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Aim: Mammography is the mainstay of imaging surveillance after breast cancer (BC) treatment, but false negatives can occur. The objective of the study was to determine the factors that can predict poorer second breast cancer (SBC) mammogram detection of the ipsilateral and contralateral breast separately., Methods: A multicentre retrospective review was performed on female patients with a previous history of treated BC who developed a second breast cancer (SBC) in the ipsilateral (ISBC) or contralateral breast (CSBC) within 10 years from the first BC. SBC cases that occurred between January 2006 and October 2017 were included from the institutional database. The ISBC and CSBC mammogram-occult (MO) rates were correlated with mammographic breast density as well as various clinical, radiological and histological characteristics of the first BC., Results: 274 cases of SBC were evaluated. 39.4 % (108/274) of cases were ISBC and 60.6 % (166/274) were CSBC. 35 (32.4 %) of the ISBCs and 42 (25.3 %) of the CSBCs were MO (p = 0.218). On multivariate analysis, symptomatic first BC (p = 0.041), prevailing dense breast tissue at the time of SBC diagnosis (p = 0.003) and trabecular thickening on surveillance mammograms (p = 0.017) were associated with MO ISBC. MO first BC (p < 0.001) was the only factor found to correlate with MO CSBC., Conclusion: The study found various clinical, radiological and pathological factors associated with mammogram surveillance failure for the ipsilateral and contralateral breast. This information can provide additional guidance in the planning of a personalised surveillance program using adjunct imaging screening., Competing Interests: Declaration of competing interest We have no conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Neoadjuvant chemotherapy (NAC) is increasingly used in breast cancer. Predictive modeling is useful in predicting pathologic complete response (pCR) to NAC. We test machine learning (ML) models to predict pCR in breast cancer and explore methods of handling missing data., Methods: Four hundred and ninety-nine patients with breast cancer treated with NAC in two centers in Singapore (National Cancer Centre Singapore [NCCS] and KK Hospital) between January 2014 and December 2017 were included. Eleven clinical features were used to train five different ML models. Listwise deletion and imputation were evaluated on handling missing data. Model performance was evaluated by AUC and calibration (Brier score). Feature importance from the best performing model in the external testing data set was calculated using Shapley additive explanations., Results: Seventy-two (24.6%), 18 (24.7%), and 31 (24.8%) patients attained pCR in NCCS training, NCCS testing, and KK Women's and Children's Hospital (KKH) testing data sets, respectively. The random forest (RF) base and imputed models have the highest AUCs in the KKH cohort of 0.794 (95% CI, 0.709 to 0.873) and 0.795 (95% CI, 0.706 to 0.871), respectively, and were the best calibrated with the lowest Brier score. No statistically significant difference was noted between AUCs of the base and imputed models in all data sets. The imputed model had a larger positive predictive value (PPV; 98.2% v 95.1%) and negative predictive value (NPV; 96.7% v 90.0%) than the base model in the KKH data set. Estrogen receptor intensity, human epidermal growth factor 2 intensity, and age at diagnosis were the three most important predictors., Conclusion: ML, particularly RF, demonstrates reasonable accuracy in pCR prediction after NAC. Imputing missing fields in the data can improve the PPV and NPV of the pCR prediction model.

Background: Nodal involvement in ductal carcinoma in situ (DCIS) is rare. In patients with DCIS diagnosis prior to mastectomy, a sentinel lymph node biopsy (SLNB) is usually performed during mastectomy, to avoid the risk of reoperation and the non-identification of SLN subsequently, should there be an upgrade to invasive cancer. We aimed to study the feasibility of omitting SLNB in an under-screened cohort, with mostly symptomatic patients and DCIS diagnosis before mastectomy, by determining the upgrade rate to invasive cancer/ DCIS microinvasion (DCISM) and its associated risk factors., Methods: Patients with pure DCIS diagnosis premastectomy were reviewed retrospectively. Patients with known DCISM or invasive cancer before mastectomy and bilateral cancers were excluded. Patients' demographics, radiological and pathological data premastectomy were analyzed., Results: A total of 189 patients were included. The mean age was 53.8 (range: 29-85) years old. About 64.4% presented with symptoms. 36.0% and 15.3% upgraded to invasive cancer and DCISM on mastectomy respectively. Palpable tumor (P = .0036), large size on ultrasound (P = .0283), tumor seen on mammogram and ultrasound (P = .0082), ultrasound-guided biopsy (P < .0001), high-grade DCIS on biopsy (P = .0350) and no open biopsy/lumpectomy before mastectomy (P < .0001) were associated with the upgrade, with the latter factor remaining significant after multivariable analysis. Nodal involvement was 8.47% and was associated with invasive cancer (P < .0001)., Conclusion: In a cohort who had DCIS diagnosis before mastectomy and were mostly symptomatic, the upgrade rate was 51.3%. Despite the high upgrade rate, nodal involvement remained comparable. Risk factors could select patients for omission of upfront SLNB, with a delayed SLNB planned if needed., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Although considered a favorable subtype, pure mucinous breast cancer (PMBC) can recur, and evidence for adjuvant therapy is limited. We aimed to compare outcomes of nonmetastatic PMBC with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) to address these uncertainties., Methods: Individual patient-level data from 6 centers on stage I-III hormone receptor-positive and HER2-negative PMBC, IDC, and ILC were used to analyze recurrence-free interval (RFI), recurrence-free survival (RFS), and overall survival (OS), and to identify prognostic factors for PMBC., Results: Data from 20,684 IDC cases, 1,475 ILC cases, and 943 PMBC cases were used. Median follow-up was 6.6 years. Five-year RFI, RFS, and OS for PMBC were 96.1%, 94.9%, and 98.1%, respectively. On multivariable Cox regression, PMBC demonstrated superior RFI (hazard ratio [HR], 0.59; 95% CI, 0.43-0.80), RFS (HR, 0.70; 95% CI, 0.56-0.89), and OS (HR, 0.71; 95% CI, 0.53-0.96) compared with IDC. ILC showed comparable outcomes to IDC. Fewer than half (48.7%) of recurrences in PMBC were distant, which was a lower rate than for IDC (67.3%) and ILC (80.6%). In contrast to RFI, RFS events were driven more by non-breast cancer deaths in older patients. Significant prognostic factors for RFI among PMBC included positive lymph node(s) (HR, 2.42; 95% CI, 1.08-5.40), radiotherapy (HR, 0.44; 95% CI, 0.23-0.85), and endocrine therapy (HR, 0.25; 95% CI, 0.09-0.70). No differential chemotherapy associations with outcomes were detected across PMBC subgroups by nodal stage, tumor size, and age. A separate SEER database analysis also did not find any association of improved survival with adjuvant chemotherapy in these subgroups., Conclusions: Compared with IDC, PMBC demonstrated superior RFI, RFS, and OS. Lymph node negativity, adjuvant radiotherapy, and endocrine therapy were associated with superior RFI. Adjuvant chemotherapy was not associated with better outcomes.

Introduction: Bilateral breast cancers (BBC) diagnosed at an interval apart are uncommon. While metastatic staging guidelines are established in patients with unilateral breast cancer, its role in BBC diagnosed at an interval apart is unclear. We aim to identify the subgroup who would benefit from metastatic staging at contralateral cancer diagnosis. Methods: Eligible patients were divided into three categories: (A) ipsilateral invasive cancer and contralateral ductal carcinoma in situ (DCIS), (B) bilateral invasive cancers and (C) ipsilateral DCIS and contralateral invasive cancer and reviewed retrospectively. We excluded patients with bilateral DCIS, synchronous BBC diagnosed within 6 months from first cancer, patients who were stage IV at first cancer diagnosis and patients with recurrence prior to contralateral cancer. Results: Of 4516 newly diagnosed breast cancer patients, 79 patients were included. Systemic metastasis occurred in 15.6% of patients in Group B. Having nodal positivity of either cancer which were diagnosed ≤30 months apart and nodal positivity of only the contralateral cancer when diagnosed >30 months apart was significantly associated with systemic metastasis ( p = 0.0322). Conclusions: Both the nodal status and a 30 months cut-off time interval between the two cancers can be used to identify patients who will benefit from metastatic staging. This finding requires validation in larger studies.

Introduction: Chemotherapy is conventionally offered to non-stage IV breast cancer patients with metastatic nodes. However, the RxPONDER trial showed that chemotherapy can be omitted in selected patients with 1-3 metastatic nodes if the 21-gene assay recurrence score is ≤25. We aimed to investigate if axillary ultrasound can identify this group of patients with limited nodal burden so that they can undergo upfront surgery followed by gene assay testing, to potentially avoid chemotherapy., Methods: T1-3, node positive, hormone receptor-positive and HER2-negative breast cancer patients ≥50 years old with axillary lymph node dissection (ALND) were reviewed from 2 centres. Patients with neoadjuvant chemotherapy and bilateral cancers were excluded. Number of ultrasound-detected abnormal axillary nodes, demographic and histological parameters were correlated with the number of metastatic nodes found on ALND., Results: 138 patients were included, 59 (42.8%) and 79 (57.2%) patients had 1-3 and >3 metastatic nodes on ALND respectively. On logistic regression and ROC analysis, the number of ultrasound-detected abnormal nodes was significant (p < 0.001) for predicting limited nodal burden (ROC AUC = 0.7135). Probabilities of <4 metastatic nodes with ultrasound cut-offs of 5, 6 and 8 abnormal nodes were 0.057, 0.026 and 0.005 respectively, with 100% specificity., Conclusion: A cut-off of ≤5 ultrasound-detected abnormal nodes can distinguish between patients with limited versus high nodal burden, with high specificity. Hence, incorporating the number of abnormal ultrasound-detected nodes into clinical practice may prove useful in guiding between upfront surgery and gene assay testing or neoadjuvant chemotherapy in this group of patients.

Background: Exposure to cytotoxic chemotherapy treatment may alter DNA methylation (DNAm) in breast cancer patients., Methods: We performed DNAm analysis in 125 breast cancer patients with blood drawn before and after chemotherapy, using the Illumina MethylationEPIC array. DNAm changes of 588,798 individual CpGs (including 41,207 promoter regions) were evaluated using linear regression models adjusted for monocyte proportion. Gene set enrichment analyses (GSEA) were conducted to identify key Gene Ontology (GO) biological processes or Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with chemotherapy. Results were validated in a separate cohort of breast cancer patients who were treated (n = 1273) and not treated (n = 872) by chemotherapy (1808 blood, 337 saliva)., Results: A total of 141 differentially methylated CpGs and 11 promoters were significantly associated with chemotherapy after multiple testing corrections in both the paired sample and single time point analyses. GSEA of promoter regions (pre-ranked by test statistics) identified six suppressed biological processes (p < 4.67e-8) related to sensory perception and detection of chemical stimuli, including smell perception (GO:0007606, GO:0007608, GO:0009593, GO:0050906, GO:0050907, and GO:0050911). The same six biological processes were significantly suppressed in the validation dataset (p < 9.02e-14). The KEGG pathway olfactory transduction (hsa04740) was also found to be significantly suppressed (p paired-samples  = 1.72e-9, p single-timepoint-blood  = 2.03e-15 and p single-timepoint-saliva  = 7.52e-56)., Conclusion: The enrichment of imprinted genes within biological processes and pathways suggests a biological mechanism by which chemotherapy could affect the perception of smell., (© 2023. The Author(s).)

Introduction: In breast cancer patients undergoing mastectomy without reconstruction, an external breast prosthesis could aid patients' recovery, improve body image and confidence by helping to regain a symmetrical chest appearance when dressed. However, external breast prosthesis preferences among Asian breast cancer patients were not widely studied. We aimed to compare patients' experience with the conventional commercially manufactured standard-sized (small, medium, large, extra-large) bra and prosthesis versus customized hand-knitted external breast prosthesis with patient's bra after unilateral mastectomy at a tertiary hospital. This is the first such study in Asian women, to our knowledge., Methods: In this prospective study, participants used the conventional bra-prosthesis followed by the customized one consecutively, each for at least 3 months before they were administered an identical questionnaire at 3 and 6 months respectively. The questionnaire assessed the patients' experience with the prosthesis on the aspects of comfort, body image and satisfaction etc. Patients were also invited for in-depth interviews., Results: Of 155 eligible patients, 148 patients participated with a response rate of 95.5%. 99 (67%) participants preferred the customized prosthesis, while 38 (25.7%) did not. 11 (7.4%) participants were undecided. Seventeen participants underwent in-depth interviews until data saturation on major qualitative themes was achieved. More patients experienced excessive sweating (p < 0.0001), greater discomfort (p = 0.0195) and higher rates of prosthesis dislodgement (p = 0.0269) with the conventional bra-prosthesis., Conclusion: Customized external breast prostheses could be an alternative to the conventional ones for breast cancer patients with mastectomy, with additional benefits of less sweating, more comfort and less dislodgement perceived.

Introduction: Ductal carcinoma in situ (DCIS) in young women is rare and not well studied. Since they do not qualify for mammographic screening, they are more likely to present with symptoms. Young women have also been associated with poorer outcomes, but it is unknown whether presentation mode affects outcome. We aimed to compare characteristics of DCIS patients <40 years of age presenting with symptoms versus those without, and determine whether presentation mode affects recurrence., Methods: Pure DCIS patients aged <40 years were retrospectively analyzed. Clinical presentation, pathology and recurrence data were collected. Statistical analysis was performed to investigate the correlation of presentation mode with outcomes., Results: 40 patients with 41 cases were included. The mean age at diagnosis was 32.3 years (range 17-39). 73.2% and 26.8% presented with symptoms or abnormal imaging respectively. Of the cases who presented with symptoms, 86.7%, 10.0% and 3.3% had palpable lump, nipple discharge or breast pain, respectively. The average tumor size was 22.0 mm (range 2.0-86.9) and 12.2 mm (range 3-25) for patients who presented with symptoms and non-symptomatic group, respectively. Cases presenting with symptoms were statistically associated with higher grade (p = 0.0090). On median follow-up of 85 months, there were 3 (7.3%) recurrences, which were not statistically associated with presentation mode., Conclusion: Young women with DCIS tend to present with symptoms, with breast lump as the commonest symptom. Symptomatic patients tend to be associated with grade III tumours, compared to non-symptomatic patients. On long-term follow-up, mode of presentation was not statistically associated with recurrence.

Introduction: Little is known about second recurrences in breast cancer patients, especially in patients with mastectomy. We aimed to determine the risk factors, prevalence and patterns of second recurrence in mastectomy patients after first recurrence., Methods: Stage I-III breast cancer patients treated at a tertiary institution from 1st September 2005 to 31st October 2017 and developed first and second recurrences after mastectomy were retrospectively reviewed. We excluded patients with bilateral cancers and patients who were lost to follow-up. The demographics, pathological and recurrence data were collected from a prospectively maintained database and analysed., Results: Of the 1619 mastectomy patients, 214 (13.2%) patients developed recurrences at a mean 39.9 months from primary cancer diagnosis. 23, 8 and 183 had isolated chest wall recurrences (CWR), regional and systemic metastases, respectively. Excluding 2 CWR patients without surgery, second recurrences occurred in 3/21 (14.3%) and 3/8 (37.5%) in patients with CWR and regional metastasis at 27.7 months (range: 5-42) and 32 months (range: 18-40), respectively. In both groups, systemic metastasis as second recurrence occurred within 2 years after first recurrence, whilst locoregional second recurrences occurred later. No risk factors for second recurrence were identified., Conclusion: In patients with mastectomy, second recurrences occurred in 20.7% of patients with treated locoregional first recurrence, with no risk factors identified. Systemic metastases manifesting as second recurrence occurred in the first 2 years after first recurrence. Continued clinical surveillance and restaging patients in the first 2 years after first locoregional recurrence may enable early prognostication and treatment with the newer metastatic drugs., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Competing Interests: The author reports no conflicts of interest.

Background: Human leukocyte antigen (HLA) genes play critical roles in immune surveillance, an important defence against tumors. Imputing HLA genotypes from existing single-nucleotide polymorphism datasets is low-cost and efficient. We investigate the relevance of the major histocompatibility complex region in breast cancer susceptibility, using imputed class I and II HLA alleles, in 25,484 women of Asian ancestry., Methods: A total of 12,901 breast cancer cases and 12,583 controls from 12 case-control studies were included in our pooled analysis. HLA imputation was performed using SNP2HLA on 10,886 quality-controlled variants within the 15-55 Mb region on chromosome 6. HLA alleles (n = 175) with info scores greater than 0.8 and frequencies greater than 0.01 were included (resolution at two-digit level: 71; four-digit level: 104). We studied the associations between HLA alleles and breast cancer risk using logistic regression, adjusting for population structure and age. Associations between HLA alleles and the risk of subtypes of breast cancer (ER-positive, ER-negative, HER2-positive, HER2-negative, early-stage, and late-stage) were examined., Results: We did not observe associations between any HLA allele and breast cancer risk at P < 5e-8; the smallest p value was observed for HLA-C*12:03 (OR = 1.29, P = 1.08e-3). Ninety-five percent of the effect sizes (OR) observed were between 0.90 and 1.23. Similar results were observed when different subtypes of breast cancer were studied (95% of ORs were between 0.85 and 1.18)., Conclusions: No imputed HLA allele was associated with breast cancer risk in our large Asian study. Direct measurement of HLA gene expressions may be required to further explore the associations between HLA genes and breast cancer risk., (© 2022. The Author(s).)

Background: Early detection of breast cancer (BC) through mammography screening (MAM) is known to reduce mortality. We examined the differential effect that mammography has on BC characteristics and overall survival and the sociodemographic determinants of MAM utilization in a multi-ethnic Asian population., Methods: This study included 3739 BC patients from the Singapore Breast Cancer Cohort (2010-2018). Self-reported sociodemographic characteristics were collected using a structured questionnaire. Clinical data were obtained through medical records. Patients were classified as screeners (last screening mammogram ≤ 2 years before diagnosis), non-screeners (aware but did not attend or last screen > 2years), and those unaware of MAM. Associations between MAM behaviour (MB) and sociodemographic factors and MB and tumour characteristics were examined using multinomial regression. Ten-year overall survival was modelled using Cox regression., Results: Patients unaware of screening were more likely diagnosed with late stage (OR stage III vs stage I (Ref) [95% CI]: 4.94 [3.45-7.07], p < 0.001), high grade (OR poorly vs well-differentiated (reference) : 1.53 [1.06-2.20], p = 0.022), nodal-positive, large size (OR >5cm vs ≤2cm (reference) : 5.06 [3.10-8.25], p < 0.001), and HER2-positive tumours (OR HER2-negative vs HER2-positive (reference) : 0.72 [0.53-0.97], p = 0.028). Similar trends were observed between screeners and non-screeners with smaller effect sizes. Overall survival was significantly shorter than screeners in the both groups (HR non-screeners : 1.89 [1.22-2.94], p = 0.005; HR unaware : 2.90 [1.69-4.98], p < 0.001). Non-screeners and those unaware were less health conscious, older, of Malay ethnicity, less highly educated, of lower socioeconomic status, more frequently ever smokers, and less physically active. Among screeners, there were more reported personal histories of benign breast surgeries or gynaecological conditions and positive family history of breast cancer., Conclusions: Mammography attendance is associated with more favourable BC characteristics and overall survival. Disparities in the utility of MAM services suggest that different strategies may be needed to improve MAM uptake., (© 2022. The Author(s).)

Background: Family history, and genetic and non-genetic risk factors can stratify women according to their individual risk of developing breast cancer. The extent of overlap between these risk predictors is not clear., Methods: In this case-only analysis involving 7600 Asian breast cancer patients diagnosed between age 30 and 75 years, we examined identification of high-risk patients based on positive family history, the Gail model 5-year absolute risk [5yAR] above 1.3%, breast cancer predisposition genes (protein-truncating variants [PTV] in ATM, BRCA1, BRCA2, CHEK2, PALB2, BARD1, RAD51C, RAD51D, or TP53), and polygenic risk score (PRS) 5yAR above 1.3%., Results: Correlation between 5yAR (at age of diagnosis) predicted by PRS and the Gail model was low (r=0.27). Fifty-three percent of breast cancer patients (n=4041) were considered high risk by one or more classification criteria. Positive family history, PTV carriership, PRS, or the Gail model identified 1247 (16%), 385 (5%), 2774 (36%), and 1592 (21%) patients who were considered at high risk, respectively. In a subset of 3227 women aged below 50 years, the four models studied identified 470 (15%), 213 (7%), 769 (24%), and 325 (10%) unique patients who were considered at high risk, respectively. For younger women, PRS and PTVs together identified 745 (59% of 1276) high-risk individuals who were not identified by the Gail model or family history., Conclusions: Family history and genetic and non-genetic risk stratification tools have the potential to complement one another to identify women at high risk., (© 2022. The Author(s).)

Background: HER2-low breast cancer (BC) is currently an area of active interest. This study evaluated the impact of low expression of HER2 on survival outcomes in HER2-negative non-metastatic breast cancer (BC)., Methods: Patients with HER2-negative non-metastatic BC from 6 centres within the Asian Breast Cancer Cooperative Group (ABCCG) (n = 28,280) were analysed. HER2-low was defined as immunohistochemistry (IHC) 1+ or 2+ and in situ hybridization non-amplified (ISH-) and HER2-zero as IHC 0. Relapse-free survival (RFS) and overall survival (OS) by hormone receptor status and HER2 IHC 0, 1+ and 2+ ISH- status were the main outcomes. A combined TCGA-BRCA and METABRIC cohort (n = 1967) was also analysed to explore the association between HER2 expression, ERBB2 copy number variation (CNV) status and RFS., Results: ABCCG cohort median follow-up was 6.6 years; there were 12,260 (43.4%) HER2-low BC and 16,020 (56.6%) HER2-zero BC. The outcomes were better in HER2-low BC than in HER2-zero BC (RFS: centre-adjusted hazard ratio (HR) 0.88, 95% CI 0.82-0.93, P < 0.001; OS: centre-adjusted HR 0.82, 95% CI 0.76-0.89, P < 0.001). On multivariable analysis, HER2-low status was prognostic (RFS: HR 0.90, 95% CI 0.85-0.96, P = 0.002; OS: HR 0.86, 95% CI 0.79-0.93, P < 0.001). These differences remained significant in hormone receptor-positive tumours and for OS in hormone receptor-negative tumours. Superior outcomes were observed for HER2 IHC1+ BC versus HER2-zero BC (RFS: HR 0.89, 95% CI 0.83-0.96, P = 0.001; OS: HR 0.85, 95% CI 0.78-0.93, P = 0.001). No significant differences were seen between HER2 IHC2+ ISH- and HER2-zero BCs. In the TCGA-BRCA and METABRIC cohorts, ERBB2 CNV status was an independent RFS prognostic factor (neutral versus non-neutral HR 0.71, 95% CI 0.59-0.86, P < 0.001); no differences in RFS by ERBB2 mRNA expression levels were found., Conclusions: HER2-low BC had a superior prognosis compared to HER2-zero BC in the non-metastatic setting, though absolute differences were modest and driven by HER2 IHC 1+ BC. ERBB2 CNV merits further investigation in HER2-negative BC., (© 2022. The Author(s).)

Phyllodes tumours occurring in pregnancy are very rare. While most cases presented as rapidly enlarging masses, we present a benign phyllodes tumour which had the most growth in the first half of pregnancy followed by gradual growth in the latter half of pregnancy and lactation, as characterised on ultrasound imaging. This is the first report, to the best of our knowledge, which has objective measurements of the lesion before, during and after pregnancy. It also highlighted the need for a vigilant approach to fibroepithelial lesions in pregnancy, instead of attributing the growth of these lesions solely to hormonal changes., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Oncoplastic breast-conserving surgery (OBCS) can cause breast asymmetry. Although contralateral breast surgery to achieve symmetry was offered to these patients, the uptake of symmetrisation was variable. We aimed to determine the factors that deter patients with breast cancer undergoing OBCS from opting for symmetrisation., Methods: All patients with breast cancer who underwent OBCS of displacement type with no symmetrisation were prospectively surveyed to explore the social, economic, psychological and physical reasons against symmetrisation., Results: A total of 28 patients participated in a survey administered at a mean 21.6 (range 2-47) months after OBCS. A combination of factors, such as worry and desire to treat breast cancer first (67.9%), not being overly concerned about breast cosmesis (57.1%) and fear of pain from additional operation (28.6%), deterred patients from immediate symmetrisation. Worry and desire to treat breast cancer first was the most important single factor for 50% of the patients. Reasons for no delayed symmetrisation included not being overly concerned about breast cosmesis (70.4%), fear of breast cancer recurrence (48.1%) and being happy with current breast cosmesis (33.3%), with the former two reasons equally cited as the single most important deterrent by 30% of patients each., Conclusion: A combination of factors may deter patients from symmetrisation. The most significant factors deterring OBCS among patients were worry and desire to treat breast cancer first for immediate symmetrisation, and not being overly concerned about breast cosmesis and fear of breast cancer recurrence for delayed symmetrisation. Reassuring these patients may increase their uptake of symmetrisation, thereby improving patient cosmesis and satisfaction., (Copyright: © Singapore Medical Association.)

Background: Mutations in certain genes are known to increase breast cancer risk. We study the relevance of rare protein-truncating variants (PTVs) that may result in loss-of-function in breast cancer susceptibility genes on tumor characteristics and survival in 8852 breast cancer patients of Asian descent., Methods: Gene panel sequencing was performed for 34 known or suspected breast cancer predisposition genes, of which nine genes (ATM, BRCA1, BRCA2, CHEK2, PALB2, BARD1, RAD51C, RAD51D, and TP53) were associated with breast cancer risk. Associations between PTV carriership in one or more genes and tumor characteristics were examined using multinomial logistic regression. Ten-year overall survival was estimated using Cox regression models in 6477 breast cancer patients after excluding older patients (≥75years) and stage 0 and IV disease., Results: PTV 9genes carriership (n = 690) was significantly associated (p < 0.001) with more aggressive tumor characteristics including high grade (poorly vs well-differentiated, odds ratio [95% confidence interval] 3.48 [2.35-5.17], moderately vs well-differentiated 2.33 [1.56-3.49]), as well as luminal B [HER-] and triple-negative subtypes (vs luminal A 2.15 [1.58-2.92] and 2.85 [2.17-3.73], respectively), adjusted for age at diagnosis, study, and ethnicity. Associations with grade and luminal B [HER2-] subtype remained significant after excluding BRCA1/2 carriers. PTV 25genes carriership (n = 289, excluding carriers of the nine genes associated with breast cancer) was not associated with tumor characteristics. However, PTV 25genes carriership, but not PTV 9genes carriership, was suggested to be associated with worse 10-year overall survival (hazard ratio [CI] 1.63 [1.16-2.28])., Conclusions: PTV 9genes carriership is associated with more aggressive tumors. Variants in other genes might be associated with the survival of breast cancer patients. The finding that PTV carriership is not just associated with higher breast cancer risk, but also more severe and fatal forms of the disease, suggests that genetic testing has the potential to provide additional health information and help healthy individuals make screening decisions., (© 2021. The Author(s).)

Introduction: Supplementary ultrasound surveillance in breast cancer patients can detect additional cancers but is associated with unnecessary biopsies and follow-ups. We aim to determine, in patients with ductal carcinoma in situ (DCIS), the prevalence and factors associated with second breast cancers and the usefulness of supplementary ultrasound surveillance. This is the first study which focused on the usefulness of ultrasound surveillance in DCIS patients., Methods: DCIS patients were retrospectively analyzed to determine the prevalence and factors associated with second breast cancers. The prevalence of patients with benign biopsies, additional ultrasound follow-ups and second breast cancers, resulting from ultrasound surveillance, were calculated., Results: Three hundred and thirty- two patients were included. 25 (7.5%) patients developed second breast cancers after a mean follow-up of 77.7 months. Breast conservation (P= .0218), involved margins after lumpectomy (P = .0003) and shortened hormonal therapy (P= 0.0369) were associated with second cancers. Of the 314 patients who had ultrasound surveillance, ipsilateral, and contralateral ultrasounds yielded 1.7%/1.3% cancer detection, 5.8%/6.7% benign biopsies and 10.4%/15.3% additional follow-ups. Patients with involved margins after lumpectomy have ipsilateral cancer detection, benign biopsies and additional follow-ups of 4.5%, 4.5%, and 9.1% respectively. A total of 85.4% patients had mammographically dense breasts., Conclusion: In DCIS patients, the rate of second breast cancers was 7.5%. Breast conservation, involved margins after lumpectomy and shortened hormonal therapy were associated with second cancers. Patients with involved margins after lumpectomy have the highest cancer detection rate and minimal unnecessary biopsies and follow-ups. Hence, ipsilateral breast ultrasound surveillance could be personalized for this high-risk group with mammographically dense breasts., (Copyright © 2021. Published by Elsevier Inc.)

Purpose: Studies that report equivalent oncologic outcomes of sentinel lymph node biopsy (SLNB) alone versus axillary lymph node dissection (ALND) for T1-2N1mi breast cancers are heavily weighted with patients who received breast-conserving surgery (BCS). The impact of omitting ALND in N1mi patients treated with mastectomy is not well studied. It is also unknown if these patients would benefit from post-mastectomy radiotherapy (PMRT). This study reports the outcomes of patients with T1-2N1mi breast cancer treated by mastectomy without axillary therapy., Methods: Patients who had T1-2N1mi breast cancer and underwent mastectomy from January 1998 to December 2018 were identified from our multi-institutional prospective database. Axillary recurrence rate (ARR), disease-free survival (DFS), and overall survival (OS) are reported., Results: 260 patients with pT1-2N1mi breast cancer who had mastectomy were identified. They had either SLNB (35.4%) or ALND (64.6%). Majority of these patients received adjuvant systemic therapy (93.8%). 77 (29.6%) patients received radiotherapy, 31 after SLNB and 46 after ALND. At median follow-up of 61 months, ARR was 1.1% (n = 1) in the SLNB only group, vs. 0.6% (n = 1) in the ALND group (p = 0.752). DFS and OS were not significantly different between patients with SLNB alone versus ALND (p = 0.40 and p = 0.27, respectively). Among 92 patients who had SLNB only, no DFS or OS difference was observed with the use of PMRT., Conclusion: In T1-2N1mi patients with mastectomy and SLNB, axillary recurrences were rare. No statistically significant differences were noted between patients with SLNB, ALND, or PMRT. Our findings suggest that these patients may be safely treated without axillary therapy., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This article aims to provide a detailed description of the Singapore Breast Cancer Cohort (SGBCC), an ongoing multi-ethnic cohort established with the overarching goal to identify genetic markers for breast cancer risk, prognosis and treatment response, as well as to understand the ethnic differences in disease risk and outcome in an Asian setting. The cohort comprises of breast cancer patients aged 21 years and above from six public hospitals which diagnose and treat nearly 76% breast cancer cases in Singapore. Self-reported data on sociodemographic and lifestyle, reproductive risk factors, medical history and family history of breast or ovarian cancer is collected using a structured questionnaire. Clinical data on tumour characteristics, and treatment modalities are obtained through medical record. Bio-specimens (blood or saliva) is collected at recruitment. Follow-up on survival information is done through routine linkage with the Registry of Births and Deaths. As of 31 December 2016, 7,768 subjects have been recruited to the study with 76% subjects contributed bio-specimens. The SGBCC provides a valuable platform which offers a unique, large and rich resource for new research ideas on breast cancer related phenotypic risk factors and genetic markers., Competing Interests: The authors have declared that no competing interests exist.

Lessons Learned: Removal of sonographically abnormal (up to 3) metastatic clipped nodes, without sentinel lymph node biopsy, could accurately predict axillary status in breast cancer patients receiving neoadjuvant chemotherapy. ypT and the first clipped node status were statistically significant factors for nodal pathologic complete response. This novel approach requires validation in larger studies., Background: In patients who have node-positive breast cancer, neoadjuvant chemotherapy could result in nodal pathologic complete response (pCR) and avoid an axillary lymph node dissection (ALND). Axillary staging, in such cases, can be performed using targeted axillary dissection (TAD) with a low false negative rate. However, identification of sentinel lymph nodes (SLNs) after chemotherapy can be difficult, and currently, it is the standard to remove only one clipped node in TAD. We aimed to determine if removal of all sonographically abnormal metastatic clipped nodes, without SLN biopsy, could accurately predict the axillary status post neoadjuvant chemotherapy., Methods: Patients with breast cancer with one to three sonographically abnormal metastatic axillary nodes were prospectively recruited. Each abnormal node had histology and clip insertion before neoadjuvant chemotherapy. After chemotherapy, the patients underwent removal of clipped nodes using the Skin Mark clipped Axillary nodes Removal Technique (SMART) and ALND., Results: Fourteen patients were recruited, having a total of 21 sonographically abnormal metastatic nodes, with nine, three, and two patients having 1, 2, and 3 malignant nodes clipped, respectively. Mean age was 55.5 years; 92.9% and 57.1% of patients had invasive ductal carcinoma and grade III tumors, respectively; and 35.7% patients achieved nodal pCR. The first clipped node predicted the axillary status with a false negative rate of 7.1%. Adding to this another second clipped node, the false negative rate was 0%. Pathologic tumor staging after neoadjuvant chemotherapy (ypT) (p = .0390) and the first clipped node pathological response status (p = .0030) were statistically significant predictors for nodal pCR., Conclusion: Removal of sonographically abnormal metastatic clipped nodes using SMART, without sentinel lymph node biopsy, could accurately predict axillary status. This finding needs validation in larger studies., (© AlphaMed Press; the data published online to support this summary are the property of the authors.)

Polygenic risk scores (PRS) have been shown to predict breast cancer risk in European women, but their utility in Asian women is unclear. Here we evaluate the best performing PRSs for European-ancestry women using data from 17,262 breast cancer cases and 17,695 controls of Asian ancestry from 13 case-control studies, and 10,255 Chinese women from a prospective cohort (413 incident breast cancers). Compared to women in the middle quintile of the risk distribution, women in the highest 1% of PRS distribution have a ~2.7-fold risk and women in the lowest 1% of PRS distribution has ~0.4-fold risk of developing breast cancer. There is no evidence of heterogeneity in PRS performance in Chinese, Malay and Indian women. A PRS developed for European-ancestry women is also predictive of breast cancer risk in Asian women and can help in developing risk-stratified screening programmes in Asia.

Purpose: Removal of clipped nodes can improve sentinel node biopsy accuracy in breast cancer patients post neoadjuvant chemotherapy (NACT). However, the current methods of clipped node localization have limitations. We evaluated the feasibility of a novel clipped node localization and removal technique by preoperative skin marking of clipped nodes and removal by the Skin Mark clipped Axillary nodes Removal Technique (SMART), with the secondary aim of assessing the ultrasound visibility of the various clips in the axillary nodes after NACT., Methods: Invasive breast cancer patients with histologically metastatic axillary nodes, going for NACT, and ≤3 sonographically abnormal axillary nodes were recruited. All abnormal nodes had clips inserted. Patients with M1 disease were excluded. Post-NACT, patients underwent SMART and axillary lymph node dissection. Specimen radiography and pathological analyses were performed to confirm the clipped node presence. Success, complication rates of SMART, and ultrasound visibility of the various clips were assessed., Results: Twenty-five clipped nodes in 14 patients underwent SMART without complications. The UltraCor Twirl, hydroMARK, UltraClip Dual Trigger, and UltraClip were removed in 13/13 (100%), 7/9 (77.8%), 1/2 (50.0%), and 0/1 (0%), respectively (P = .0103) with UltraCor Twirl having the best ultrasound visibility and removal rate. Removal of three clipped nodes in the same patient (P = .0010) and deeply seated clipped nodes (P = .0167) were associated with SMART failure., Conclusion: Skin Mark clipped Axillary nodes Removal Technique is feasible for removing clipped nodes post-NACT, with 100% observed success rate, using the UltraCor Twirl marker in patients with <3 not deeply seated clipped nodes. Larger studies are needed for validation., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

We evaluate the preoperative breast cancer (BC) characteristics that affect the diagnostic accuracy of axillary ultrasound (US) and determine the reliability of US in the different subgroups of BC patients. Axillary US assessments in women with invasive BC diagnosed between 2009 and 2016 in a single institution were retrospectively reviewed. The diagnostic accuracy of axillary US was obtained using surgical nodal histology as the gold standard. Preoperative breast tumor sonographic and histological factors affecting axillary US diagnostic accuracy were examined. Of the 605 newly diagnosed invasive BC cases reviewed, 251 (41.5%) had nodal metastases. Axillary US sensitivity was 75.7%, specificity 92.9%, positive predictive value 88.4%, negative predictive value 84.4%, and false-negative rate 24.3%. Lower US sensitivity was seen with invasive lobular cancer (ILC) (P = .043), grade I/II, (P = .021), unifocal (P = .039), and smaller tumors (P < .001). US specificity was lower in grade III (P < .001), estrogen receptor (ER)-negative (P < .001), progesterone receptor (PR)-negative (P = .004), HER2-positive (P = .015), triple-negative (P = .001), and larger breast tumors (P < .001). US has moderate sensitivity and good specificity in detecting metastatic axillary lymph nodes. Based on preoperative cancer characteristics, US was less sensitive for nodal metastases from ILC, unifocal, lower grade, and smaller breast tumors. It was also less specific in grade III, ER-negative, PR-negative, HER2-positive, triple-negative, and larger breast tumors. Caution is suggested in interpreting the US axillary findings of patients with these preoperative tumor features., (© 2019 Wiley Periodicals, Inc.)

Competing Interests: Competing interests: None declared.

Virtual simulators have been employed for the teaching of breast surgery. However, there remains no virtual simulator for the training of oncoplastic breast conserving surgery. This is the first known report of virtual simulator for oncoplastic breast conserving surgery training, to the best of our knowledge., (Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

An elderly woman presented with an enlarging left breast lump. Breast imaging revealed a large suspicious mass associated with cystic components. Core biopsy however was non-diagnostic and only revealed necrotic papillary tissue. The patient then underwent excision of the lesion that revealed a large area of intracystic papillary ductal carcinoma in situ with a focus of micropapillary variant of mucinous cancer. This case describes how this rare subtype could present as necrotic papillary tissue on core biopsy, resulting in a diagnostic dilemma, which had not been previously reported. A literature review of this rare subtype was performed too., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Z0011 trial showed that early breast cancer patients with low axillary nodal burden, may be spared an axillary lymph node dissection with no survival compromise. Axillary lymph node dissection can be reserved for patients with a high axillary nodal burden. We aim to determine the preoperative factors that could distinguish between low and high axillary nodal burden in Z0011 eligible patients with a needle biopsy proven metastatic node., Method: Patients who fulfilled Z0011 trial criteria with a positive lymph node needle biopsy and had axillary lymph node dissection (ALND) were recruited. These patients were classified into low and high nodal burden subgroups, defined as having 1-2 and ≥3 metastatic lymph nodes, respectively. The clinical, radiological and pathological features between the 2 subgroups were compared., Results: 70 (40%) and 105 (60%) patients had low and high nodal burden respectively. The high nodal burden subgroup was more likely to have on ultrasound ≥3 abnormal lymph nodes (37.14% versus 4.29%) (P < 0.0001) and maximum cortical thickness >4 mm (31.43% versus 10.0%) (P = 0.0036). Multivariate analysis revealed abnormal lymph nodes ≥3 to have an odds ratio of 20.72 (95% CI 5.91-72.65) P < 0.0001., Conclusion: ≥3 abnormal lymph nodes on ultrasound was the most significant predictor of high nodal burden subgroup in Z0011 eligible patients with a positive lymph node needle biopsy. This information could allow this subgroup to proceed to an upfront ALND and avoid the need of a sentinel lymph node biopsy in the post Z0011 trial era., (Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

An elderly woman, with no clinically palpable breast lump, presented with an initially benign-appearing lesion on ultrasound. She was followed up to reveal the natural history of luminal A breast cancer., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: Reluctance to share hereditary cancer syndrome genetic test results with family is reported among Asian patients. This study aims to explore patient factors influencing result sharing with family, to improve overall testing uptake., Methods: Participants were women with a personal/family history of breast and/or ovarian cancer who received a positive, negative, or variant of uncertain significance test result. In-depth interviews were conducted to theme saturation to explore facilitators and barriers for sharing results with family. Grounded theory with thematic analysis was applied in analysis and interpretation., Results: Twenty-four women participated. Three themes representing facilitators emerged for all results categories: family closeness, involvement of families in the testing process, and perception of low emotional impact of results. In the positive result category, 2 facilitator themes emerged: presence of actionable results and perception of family members' acceptance. In the negative and variant of uncertain significance result categories, 2 themes representing barriers to sharing emerged: perception of no genetic or medical implication for family and result ambiguity., Conclusion: Facilitators and barriers for result sharing are similar to those among Western women. A framework to explain Asian patients' decision-making process identifies optimal counselling opportunities to enhance communication with family., (Copyright © 2018 John Wiley & Sons, Ltd.)

Invasive papillary carcinoma of the breast and Paget's disease are both rare entities. We report the first known case of invasive papillary carcinoma associated with Paget's disease in a woman who presented clinically with a nipple mass. While invasive papillary carcinoma has been reported to have an indolent course without need for overtreatment, our patient had unusual unfavourable histological features. Literature review of this rare subtype was performed., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

We aim to identify clinicopathologic predictors for response to neoadjuvant chemotherapy and to evaluate the prognostic value of pathologic complete response (pCR) on survival in Asia. This study included 915 breast cancer patients who underwent neoadjuvant chemotherapy at five public hospitals in Singapore and Malaysia. pCR following neoadjuvant chemotherapy was defined as 1) no residual invasive tumor cells in the breast (ypT0/is) and 2) no residual invasive tumor cells in the breast and axillary lymph nodes (ypT0/is ypN0). Association between pCR and clinicopathologic characteristics and treatment were evaluated using chi-square test and multivariable logistic regression. Kaplan-Meier analysis and log-rank test, stratified by other prognostic factors, were conducted to compare overall survival between patients who achieved pCR and patients who did not. Overall, 4.4% of nonmetastatic patients received neoadjuvant chemotherapy. The median age of preoperatively treated patients was 50 years. pCR rates were 18.1% (pCR ypT0/is) and 14.4% (pCR ypT0/is ypN0), respectively. pCR rate was the highest among women who had higher grade, smaller size, estrogen receptor negative, human epidermal growth factor receptor 2-positive disease or receiving taxane-based neoadjuvant chemotherapy. Patients who achieved pCR had better overall survival than those who did not. In subgroup analysis, the survival advantage was only significant among women with estrogen receptor-negative tumors. Patients with poor prognostic profile are more likely to achieve pCR and particularly when receiving taxane-containing chemotherapy. pCR is a significant prognostic factor for overall survival especially in estrogen receptor-negative breast cancers., (© 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Introduction: While overexpression of syndecan-1 has been associated with aggressive breast cancer in the Caucasian population, the expression pattern of syndecan-1 in Asian women remains unclear. Triple-positive breast carcinoma, in particular, is a unique subtype that has not been extensively studied. We aimed to evaluate the role of syndecan-1 as a potential biomarker and prognostic factor for triple-positive breast carcinoma in Asian women., Methods: Using immunohistochemistry, staining scores of 61 triple‑positive breast carcinoma specimens were correlated with patients' clinicopathological variables such as age, ethnicity, tumour size, histological grade, lymph node status, lymphovascular invasion, associated ductal carcinoma in situ grade, recurrence and overall survival., Results: Syndecan-1 had intense staining scores in triple‑positive invasive ductal breast carcinomas when compared to normal breast tissue. On multivariate analysis, syndecan-1 epithelial total percentage and immunoreactivity score showed statistical correlation with survival (p = 0.02)., Conclusion: The intense staining scores of syndecan-1 and their correlation with overall survival in patients with triple-positive breast carcinoma suggest that syndecan-1 may have a role as a biological and prognostic marker in patients with this specific subtype of breast cancer.

Breast ductal carcinoma in situ (DCIS) is a preinvasive form of breast cancer. It typically presents as microcalcifications which are picked up on screening mammogram. We report an atypical case of breast DCIS presenting with recurrent non-puerperal mastitis with a normal mammogram and perform a literature review.