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Background: High-risk lesions (HRL) of the breast are risk factors for future breast cancer development and may be associated with a concurrent underlying malignancy when identified on needle biopsy; however, there are few data evaluating HRLs in carriers of germline pathogenic variants (PVs) in breast cancer predisposition genes., Methods: We identified patients from two institutions with germline PVs in high- and moderate-penetrance breast cancer predisposition genes and an HRL in an intact breast, including atypical ductal hyperplasia (ADH), flat epithelial atypia (FEA), and lobular neoplasia (LN). We calculated upgrade rates at surgical excision and used Kaplan-Meier methods to characterize 3-year breast cancer risk in patients without upgrade., Results: Of 117 lesions in 105 patients, 65 (55.6%) were ADH, 48 (41.0%) were LN, and 4 (3.4%) were FEA. Most PVs (83.8%) were in the BRCA1/2, CHEK2 and ATM genes. ADH and FEA were excised in most cases (87.1%), with upgrade rates of 11.8% (95% confidence interval [CI] 5.5-23.4%) and 0%, respectively. LN was selectively excised (53.8%); upgrade rate in the excision group was 4.8% (95% CI 0.8-22.7%), and with 20 months of median follow-up, no same-site cancers developed in the observation group. Among those not upgraded, the 3-year risk of breast cancer development was 13.1% (95% CI 6.3-26.3%), mostly estrogen receptor-positive (ER +) disease (89.5%)., Conclusions: Upgrade rates for HRLs in patients with PVs in breast cancer predisposition genes appear similar to non-carriers. HRLs may be associated with increased short-term ER+ breast cancer risk in PV carriers, warranting strong consideration of surgical or chemoprevention therapies in this population., (© 2024. Society of Surgical Oncology.)

Background: The impact of ATM, CHEK2, and PALB2, the three most prevalent moderate-risk breast cancer genes, on surgical decision making is not well known., Methods: Our retrospective study included patients with resectable non-metastatic breast cancer who underwent multigene panel testing between July 2014 and January 2020 with at least one genetic alteration (pathogenic or variant of uncertain significance [VUS] in ATM [n = 49], CHEK [n = 57], or PALB2 [n = 27]). Our objectives were to determine the rate of contralateral prophylactic mastectomy (CPM) and the rate of bilateral breast cancer. Univariable analyses (UVA) and multivariable analyses (MVA) were performed to identify factors associated with CPM and bilateral breast cancer., Results: The rate of CPM was 39% (n = 49/127), with 54% (n = 25/46) of patients with a pathogenic mutation and 30% (n = 24/81) of patients with a VUS choosing CPM. On MVA, premenopausal status (odds ratio [OR] 3.46) and a pathogenic alteration (OR 3.01) were associated with increased use of CPM. Bilateral disease was noted in 16% (n = 22/138). Patients with pathogenic mutations had a 22% (n = 11/51) incidence of bilateral breast cancer, while patients with VUS had a 13% (n = 11/87) incidence, although this was not statistically significant on UVA or MVA. On MVA, premenopausal status was associated with a decreased risk of bilateral disease (OR 0.33, p = 0.022). During follow-up, a breast cancer event occurred in 16% (n = 22/138)., Conclusions: Our study identified a high rate of CPM among those with ATM, CHEK2, and PALB2 alterations, including VUS. Further studies are needed to clarify reasons for CPM among patients with moderate-risk alterations., (© 2023. Society of Surgical Oncology.)

Background: RxPONDER showed no benefit of adjuvant chemotherapy in postmenopausal women with estrogen receptor (ER) positive/human epidermal growth factor receptor 2 (HER2) negative breast cancer and limited nodal burden (pN1) with a recurrence score ≤ 25, suggesting that axillary staging could be omitted in cN0 patients if significant numbers of such women do not have pN2-3 disease. Here we evaluate the pN2-3 disease rate in a large cohort of postmenopausal women presenting with cN0 breast cancer., Patients and Methods: Consecutive postmenopausal patients presenting with T1-2N0 breast cancer who underwent axillary surgery from February 2006 to December 2011 were identified. Clinicopathologic characteristics associated with pN2-3 disease were examined using chi-square or Fisher's exact tests., Results: Of 3363 postmenopausal women with cT1-2N0 breast cancer (median age 58 years, IQR 48-67 years), median tumor size was 1.3 cm (IQR 0.90-1.90cm). Post-axillary staging, 2600 (77.3%) were pN0, 643 (19.1%) were pN1, and 120 (3.6%) were pN2-3. The pN2-3 disease rate did not differ across subtypes (4.4% HER2 + , 3.5% HR - /HER2 - , 3.5% HR + /HER2 - , p = 0.70). In the subset with HR + /HER2 - tumors, on multivariable analysis, age < 65 years (odds ratio [OR] 2.38, 95% confidence interval [CI] 1.32-4.49), lymphovascular invasion (OR 5.29, 95% CI 2.72-11.2), multifocal/centric tumors (OR 3.08, 95% CI 1.79-5.32), and tumor size > 2 cm (OR 5.51, 95% CI 3.05-10.4) were significantly associated with pN2-3 nodal burden. Of 506 patients with tumors > 2 cm, 49 (9.7%) had pN2-3 disease; in the subset of 90 patients age < 65 years who had multifocal/centric tumors > 2 cm, 23 (25.6%) had pN2-3 disease., Conclusions: In postmenopausal women with cN0 disease, pN2-3 nodal burden is uncommon; omitting axillary staging would not miss a significant number of patients who might benefit from adjuvant chemotherapy. Information available preoperatively indicating a higher risk of nodal disease such as younger age and large, multifocal tumors should be considered in the multidisciplinary management of the axilla., (© 2022. Society of Surgical Oncology.)

Introduction: Although outcomes are similar following breast-conserving surgery (BCS) or mastectomy among sporadic breast cancer patients, data are mixed for women with a germline BRCA mutation. We sought to compare outcomes among a modern cohort of BRCA mutation carriers undergoing BCS versus mastectomy., Methods: Women with a BRCA mutation and an index breast cancer from 2006-2015 were retrospectively identified from institutional databases. Factors, including date of genetic testing, clinicopathologic details, and treatment characteristics, were identified. Subsequent locoregional recurrence (LRR), distant recurrence, contralateral breast cancer (CBC), breast cancer-specific survival (BCSS), and overall survival (OS) events were compared between groups., Results: A total of 395 BRCA mutation carriers with 424 cancers were identified. Surgical treatment included BCS for 99 cancers and mastectomy for 325 cancers. Patients choosing mastectomy were more likely to have bilateral breast cancer, be younger/premenopausal, and be aware of their genetic status before surgery, and were less likely to receive radiation therapy (p < 0.001). At 7.9 years median follow-up, LRR, distant recurrence, BCSS, and OS rates did not differ between groups. CBC occurred in 5 versus 0 women treated with unilateral versus bilateral surgery, respectively, resulting is a 10-year estimated CBC risk of 14% among unilateral breast surgery patients (p < 0.001)., Conclusions: With nearly 8 years follow-up, we report no difference in LRR, BCSS, and OS among BRCA mutation carriers who underwent BCS or mastectomy; however, we report a higher incidence of CBC among those undergoing unilateral breast surgery. These data support BCS as an option for BRCA mutation carriers willing to continue high-risk screening., (© 2022. Society of Surgical Oncology.)

Purpose: Lobular carcinoma in situ (LCIS) confers increased cancer risk in either breast, but it remains unclear if this population is at increased risk for bilateral breast cancer (BC) development. Here we report bilateral BC incidence among women with a history of LCIS., Methods: Women with classic-type LCIS diagnosed from 1980 to 2017 who developed unilateral BC (UBC) or bilateral BC were identified. Bilateral BC was categorized as synchronous (bilateral BC diagnosed < 6 months apart; SBBC) or metachronous (bilateral BC diagnosed ≥ 6 months apart; MBBC). Five-year incidence rates of bilateral BC among this population were evaluated. Comparisons were made to identify factors associated with bilateral BC., Results: At 7 years' median follow-up, 249/1651 (15%) women with LCIS developed BC; 34 with bilateral BC (2%). There were no clinicopathologic feature differences between those with UBC and bilateral BC. SBBC occurred in 18 without significant differences versus UBC. Among 211 with UBC and a contralateral breast at risk, 16 developed MBBC at a median follow-up of 3 years. MBBC patients were less likely to receive endocrine therapy and more likely to receive chemotherapy versus UBC. Tumor histology was not associated with MBBC. Estimated 5-year MBBC risk was 6.4%. Index estrogen/progesterone receptor positivity and endocrine therapy were the only factors associated with MBBC risk., Conclusion: Bilateral BC occurred in 2% of women with LCIS history at median follow-up of 7 years. Similar to the general BC population, a decrease in MBBC is seen among women with a history of LCIS who develop hormone receptor-positive disease and those who receive endocrine therapy, highlighting the protective effects of this treatment., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: The Breast Cancer Surveillance Consortium (BCSC) model predicts risk of invasive breast cancer risk based on age, race, family history, breast density, and history of benign breast disease, including lobular carcinoma in situ (LCIS). However, validation studies for this model included few women with LCIS. We sought to evaluate the accuracy of the BCSC model among this cohort., Methods: Women with LCIS diagnosed between 1983 and 2017 were identified from a prospectively maintained database. The BCSC score was calculated; those with prior breast cancer, unknown breast density, age < 35 years or > 74 years, or with history of chemoprevention use were excluded. The Kaplan-Meier method was used to estimate incidence rates. Time-dependent receiver operating characteristic (ROC) analysis was used to analyze the discriminative capacity of the model., Results: 1302 women with LCIS were included. At a median follow-up of 7 years, 152 women (12%) developed invasive cancer (6 with bilateral disease). Cumulative incidences of invasive breast cancer were 7.1% (95% CI 5.6-8.7) and 13.3% (95% CI 10.9-15.6), respectively, and the median BCSC risk scores were 4.9 and 10.4, respectively, at 5 and 10 years. The median 10-year BCSC score was significantly lower than the 10-year Tyrer-Cuzick score (10.4 vs 20.8, p < 0.001). The ROC curve scores (AUC) for BCSC at 5 and 10 years were 0.59 (95% CI 0.52-0.66) and 0.58 (95% CI 0.52-0.64), respectively., Conclusion: The BCSC model has moderate accuracy in predicting invasive breast cancer risk among women with LCIS with fair discrimination for risk prediction between individuals., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Neoadjuvant chemotherapy (NAC) is increasingly used for clinically node-positive (cN+) tumors with intact primary breast cancer (IPBC) to downstage the axilla, and those who convert to cN0 may be eligible for sentinel lymph node biopsy (SLNB). Rates of axillary downstaging in occult primary breast cancer (OPBC) are unknown., Objective: The aim of this study was to determine the frequency of nodal pathologic complete response (pCR) following NAC in a cohort of patients with OPBC., Methods: Twenty-eight patients with stage II/III OPBC treated between January 2008 and December 2019 were identified. Twenty patients had cN1-3 OPBC, pretreatment lymph node needle biopsy, and received NAC; these constituted the study population. Treatment factors and nodal pCR rates were summarized by tumor subtype., Results: Median age at diagnosis was 54 years. Most patients presented with cN1 disease (75%) and ductal histology (80%). Nodal pCR was seen in 16/20 (80%) patients. Eight (40%) patients were triple negative, 6 (30%) were estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER +/HER2 -), and 6 (30%) were HER2 positive, with pCR rates of 88%, 50%, and 100%, respectively. Among the 15 patients who presented as cN1, 14 (93%) converted to cN0 following NAC. Of these, nine underwent SLNB and all achieved nodal pCR (100%)., Conclusion: In this small series, 80% of OPBC patients achieved nodal pCR following NAC. pCR rates varied by receptor profile, being lowest in the ER positive/HER2 negative group and highest in the HER2 positive group (50-100%); however, these rates are excellent and numerically exceed those in the literature for IPBC. Given the pCR rate, SLNB may be an option in select OPBC patients who downstage following NAC.

Background: Neoadjuvant endocrine therapy (NET) is effective in downstaging large hormone receptor-positive (HR+) breast cancers and increasing rates of breast-conserving surgery (BCS), but data regarding nodal pathologic complete response (pCR) are sparse. We reported nodal and breast downstaging rates with NET, and compared axillary response rates following NET and neoadjuvant chemotherapy (NAC)., Methods: Consecutive stage I-III breast cancer patients treated with NET and surgery from January 2009 to December 2019 were identified from a prospectively maintained database. Nodal pCR rates were compared between biopsy-proven node-positive patients treated with NET, and HR+/HER2- patients treated with NAC from November 2013 to July 2019., Results: 127 cancers treated with NET and 338 with NAC were included. NET recipients were older, more likely to have lobular and lower-grade tumors, and higher HR expression. With NET, the nodal pCR rate was 11% (4/38) of biopsy-proven cases, and the breast pCR rate was 1.6% (2/126). Nodal-dowstaging rates with NET and NAC were not significantly different (11% vs 18%; P = 0.37). Patients achieving nodal pCR with NET versus NAC were older (median age 70 vs 50, P = 0.004) and had greater progesterone receptor (PR) expression (85% vs 13%, P = 0.031), respectively. Of patients not candidates for BCS due to a large tumor relative to breast size, 36/47 (77%) became BCS-eligible with NET (median PR expression 55% vs 5% in those remaining ineligible, P < 0.05)., Conclusion: Although nodal pCR is more frequent than breast pCR, NET is more likely to de-escalate breast surgery than axillary surgery. However, with a nodal pCR rate of 11%, NET remains an option for downstaging node-positive patients without clear indications for NAC.

Purpose: Both body mass index (BMI) and breast density impact breast cancer risk in the general population. Whether obesity and density represent additive risk factors in women with lobular carcinoma in situ (LCIS) is unknown., Methods: Patients diagnosed with LCIS from 1988 to 2017 were identified from a prospectively maintained database. BMI was categorized by World Health Organization classification. Density was captured as the mammographic Breast Imaging Reporting and Data System (BIRADS) value. Other covariates included age at LCIS diagnosis, menopausal status, family history, chemoprevention, and prophylactic mastectomy. Cancer-free probability was estimated using the Kaplan-Meier method, and Cox regression models were used for univariable and multivariable analyses., Results: A total of 1222 women with LCIS were identified. At a median follow-up of 7 years, 179 women developed breast cancer (121 invasive, 58 ductal carcinoma in situ); 5- and 10-year cumulative incidences of breast cancer were 10% and 17%, respectively. In multivariable analysis, increased breast density (BIRADS C/D vs. A/B) was significantly associated with increased hazard of breast cancer (hazard ratio [HR] 2.42, 95% confidence interval [CI] 1.52-3.88), whereas BMI was not. On multivariable analysis, chemoprevention use was associated with a significantly decreased hazard of breast cancer (HR 0.49, 95% CI 0.29-0.84). Exploratory analyses did not demonstrate significant interaction between BMI and menopausal status, BMI and breast density, BMI and chemoprevention use, or breast density and chemoprevention., Conclusions: Breast cancer risk among women with LCIS is impacted by breast density. These results aid in personalizing risk assessment among women with LCIS and highlight the importance of chemoprevention counseling for risk reduction.

Background: In the ACOSOG (American College of Surgeons Oncology Group) Z0011 trial and the AMAROS (After Mapping of the Axilla: Radiotherapy or Surgery?) trial, matted nodes with gross extracapsular extension (ECE), a risk factor for locoregional recurrence, were an indication for axillary lymph node dissection (ALND), but the effect of microscopic ECE (mECE) in the sentinel lymph nodes (SLNs) on recurrence was not examined., Methods: Between 2010 and 2017, 811 patients with cT1-2N0 breast cancer and SLN metastasis were prospectively managed according to Z0011 criteria, with ALND for those with more than two positive SLNs or gross ECE. Management of mECE was not specified. In this study, we compare outcomes of patients with one to two positive SLNs with and without mECE, treated with SLN biopsy alone (n = 685)., Results: Median patient age was 58 years, and median tumor size was 1.7 cm. mECE was identified in 210 (31%) patients. Patients with mECE were older, had larger tumors, and were more likely to be hormone receptor positive and HER2 negative, have two positive SLNs, and receive nodal radiation. At a median follow-up of 41 months, no isolated axillary failures were observed. There were 11 nodal recurrences; two supraclavicular ± axillary, four synchronous with breast, and five with distant failure. The five-year rate of any nodal recurrence was 1.6% and did not differ by mECE (2.3% vs. 1.3%; p = 0.84). No differences were observed in local (p = 0.08) or distant (p = 0.31) recurrence rates by mECE status., Conclusions: In Z0011-eligible patients, nodal recurrence rates in patients with mECE are low after treatment with SLN biopsy alone, even in the absence of routine nodal radiation. The presence of mECE should not be considered a routine indication for ALND.

Background: The Tyrer-Cuzick model has been shown to overestimate risk in women with atypical hyperplasia, although its accuracy among women with lobular carcinoma in situ (LCIS) is unknown. We evaluated the accuracy of the Tyrer-Cuzick model for predicting invasive breast cancer (IBC) development among women with LCIS., Methods: Women with LCIS participating in surveillance from 1987 to 2017 were identified from a prospectively maintained database. Tyrer-Cuzick score (version 7) was calculated near the time of LCIS diagnosis. Patients with prior or concurrent breast cancer, a BRCA mutation, receiving chemoprevention, or with pleomorphic LCIS were excluded. Invasive cancer-free probability was estimated using the Kaplan-Meier method., Results: A total of 1192 women with a median follow-up of 6 years (interquartile range [IQR] 2.5-9.9) were included. Median age at LCIS diagnosis was 49 years (IQR 45-55), 88% were white; 37% were postmenopausal, 28% had ≥ 1 first-degree family member with breast cancer, and 13% had ≥ 2 second-degree family members with breast cancer. In total, 128 patients developed an IBC; median age at diagnosis was 54 years (IQR 49-61). Five- and 10-year cumulative incidences of invasive cancer were 8% (95% confidence interval [CI] 6-9%) and 14% (95% CI 12-17%), respectively. The median Tyrer-Cuzick 10-year risk score was 20.1 (IQR 17.4-24.3). Discrimination measured by the C-index was 0.493, confirming that the Tyrer-Cuzick model is not well calibrated in this patient population., Conclusions: The Tyrer-Cuzick model is not accurate and may overpredict IBC risk for women with LCIS, and therefore should not be used for breast cancer risk assessment in this high-risk population.

Background/objective: The efficacy of chemoprevention for breast cancer risk reduction has been demonstrated in randomized controlled trials; however, use remains low. We sought to determine whether uptake differed by risk factors, and to identify reasons for refusal and termination., Methods: Women seen in a high-risk clinic from October 2014 to June 2017 considered eligible for chemoprevention (history of lobular carcinoma in situ, atypia, family history of breast/ovarian cancer, genetic mutation, or history of chest wall radiation) were retrospectively identified. Breast cancer risk factors were compared among those with and without chemoprevention use, and compliance was noted., Results: Overall, 1506 women were identified, 24% with prior/current chemoprevention use. Women ≥ 50 years of age were more likely to use chemoprevention than women < 50 years of age (28% vs. 11%, p < 0.001). Chemoprevention use by risk factor ranged from 7 to 40%. Having multiple risk factors did not increase use. Significant variation by risk factor was present among women ≥ 50 years of age (p < 0.001), but not among women < 50 years of age (p = 0.1). Among women with a documented discussion regarding chemoprevention (575/1141), fear of adverse effects was the most common refusal reason (57/156; 36%). The majority of women (61%) who initiated chemoprevention completed 5 years., Conclusion: Chemoprevention use among women at increased risk for breast cancer remains low, with more frequent use among women ≥ 50 years of age. These data highlight the need for ongoing educational efforts and counseling, as the majority who begin therapy complete 5 years of use. Given the fear of adverse effects as well as low uptake, particularly among women < 50 years of age, alternative risk-reducing strategies are needed.

Background and Objectives: Women with unilateral early-stage breast cancer are increasingly choosing contralateral prophylactic mastectomy (CPM) despite the absence of survival benefits and increased risk of surgical complications. Data are lacking on whether this trend extends to women with clinically locally advanced nonmetastatic (cT4M0) cancer. This study aims to estimate national CPM trends in women with unilateral cT4M0 breast cancer., Methods: Women aged ≥ 18 years, who underwent mastectomy during 2004 to 2014 for unilateral cT4M0 breast cancer were identified using the National Cancer Database and grouped as all locally advanced (T4), chest wall invasion, skin nodule/ulceration, or both (T4abc), and inflammatory (T4d) cancer. Poisson regression for trends and logistic modeling for predictors of CPM were performed., Results: Of 23 943 women, 41% had T4abc disease and 35% T4d. Cumulative CPM rates were 15%, 23%, and 18%, for the T4abc, T4d, and all T4 groups, respectively. Trend analysis revealed a significant upsurge in CPM demonstrating 12% annual growth for T4abc tumors, 8% for T4d and 9% for all T4 (all P < 0.001)., Conclusions: Increasing numbers of women with unilateral cT4M0 breast cancer are undergoing CPM. This rising trend warrants further research to understand stakeholders' preferences in surgical decision-making for women with locally advanced breast cancer., (© 2018 Wiley Periodicals, Inc.)

Background: The current study was conducted to examine the association between ipsilateral breast tumor recurrence (IBTR) and the timing of radiotherapy (RT) in women with ductal carcinoma in situ (DCIS) undergoing breast-conserving surgery (BCS)., Methods: Women with DCIS who were treated with BCS and RT from 1980 through 2010 were identified from a prospectively maintained database. IBTR rates, measured from the time of RT completion, were compared between those who initiated RT ≤8 weeks, >8 to 12 weeks, and >12 weeks after the completion of surgery. The association between RT timing and IBTR was evaluated by Kaplan-Meier and log-rank analyses; Cox modeling was used for multivariable analysis., Results: A total of 1323 women met the inclusion criteria. The median follow-up was 6.6 years, with 311 patients followed for ≥10 years. A total of 126 IBTR events occurred. Patients were categorized by RT timing: 806 patients (61%) with timing of ≤8 weeks, 386 patients (29%) with timing of >8 to 12 weeks, and 131 patients (10%) with timing >12 weeks. The 5-year and 10-year IBTR rates were 5.8% and 13.0%, respectively, for RT starting ≤8 weeks after surgery; 3.8% and 7.6%, respectively, for RT starting >8 to 12 weeks after surgery; and 8.8% and 23.0%, respectively, for an RT delay >12 weeks after surgery (P = .004). On multivariable analysis, menopause (hazard ratio [HR], 0.54; P = .0009) and endocrine therapy (HR, 0.45; P = .002) were found to be protective against IBTR, whereas a delay in RT >12 weeks compared with ≤8 weeks was associated with a higher risk of IBTR (HR, 1.92; P = .014). There was no difference in IBTR noted between RT initiation at ≤8 weeks and initiation at >8 to 12 weeks after BCS (P = .3)., Conclusions: A delay in RT >12 weeks is associated with a significantly higher risk of IBTR in women undergoing BCS for DCIS. Efforts should be made to avoid delays in starting RT to minimize the risk of disease recurrence. Cancer 2018;124:46-54. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Background: The phrase "high-risk for breast cancer" is used to identify various groups at elevated cancer risk, and the appropriate surveillance and risk-reducing strategies differ based on the etiology of risk. Here, we review the utility of patient-reported data to capture women with modifiable lifestyle risk factors and those suitable for genetic counseling referral., Methods: Patient-reported data from a web-based survey were used to capture personal history, multi-generational family history, and lifestyle factors (body mass index, alcohol consumption, physical activity). Responses were tabulated, and percentage of patients who met criteria for possible intervention calculated., Results: 1277 women completed the survey from October 2014 to December 2015. Women were considered high risk for a combination of the following: family history of breast and/or ovarian cancer (77%), history of atypical hyperplasia or lobular carcinoma in situ (35%), known breast cancer-related gene mutation (11%). Based on self-reported data, 65% qualified for genetic evaluation but 40% reporting no prior testing. Only half of the population met national physical activity recommendations, nearly 40% were overweight/obese, and 18% reported consuming ≥1 alcoholic beverage per day., Conclusions: Among women followed in a high-risk breast surveillance program, there is considerable opportunity for improved genetic referral and awareness of modifiable lifestyle factors based on self-reported data as 60% of respondents reported a possible area for intervention. While risk reduction associated with lifestyle changes is modest in comparison to chemoprevention or surgery, such changes are practically without risk, minimally expensive, and provide innumerable secondary health benefits.

Although substantial progress has been made in the screening and management of breast cancer, globally it remains the most common cause of cancer and cancer death in women. While breast cancer is potentially curable when detected at an early stage, it remains incurable in the metastatic setting. Thus, given its high prevalence, improved prevention and treatment of metastases remains a clinically meaningful unmet need. We review here the advances made in the last several years in the screening and treatment of breast cancer and explore how our increased insight into the underlying biology of breast cancer has influenced our efforts to individualize patient care.

Sentinel lymph node biopsy (SLNB) has revolutionized the surgical management of the axilla for patients with early breast cancer. SLNB initially became standard regional therapy for women who were both clinically and pathologically node-negative. Subsequently, SLNB has been established as appropriate management in patients with very low axillary tumor burden, defined as isolated tumor cells or micrometastatic disease (< 2 mm); it provides accurate staging information with no detriment to regional control. More recently, the treatment of the axilla has evolved for women with macrometastatic axillary disease. Three randomized controlled trials have compared different regional treatment strategies for patients with > 2 mm of axillary tumor burden. Here we review the evolution of SLNB for the management of clinically node-negative breast cancer, and we address the current controversies and management issues.