinicians, industries, and healthcare policymakers., This study investigated how Japanese breast cancer patients who received treatment in Japan consider the willingness-to-pay for their life and health by using the contingent valuation method prospectively.

Background: The surgical treatment is the standard therapy for early breast cancer (EBC) after primary systemic therapy (PST). In more than half of HER2 positive (HER2(+)) breast cancer, pathological complete response (pCR) is achieved by PST with HER2 inhibitors and chemotherapy. However, non-surgical therapy is not an option for EBC with cCR after PST because of little evidence. We planned a single-arm confirmatory study to evaluate the efficacy and safety of the non-surgical therapy for HER2(+) EBC with cCR after PST. Methods: The key eligibility criteria are as follows: 1) Histologically confirmed as invasive ductal carcinoma of the breast, HER2(+). 2) cT1-2, N0, M0 (UICC 8th). 3) No ipsilateral BC. 4) Women aged 20-74 years. 5) ECOG performance status 0 or 1. 6) Adequate hematologic and organ function. 7) Ejection fraction as cardiac function is over 50%. 8) Written informed consent. HER2 inhibitors (trastuzumab and pertuzumab) and cytotoxic drugs as PST are administered to all patients (pts). After completion of PST, cCR is diagnosed by breast imaging and physical examination. cCR is defined as 1) Not palpable breast mass by physical examination, 2) No enhanced breast mass by enhanced MRI, and 3) No breast mass by ultrasonography. 4) For hormonal receptor (+) EBC, needle biopsy after PST must be done to evaluate the pCR. After a diagnosis of cCR, conventional radiotherapy for whole breast and boost radiation for tumor bed is mandatory, followed by pertuzumab and trastuzumab every 3 weeks for 9 months. In non-cCR cases, surgical resection is performed and adjuvant therapy is not specified. The primary endpoint is a distant metastasis-free survival (DMFS) at 3 years, the secondary endpoints are DFS, OS, RFS, the proportion of local recurrence, and cosmetics outcome. Given that the threshold and expected DMFS at 3-year is 93% and 98% with a significance level of 2.5% (one-sided) and 80% power, 170 cCR cases are required. Assuming half of the HER2 pts reach cCR, 350 pts are required as the sample size started PST. Enrollment launched in January 2020, and 260 pts are enrolled as of July 12, 2022. This clinical trial has been registered at the Japan Registry of Clinical Trials as jRCTs031190129 and conducted by the Japan Clinical Oncology Group (JCOG) Breast Cancer Study Group under a public fund (National Cancer Center Research and Development Fund). Citation Format: Tomomi Fujisawa, Hideo Shigematsu, Tadahiko Shien, Hiroji Iwata, Keita Sasaki, Taro Shibata. A single-arm confirmatory study to evaluate the efficacy of non-surgical therapy for HER2 positive early breast cancer with clinical complete response after primary systemic therapy: (JCOG1806) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-01-01.

Background We conducted a prospective study with the intention to omit surgery for patients with ductal carcinoma in situ (DCIS) of the breast. We aimed to identify clinicopathological predictors of postoperative upstaging to invasive ductal carcinoma (IDC) in patients preoperatively diagnosed with DCIS. Patients and methods We retrospectively analyzed patients with DCIS diagnosed through biopsy between April 1, 2010 and December 31, 2014, from 16 institutions. Clinical, radiological, and histological variables were collected from medical records. Results We identified 2,293 patients diagnosed with DCIS through biopsy, including 1,663 DCIS (72.5%) cases and 630 IDC (27.5%) cases. In multivariate analysis, the presence of a palpable mass (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.2–2.6), mammography findings (≥ category 4; OR 1.8; 95% CI 1.2–2.6), mass formations on ultrasonography (OR 1.8; 95% CI 1.2–2.5), and tumor size on MRI (> 20 mm; OR 1.7; 95% CI 1.2–2.4) were independent predictors of IDC. Among patients with a tumor size on MRI of ≤ 20 mm, the possibility of postoperative upstaging to IDC was 22.1%. Among the 258 patients with non-palpable mass, nuclear grade 1/2, and positive for estrogen receptor, the possibility was 18.1%, even if the upper limit of the tumor size on MRI was raised to ≤ 40 mm. Conclusion We identified four independent predictive factors of upstaging to IDC after surgery among patients with DCIS diagnosed by biopsy. The combined use of various predictors of IDC reduces the possibility of postoperative upstaging to IDC, even if the tumor size on MRI is larger than 20 mm.

BackgroundIn 2019, the Japanese government has decided to introduce the economic valuation to healthcare system. However, the threshold for determining cost-effectiveness-analysis has yet to be adequately studied. Therefore, we have designed a study to examine the financial value of “life” and “health” based on willingness-to-pay (WTP) considered by approximately 1,800 patients with primary and metastatic breast cancer (PBC and MBC) in Japan. Preliminary study has been conducted to set the amount of WTP prior to the main study. Methods This study is conducted by six leading hospitals under the Breast Cancer Study Group of Japan Clinical Oncology Group (JCOG). 168 patients (84 patients with PBC and 84 patients with MBC) from 20 to 79 years of age paying medical costs were examined their WTP for setting up the dichotomous-choice method survey form. Virtual scenario-specific treatments to avoid the recurrence and death of breast cancer for one year for PBC patients, and to prolong the survival period for one year for the patients with MBC were presented. The patients were evaluated how much money would pay to receive the treatment in a self-written answer. The amount of WTP that will be presented in the main study was determined by calculating the median price from these responses based on the protocol. In addition, we conducted surveys of quality-of-life by EQ-5D-5L, social background on patients, and of breast cancer medical condition on doctors. Results Completed surveys were collected from 166 doctors (98.8%) and 139 patients (82.7%). The range of the amount of WTP for scenario-specific treatments among the patients with the patients with PBC was from 0 to 5 million Japanese yen (JPY) (50,000 USD), and among the patients with MBC was from 0 to 10 million JPY (100,000 USD). In accordance with the criteria set forth in advance in the protocol, the amount of WTP that will be presented in the main study was set at 5 million JPY in both PBC and MBC patients. Conclusion We have fixed the cost that will be presented in the main study based on the findings of our preliminary study. The main study will commence around September 2020. Citation Format: Tsuguo Iwatani, Fumikata Hara, Tadahiko Shien, Masato Takahashi, Norikazu Masuda, Hiroyuki Yasojima, Yasuaki Sagara, Tomonori Mizutani, Keita Sasaki, Kenichi Nakamura, Haruhiko Fukuda, Takaru Shiroiwa, Hiroji Iwata. Estimation of willingness-to-pay for breast cancer treatments through contingent valuation method in Japanese breast cancer patients (JCOG1709A); preliminary study findings [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-57.

Background Advance care planning (ACP) is a process that supports adults in understanding and sharing their personal values, life goals, and preferences regarding future medical care. We examined the current status of ACP and end‐of‐life (EOL) communication between oncologists and patients with metastatic breast cancer. Materials and Methods We conducted a survey among 41 institutions that specialize in oncology by using an online tool in October 2019. Participants (118 physicians) from 38 institutions completed a 39‐item questionnaire that measured facility type and function; physicians’ background and clinical approach, education about EOL communication, and understanding about ACP; and the current situation of ACP and EOL discussions. Results Ninety‐eight responses concerning physicians’ engagement in ACP with patients were obtained. Seventy‐one (72%) answered that they had engaged in ACP. Among these, 23 (33%) physicians used a structured format to facilitate the conversation in their institutions, and only 6 (8%) settled triggers or sentinel events for the initiation of ACP. In the multivariable analysis, only the opportunity to learn communication skills was associated with physicians’ engagement with ACP (odds ratio: 2.8, 95% confidence interval: 1.1–7.0). The frequency and timing of communication about ACP and EOL care with patients substantially varied among the oncologists. Communication about patients’ life expectancy was less frequent compared with other topics. Conclusion The opportunity to improve EOL communication skills promoted physicians’ engagement with ACP among patients with metastatic/advanced breast cancer. However, there were still substantial variabilities in the method, frequency, and timing of ACP and EOL communication among the oncologists. Implications for Practice This study found that the opportunity to improve end‐of‐life (EOL) communication skills promoted physicians’ engagement in advance care planning (ACP) among patients with metastatic/advanced breast cancer. All oncologists who treat said patients are encouraged to participate in effective education programs concerning EOL communication skills. In clinical practice, there are substantial variabilities in the method, frequency, and timing of ACP and EOL communication among oncologists. As recommended in several clinical guidelines, the authors suggest a system that identifies patients who require conversations about their care goals, a structured format to facilitate the conversations, and continuous measurement for improving EOL care and treatment., The purpose of advance care planning is to enable individuals to make plans about their future health care and improve discussions about end‐of‐life care and treatment. This article examines the current status of advance care planning for patients with advanced metastatic breast cancer to determine factors associated with physician engagement in institutions that specialize in oncology.

Over the past 10 years, immunotherapy with immune checkpoint inhibitors has revolutionized the management of various cancers. However, immunotherapy in breast cancer has not been successful. Breast cancer has long been recognized as an immunologically ‘cold’ tumor, although a higher frequency of tumor-infiltrating lymphocytes present in certain subtypes and an association between tumor-infiltrating lymphocytes and favorable prognosis have been reported. In March 2019, the combination of atezolizumab and nanoparticle albumin-bound paclitaxel was granted accelerated approval in the United States for the treatment of programmed death-ligand 1-positive advanced or metastatic triple-negative breast cancer. This finally opened the door for immune checkpoint blockade therapy for breast cancer. Several clinical trials have been conducted using different combinations of immune checkpoint inhibitors and chemotherapy or targeted agents in various treatment settings for metastatic breast cancer and early-stage breast cancer. In this review, we summarize recent advances in immune checkpoint blockade therapy and predictive biomarkers in breast cancer.

BackgroundPrevious study results have suggested that local treatment of isolated lung metastases, may be beneficial and increase overall survival (OS) in highly selected patients. However, these were all retrospective studies. We designed this prospective cohort study to investigate the therapeutic and diagnostic clinical situation of oligometastatic breast cancer in the lung, as well as the prognosis outcomes of patients with this disease.MethodsWe enrolled patients with less than 3 lung nodules which suspected as oligometastases after curative breast cancer surgery. Treatments, including local and systemic therapy, were choice by each physician. The primary outcome was OS of patients with oligometastasis of breast cancer detected in the lung and secondary outcomes were the efficacy and safety of surgery for lung oligometastases. The study was in accordance with the relevant national/institutional guidelinesResultsBetween May 2015 and May 2019, 14 patients were enrolled at 5 centers. Resection of lung nodules (metastasectomy) was performed 11 (78.6%) of 14 patients and one was diagnosed with primary lung cancer. Metastasectomy were all performed employing video-assisted thoracic surgery (VATS) and achieved complete resection without perioperative complication. Systemic therapies such as chemotherapy, as well as endocrine and molecular target therapies were administered to all patients except one who declined all treatments offered. The respective 3-year and 5-year OS rates of patients with lung oligometastases were 91.6% and 81.5%. Progression events occurred in 6 patients: 3 (30%) with and 3 (100%) without metastasectomy. Whereas 2 of 10 patients with metastasectomy survived 5 years without progression, progression events occurred all patients without metastasectomy within 1 year.ConclusionLung metastasectomy was worthwhile as a diagnostic evaluation and possibly provide long-term benefit in some patients. Phase 3 trials might be required to provide definitive evidence and to provide criteria for selecting patients. Trial registrationThis study was approved by the Institutional Review Board (IRB No. 960) of the Okayama University Hospital, Okayama, Japan, and was registered in the clinical trials database UMIN (UMIN000016999) on 31 March 2015. Written informed consent was obtained from all enrolled patients.

Breast cancer is highly sensitive to systemic therapy. High probability of pathological complete response suggests a clinical question that omitting surgery is an effective alternative to surgery in breast cancer showing clinical complete response to primary systemic therapy. However, the validity of omitting surgery for early breast cancer after primary systemic therapy has not been sufficiently established; thus, even if pathological complete response is expected in patients showing clinical complete response, excision of the primary tumor site remains the standard treatment of breast cancer. Inappropriate omitting surgery increases the incidence of local recurrence, which can be the risk of a subsequent distant metastasis and reduced overall survival. To achieve acceptable local control rate, omitting surgery should be investigated in patients with early breast cancer where a high percentage of pathological complete response, a high concordance rate between clinical complete response and pathological complete response and an acceptable local control rate are expected. This review presents concept and ongoing clinical trials for omitting surgery for patients with breast cancer showing clinical complete response to primary systemic therapy.

Introduction Patients with residual disease usually have a poor prognosis after neoadjuvant chemotherapy for breast cancer. The aim of this study was to explore therapeutic targets and potential additional adjuvant treatments for patients with residual disease after standard neoadjuvant chemotherapy. Patients and Methods We retrieved publicly available complementary DNA microarray data from 399 human epidermal growth factor receptor 2 (HER2)-negative primary breast cancer samples from patients who underwent standard neoadjuvant chemotherapy. We analyzed the messenger RNA (mRNA) expression levels of key breast cancer markers and therapeutic target genes according to residual cancer burden (RCB) classification: RCB-0/I, RCB-II, and RCB-III. Results Among hormone receptor–positive samples, there were more luminal A tumors by PAM50 (Prediction Analysis of Microarray 50 [Prosigna], aka Prosigna Breast Cancer Prognostic Gene Signature Assay) in RCB-III than in RCB-0/I and RCB-II (P < .01). The mRNA expressions of ESR1 and PGR were significantly higher, and that of MKI67 was lower in RCB-II and RCB-III than in RCB-0/I. The mRNA expression of cyclin D1 was up-regulated in RCB-III and that of CDKN2A was down-regulated in RCB-III (P = .027 and < .01). Among triple-negative (TN) samples, RCB-III had higher clinical stage and more lymph node–positive samples than RCB-0/1 and RCB-II (P < .01). In both subtypes, VEGF-C expression was significantly higher in RCB-III than in RCB-0/I and RCB-II. Conclusion In hormone receptor–positive breast cancer, biological features such as luminal A were associated with RCB; this trend was not observed in TN breast cancer. Further, some targeted therapies should be tested as new strategies after standard neoadjuvant chemotherapy in future clinical trials.

Background In hormone receptor (HR)-positive / human epidermal growth factor receptor 2 (HER2)-negative breast cancers, high Ki-67 predicts poor prognosis. Recently, it has been reported that among breast cancers with high Ki-67, low Ki-67 after short-term preoperative hormone therapy (post Ki-67) might predict favorable prognosis compared to high post Ki-67 (SABCS 2017). However, the differences in gene expression profiling of breast cancers between high and low post Ki-67 among high Ki-67 before treatment are unclear. Therefore, this study aimed to clarify genetic differences in two groups and to explore novel therapeutic targets for the poor prognostic group after the treatment. Methods Seventy-seven patients with primary HR-positive / HER2-negative breast cancer who received an aromatase inhibitor for 2 weeks [NCBI Gene Expression Omnibus repository GSE80077:19 cases, GSE20181:58 cases] were enrolled in this study. Forty-five patients with high pre Ki-67 among them were stratified into two groups, high (H→H) and low (H→L) post Ki-67 after short-term preoperative hormone therapy. We compared gene expression profiling in two groups about the followings. 1) 3 genes (ESR1, PGR and ERBB2) related to classical clinical treatment strategy of breast cancer, immune- and inflammatory-related genes 2) 178 pathways (gene set analysis) 3) 41 genes that are targeted by FDA-approved drugs or have been investigated with clinical trials as molecular target agents for various malignant tumors including breast cancer Results 1) TNF that is inflammatory-related gene were significantly overexpressed in H→L group (P=0.021). However, 3 genes related to clinical treatment of breast cancer and immune-related genes expression had no significant difference between two groups. 2) 5 gene sets (Tryptophan metabolism, Propanoate metabolism, beta-Alanine metabolism, SNARE interactions in vesicular transport and Nucleotide excision repair) were significantly upregulated in H→L group. (P ≤ 0.005) 3) 5 targeted genes (PARP, BRCA2, FLT4, CDK6 and PDCD1LG2) were significantly overexpressed in H→H group (P ≤ 0.05). Conclusions There were different gene expression and biological processes in two groups stratified by post-Ki67. In the future, it is necessary to seek new therapeutic strategies for poor prognostic group with high post-Ki67 in considerations of these differences. Citation Format: Yukiko Kajiwara, Takayuki Iwamoto, Yusuke Otani, Miwa Fujihara, Yoko Suzuki, Minami Hatono, Takahiro Tsukioki, Kengo Kawada, Mariko Kochi, Hirokuni Ikeda, Tadahiko Shien, Naruto Taira, Hiroyoshi Doihara. Gene expression profiling of breast cancers between high and low Ki-67 after short-term preoperative hormone therapy among hormone receptor-positive / human epidermal growth factor receptor 2-negative breast cancers with high Ki-67 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-13-04.

Background: Medical expenses are on an increasing trend due to "medical innovation". The Japanese government introduced health technology assessment (HTA) in April 2016. HTA is the systematic evaluation process of scientific value, economic, social and ethical issues related to medical technology with fair and robust methods while ensuring transparency. Two achievements are expected in our research. First, we establish the evaluation standard for the interpretation of the results of cost-effectiveness analysis (CEA) of clinical trials for a standard treatment for breast cancer. Next, we can re-evaluate the HTA's decision making based on the viewpoint of general Japanese population from the perspective of cancer patients. We believe this research can contribute to the creation of a healthcare system that is meaningful to patients, clinicians, industries, and healthcare policymakers. Specific Aims: The aim of this study is to prove how Japanese breast cancer patients who received treatment in Japan consider the financial value (willingness to pay; WTP) for their life and health by using the Contingent Valuation Method (CVM), prospectively. Based on our results, we will construct an evaluation axis from patients’ viewpoint for the cost effectiveness of clinical trials to establish standard treatments for breast cancer. Key Eligibility Criteria: For Japanese breast cancer patients aged 20 to 79 who meet the followings. Unilateral breast cancer patients who fulfill either i) or ii) below i) Primary breast cancer of clinical stage 0 through III for which surgery and/ or chemotherapy and / or radiotherapy has been completed as initial treatment and that is currently undergoing regular follow-up observations or postoperative endocrine therapy. ii) Undergoing endocrine therapy or first-line through third-line chemotherapy for metastatic or recurrent cancer at least 2 months. Trial Design: This study will be conducted by the Breast Cancer Study Group of the Japan Clinical Oncology Group (JCOG). We will investigate WTP for hypothetical scenarios for primary breast cancer patients (PBC) and metastatic breast cancer patients (MBC), using a two-step dichotomous-choice method in CVM. For PBC, we will evaluate the monetary value of the prevention of recurrent cancer. Therefore, to investigate WTP, we will present hypothetical new treatments for preventing breast cancer death to these patients. In MBC, new treatments for extending survival time is presented as hypothetical scenarios and the patients’ WTP is investigated. Statistical Methods: Questionnaire data that is returned by 4 weeks (postmark deadline) after enrollment is completed at the facility and will be considered valid and analyzed. While the WTP amounts of individual responders are not clarified with the two-step dichotomous-choice method, analyses will proceed considering the obtained responses as follows. With the two-step dichotomous-choice method, if the first stage response is yes, a higher amount will be displayed for the second stage. If the first stage response is no, a lower amount will be shown for the second stage. Target Accrual: The study will be conducted in two stages. First, 168 patients (84 patients with PBC and 84 patients with MBC) will be examined to determine their WTP for setting up the dichotomous-choice method survey form. Next, 1,596 patients (798 patients with PBC and 798 patients with MBC) will be surveyed on their WTP for hypothetical scenarios in CVM. Approximately 1800 patients with primary breast cancer and stable metastatic breast cancer are enrolled. Contact information for people with a specific interest in the trial: Tsuguo Iwatani, MD, PhD. Department of Breast Surgery, National Cancer Center Hospital East tiwatani@east.ncc.go.jp Citation Format: Tsuguo Iwatani, Fumikata Hara, Hiroji Iwata, Tadahiko Shien, Takashi Hojo, Yasuaki Sagara, Norikazu Masuda, Masato Takahashi, Shigehira Saji, Tomomi Fujisawa, Naoto Kondo, Akihiko Shimomura. Estimation of willingness-to-pay for breast cancer treatments through contingent valuation method in Japanese breast cancer patients (JCOG1709A) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT3-13-01.

Background: Patient reported outcomes (PROs) have been increasingly important in breast cancer treatment. The questionnaires to evaluate PROs require high response compliance, simplicity, and friendliness. Recently, the communication with Emojis has become friendliness because of the development of social networking services and electronic devices. Therefore, we developed the Emoji scale, a novel indicator to evaluate PROs. Furthermore, two-step validation pilot studies were planned to examine the reliability of the Emoji scale for breast cancer patients at a single center. Pilot 1(Step 1) Aims: To evaluate the content validity (the primary endpoint), concurrent validity and test retest reliability of the Emoji scales (secondary endpoints). Eligibility criteria: (1) Patients with stage 0-III breast cancer. (2) Patients who have been over 1 year since the end of the initial treatment such as surgery, chemotherapy, and radiation therapy or (3) hormone receptor positive patients who have been over 1 year from the start of the endocrine therapy. (4) Patients aged >20 years who understand Japanese. Methods: The participants will complete the PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE) and Emoji scale questionnaires regarding 18 cancer related symptoms twice. First, both questionnaires will be completed in a consulting room while the staff will track the time required for completion of each questionnaire. Thereafter, the patients will be asked if there are any difficult or confused items. Second, both questionnaires will be completed again at home 7 days later. The number of planned participants is 100. Statistical analyses: Content validity will be evaluated by categorizing the comments from participants, and the nature of problems will be determined. The correlation coefficient between the PRO-CTCAE and Emoji scale scores will evaluate the concurrent validity. For the test-retest reliability, the kappa statistic between each scale at different time will be used. We will compare the time required for completion with using the t-test. Pilot 2(Step2) Aims: To evaluate the responsiveness (the primary endpoint), the effect size, the concurrent validity and comparison of the average score between participants with high and low Performance Status. (the secondary endpoints). Eligibility criteria: (1) Patients with stage 0-IV breast cancer who are scheduled to start chemotherapy or endocrine therapy. (2) Patients aged >20 years who understand Japanese. Methods: The participants will complete both the PRO-CTCAE and Emoji scales before they start a new breast cancer treatment (T1). Those will comprise chemotherapy (Cohort A: anthracycline based regimens, Cohort B: docetaxel based regimens, Cohort C: paclitaxel based regimens, Cohort E: eribulin based regimens, and Cohort F: capecitabine/S1 based regimens) or endocrine therapy (Cohort D: tamoxifen/aromatase inhibitor). After several weeks, the participants will complete the same questionnaires again (T2). This time interval will depend on the therapy, and some participants will be complete once again the questionnaires (T3) a few weeks after T2. The number of planned participants is 30 in each cohort. Statistical analyses: Responsiveness will be evaluated by the correlation coefficient between the change from the baseline to second or third score of each scale. The effect size of the Emoji scale will be determined by the difference between the average score of the second or third and that of the baseline divided by the standard deviation of the baseline score. The correlation coefficient for each scale at each time will evaluate the concurrent validity at each time. A comparison of the average scores between PS will be performed using the t-test. Citation Format: Yoko Suzuki, Naruto Taira, Yukiko Kajiwara, Mariko Kochi, Takayuki Iwamoto, Hirokuni Ikeda, Tadahiko Shien, Hiroyoshi Doihara, Yuichiro Kikawa, Yukari Uemura. Validation study of the Emoji scale in evaluating patient reported outcomes for breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr OT3-19-01.

Systemic therapies for operable breast cancer patients have improved outcomes and have thus become standard treatments. Recently, new molecular target drugs and regimens are being developed based on the predicted sensitivity for specific breast cancer histological types. Systemic therapy is selected according to recurrence risk, with the treatment for low-risk patients being de-escalated, while high-risk patients receive aggressive systemic treatment with an adequate dose and duration. Neoadjuvant systemic therapy has a different aim. The efficacy of systemic therapies, based on the sensitivities to drugs, is supported by improvements in the rate of breast-conserving therapy. The response to neoadjuvant systemic therapy is the most important factor for predicting outcomes and selecting the optimal adjuvant therapy. Novel biological markers unique to individual patients allow appropriate targeted therapy, which can achieve optimal efficacy.

Metastatic breast cancer (MBC), including de novo stage IV, is regarded as being incurable and the mainstay of clinical management is systemic therapy. Traditionally, locoregional surgery is performed only for local control, such as to prevent ulceration and bleeding. In recent years, however, both retrospective and prospective studies have demonstrated the prognostic efficacy of primary surgery for de novo stage IV patients. Therefore, we conducted a meta-analysis to evaluate whether surgical therapy contributes to overall survival (OS) extension. We searched for clinical trials published in electronic databases (PubMed, Embase, and the Cochrane databases) and performed a meta-analysis of the data collected. There were five prospective randomized controlled phase III trials (RCTs). The results of three have been reported. According to our meta-analysis of these RCTs, primary surgery for de novo stage IV breast cancer patients significantly improves OS. However, the Tata trial showed that systemic therapy does not achieve a sufficient effect. Another trial, conducted in Turkey, had statistical shortcomings and patient randomization was not adequately performed The ABCSG (Austrian Breast and Colorectal Cancer Study Group) trial had too few subjects. Meta-analysis of 12 retrospective studies showed that patients with stage IV breast cancer receiving surgery as the initial treatment experienced longer OS (HR: 0.65, P

Molecular‐targeted therapies directed against human epidermal growth factor receptor 2 (HER2) are evolving for various cancers. Neratinib is an irreversible pan‐HER tyrosine kinase inhibitor and has been approved by the FDA as an effective drug for HER2‐positive breast cancer. However, acquired resistance of various cancers to molecular‐targeted drugs is an issue of clinical concern, and emergence of resistance to neratinib is also considered inevitable. In this study, we established various types of neratinib‐resistant cell lines from HER2‐amplified breast and lung cancer cell lines using several drug exposure conditions. We analyzed the mechanisms of emergence of the resistance in these cell lines and explored effective strategies to overcome the resistance. Our results revealed that amplification of YES1, which is a member of the SRC family, was amplified in two neratinib‐resistant breast cancer cell lines and one lung cancer cell line. Knockdown of YES1 by siRNA and pharmacological inhibition of YES1 by dasatinib restored the sensitivity of the YES1‐amplified cell lines to neratinib in vitro. Combined treatment with dasatinib and neratinib inhibited tumor growth in vivo. This combination also induced downregulation of signaling molecules such as HER2, AKT and MAPK. Our current results indicate that YES1 plays an important role in the emergence of resistance to HER2‐targeted drugs, and that dasatinib enables such acquired resistance to neratinib to be overcome., We found that YES1 played an important role in the emergence of resistance to neratinib. The combination therapy of dasatinib, which is a YES1 inhibitor, plus neratinib enabled the resistance to neratinib to be overcome.

Background The HORSE-BC study previously demonstrated that second-line endocrine therapy (ET) for patients with acquired endocrine-resistant metastatic breast cancer (MBC) still provided a clinically meaningful benefit. Herein, we investigated the health-related quality of life (HR-QOL) in the HORSE-BC study. Methods Patients with acquired endocrine-resistant MBC who were scheduled for second-line ET were recruited. The HR-QOL was assessed at baseline, and 1 and 3 months after second-line ET initiation. To investigate the minimally important difference (MID) in the Functional Assessment of Cancer Therapy-Endocrine Symptoms (FACT-ES), we evaluated the means and standard deviations for the distribution-based method, and differences in the change in HR-QOL for the anchor-based method. We also investigated the association between FACT-ES total scores and clinical benefit. Results Overall, 56 patients were enrolled. Of these, 47 were analyzed. When defined as 1/3 standard deviation estimates based on the distribution method, the calculated MID was 5.9. The MIDs of the FACT-ES total scores based on the anchor method were 7.7 for decline and 4.1 for improvement. The MID decline proportions were 6.1% and 14.7% lower in patients who experienced clinical benefits than in those who did not at 1 and 3 months, respectively. The ratios of MID improvement in patients who experienced clinical benefits were 18.3% and 3.2% higher, respectively; the mean change in the FACT-ES total score from baseline improved in patients who experienced clinical benefits. Conclusions Maintaining the HR-QOL as determined by FACT-ES may be associated with clinical benefits in patients with acquired endocrine-resistant MBC treated with ET.

Our objectives were to determine whether clinic-pathological markers and immune-related gene signatures in breast cancer exhibit any change upon brain metastasis and whether previously reported genes significantly associated with brain metastases and the epithelial-mesenchymal transition (EMT) were reproducible and consistent in our dataset. Sixteen pair-matched samples from primary breast cancers and brain metastases diagnosed were collected from the Japan Clinical Oncology Group Breast Cancer Study Group. Gene expression profiles for immune-, brain metastases-, and EMT-related genes were compared between primary breast cancers and brain metastases. Potential therapeutic target genes of 41 FDA-approved or under-investigation agents for brain metastases were explored. Immune-related signatures exhibited significantly lower gene expression in brain metastases than in primary breast cancers. No significant differences were detected for the majority of genes associated with brain metastases and EMT in the two groups. Among 41 therapeutic target candidates, VEGFA and DNMT3A demonstrated significantly higher gene expression in brain metastases. We found that distinct patterns of gene expression exist between primary breast cancers and brain metastases. Further studies are needed to explore whether these distinct expression profiles derive from or underlie disease status and compare these features between metastases to the brain and other sites.

Background The 90-kDa heat-shock protein (HSP90) is a chaperone protein expressed at high levels in cancer cells and is involved in the folding or stabilization of several client proteins, including epidermal growth factor receptor (EGFR). Ganetespib is a second-generation HSP90 inhibitor with a potent antitumor effect against various cancer types. Materials and methods This study examined the antitumor effect of ganetespib in EGFR-mutant non-small cell lung cancer (NSCLC) cells and experimentally established EGFR-tyrosine kinase inhibitor (TKI)-resistant cells harboring various resistance mechanisms, including EGFR T790M mutation, met proto-oncogene amplification, and epithelial-mesenchymal transition. Results Ganetespib showed a potent antitumor effect at low concentrations, suppressing EGFR-related downstream pathway molecules and inducing cleavage of poly ADP-ribose polymerase in all examined EGFR-TKI-resistant cell lines in vitro. Ganetespib also inhibited in vivo tumor growth in resistant cells harboring EGFR T790M. Conclusion Ganetespib might be a promising therapeutic option for the treatment of patients with EGFR-TKI-resistant NSCLC.

Background: Overall survival (OS) is the established endpoint to evaluate the effects of drug treatment in comparative clinical trials of metastatic breast cancer. But assessing OS requires long follow-up periods and large sample size, which raise costs and create long delays in the drug approval process. Progression-free survival (PFS) or time to progression (TTP) is considered as a surrogate for OS and is often used as an alternative to OS. In some cancers the two endpoints are highly correlated, but in others they are not. Furthermore, the effect of breast cancer (BC) subtypes on the surrogacy of PFS/TTP for OS has not been completely defined. Method: A systematic literature review of randomized control trials was conducted to identify studies that reported both the hazard ratio (HR) of PFS/TTP and OS for BC subtypes {i.e. estrogen receptor (ER) positive, HER2 positive, and triple negative (TN)}. The correlation between the HR of PFS/TTP and OS was evaluated using weighted Spearman's rank correlation. Results: A total of 49 trials (34 phase III trials and 15 phase II trials) were selected for analysis. Among these trials, there were 8 comparison trials between one chemotherapy and another chemotherapy regimen, 18 comparison trials between chemotherapy and chemotherapy plus molecularly-targeted therapy, 9 comparison trials between one endocrine therapy and another endocrine therapy, and 5 comparison trials between endocrine therapy and endocrine therapy plus molecularly-targeted therapy. There were 17 trials reporting the HR of PFS/TTP and OS for ER positive, 16 trials for HER2 positive, and 9 trials for TN BC. Weighted Spearman's rank correlation revealed that coefficient between the HR of PFS/TTP and OS was 0.721(p Conclusion: There was a strong correlation between the HR of PFS/TTP and OS for ER positive BC, and a weak correlation between the HR of PFS/TTP and OS for HER2 positive and TN BC. The validity of using PFS/TTP as an OS surrogate marker was shown for metastatic BC, especially for ER positive BC. Citation Format: Tsukioki T, Taira N, Sakamaki K, Suzuki Y, Kajiwara Y, Hatono M, Takahashi Y, Kawata K, Kochi M, Iwamoto T, Ikeda H, Shien T, Doihara H. Progression-free survival or time to progression in comparative clinical trials of metastatic breast cancer as a potential surrogate for overall survival: A systematic review of 49 trials focusing on breast cancer subtype [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-19.

Background : Isoflavones are phytoestrogens that may be effective in preventing osteoporosis, reducing cardiovascular events, and improving menopausal symptoms such as hot flash due to their estrogen-like actions. Isoflavones are currently used as a supplement for improving symptoms of menopause. Epidemiological studies have shown that ingestion of soy products may also reduce the risk of breast cancer, and antitumor effects on hormone receptor (HR)-positive breast cancer cells have been shown in vitro for equol, an isoflavone metabolite. Equol binds to estrogen receptors (ERα, β) and is thought to antagonize ERα-estradiol binding in the presence of estradiol. Since equol shows an antiestrogenic effect, similar to that of the hormonal agent tamoxifen, it is thought that equol acts as a selective estrogen receptor modulator (SERM), but the mechanism is still unclear. In this study, we evaluated the antitumor effects of equol alone and in combination with existing therapeutic agents in HR-positive breast cancer cells, and examined the mechanism of these effects. Methods : The antitumor effects of equol alone and in combination with hormone drugs (4-hydroxytamoxifen (Tam), fulvestrant (Ful)) and chemotherapeutic agents (paclitaxel (Ptx), doxorubicin (Dox)) were examined using a MTS assay. Combination indexes (CIs) were determined in HR-positive MCF-7, T-47D, and ZR-75-1 cell lines. The mechanisms of the drug effects were evaluated by Western blot for assessment of changes in chemoresistance factors at the protein level. Results : In MCF-7, T-47D and ZR-75-1 cells, there was a concentration-dependent antitumor effect of equol and of the other hormonal agents. CIs showed an antagonistic effect of equol with Tam and a synergistic effect with Ful in all cell lines. Equol also had an antagonistic effect with the two chemotherapeutic agents, with the strongest antagonism occurring at a low dose of equol. Western blot showed that ER, PgR, Cyclin D1 and Bcl-2 were upregulated via ER at a low concentration of equol, similarly to the effect of 17-β-estradiol (E2), and ER, PgR, Cyclin D1 and Bcl-2 were downregulated at a high concentration, similarly to the effect of Tam. In addition, ER, PgR and cyclin D1 were downregulated with the combination of equol and Tam, while the expression of Bcl-2, a chemoresistance factor, increased. Conclusion : These results suggest that equol has a concentration-dependent antitumor effect in HR-positive breast cancer cell lines and may antagonize the effect of existing therapeutic agents (hormone drugs and chemotherapeutic agents). In particular, it was considered that in combination of equol and Tam, the apoptosis inducing action of each drug was attenuated and antagonistic effect was shown. Citation Format: Hatono M, Ikeda H, Taira N, Suzuki Y, Kajiwara Y, Kawata K, Takahashi Y, Tsukioki T, Kochi M, Iwamoto T, Shien T, Doihara H. Effects of a soy isoflavone in breast cancer treatment [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-05-06.

Background:It is unclear how to define responsiveness to endocrine therapy (ET) during the clinical course of advanced breast cancer (ABC), especially in evaluation of the effect of sequential ET. Objective:The goal of the study was to evaluate the efficacy of second line treatment of physician's choice (2nd-line TPC) for estrogen receptor-positive (ER+) and HER2-negative postmenopausal ABC with very low or low sensitivity to initial ET. Methods:A multicenter prospective observational cohort study was performed for 2nd-line TPCs. ABC with low sensitivity to initial ET was defined as recurrence within 5 years (yrs) during adjuvant ET or progression within 9 months (mo.) of initial ET. Similarly, ABC with very low sensitivity to initial ET was defined as recurrence within 2 yrs during adjuvant ET or progression within 3 mo. of initial ET. The expected clinical benefit rate (CBR: defined as patients who achieved CR, PR or SD for 24 weeks) was 50%. The null hypothesis of a CBR of 30% was tested with a one-sided α of 5%. 90% confidence intervals (CIs) were calculated for hypothesis tests. Results: A total of 56 patients (pts) were enrolled, but 7 were ineligible and one discontinued before starting the protocol treatment. The median age was 66 yrs (range: 41-88) and the median BMI was 23.4 kg/m2 (16.4-31.9). All pts were ER+ and 80% were PgR+. Most of pts had a baseline PS of 0 or 1, 90% had invasive ductal carcinoma, and 10% had invasive lobular carcinoma. Postoperative recurrence was detected in 84% and these pts had a median duration of adjuvant ET of 30.5 mo. (5.3-58.9). De novo stage IV ABC was present in 16%, with a median duration of first-line ET of 5 mo. (2.3-10.8). Adjuvant chemotherapy including anthracycline- and/or a taxane-containing regimen was administered in 58% (29/49). As adjuvant ET before initial recurrence, 34 pts received non-steroidal aromatase inhibitors (AIs) (88.0%), 1 received a steroidal AI (2.3%), and 3 received a selective estrogen receptor modulator (SERM). As first line ET in de novo stage IV, 7 pts (14%) were treated with AIs or a SERM (1 case). 2nd-line TPCs were also used, with 40 pts receiving fulvestrant (82%), 5 receiving SERMs (10%), 3 receiving a mTOR inhibitor plus a steroidal AI (6%), and one patient receiving an AI alone. The overall CBR was 44.9% (90% CI: 34.6-57.6, p=0.009), and CBR was similar across following subgroups (PgR+: n=39, 51.3%, 90% CI: 39.6-65.2, p=0.0016; very low sensitivity group: n=17, 58.8%, 90% CI: 42.0-78.8, p=0.003; non-visceral metastases: n=25, 40%, 90% CI; 34.1-65.9, p=0.0175). However, there were not statistically significant CBR in PgR- (n=10, 20.0%, 90% CI; 8.73-50.7, p=0.617), fulvestrant subgroup (n=40, 40.0 %, 90% CI; 29.2-54.2, p=0.063), low sensitive group (n=32, 37.5%, 90% CI; 26.0-53.6, p=0.1326), and visceral metastases (n=24, 48%, 90%CI; 28.2-60.3 p=0.072). The median PFS was 7.1 mo. (95% CI: 5.6-10.6). Conclusion:This study shows that 2nd line ETs was effective and might be a valid option in the sequence of treatments for postmenopausal women with ABC with low sensitivity to initial ET. It was suggested that PgR and visceral metastasis were significant predictive factors for CBR. Citation Format: Araki K, Fujisawa T, Sakamaki K, Kikawa Y, Iwamoto T, Sangai T, Shien T, Takao S, Nishimura R, Takahashi M, Aihara T, Mukai H, Taira N. Sequential second line endocrine therapy is still an effective strategy for postmenopausal ER+ and HER2- advanced breast cancer with low sensitivity to initial endocrine therapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-13-09.

The eighth editions of the primary tumor, lymph node and metastasis classifications for breast cancer issued by the American Joint Commission of Cancer and the Union for International Cancer Control were revised in 2017. The major change made by the American Joint Commission of Cancer is to incorporate biological factors such as estrogen and progesterone receptor, human epidermal growth factor receptor 2, histological grade and multigene prognostic assays, into the staging system. Tumor biomarkers and low recurrence scores confirmed by multigene prognostic assays change the staging. Minor changes are to add the post-neoadjuvant therapy clinical and pathological classification and to define the size of tumor, lymph node and metastasis components more precisely. Little has changed in the Union for International Cancer Control. We have identified key points of change in both eighth editions of the tumor, lymph node and metastasis classifications and we discuss possible problems which may arise when they are adopted in Japanese practice, as well as future directions.