Long-Standing Breast Mass in an Elderly Male: A Rare Case of Invasive Papillary Carcinoma.

Multidisciplinary considerations in the treatment of triple-negative breast cancer.

Breast carcinoma is uncommon in males and constitutes less than one per cent of all cancers in men. Invasive papillary carcinoma is a rare morphological type of breast cancer. Since papillary carcinoma has a favorable prognosis as compared to other histopathological subtypes, an accurate diagnosis is essential. We report two cases of this rare histological type of male breast cancer. A 62-year-old man presented with a lump in the central quadrant of right breast and underwent simple mastectomy. Histological examination showed features of invasive papillary carcinoma. The other case was of an 81-year-old male patient with a subareolar mass in the right breast. Wide local excision of the lump showed features of an intracystic invasive papillary carcinoma. The patient subsequently underwent simple mastectomy, however, no residual tumor was found in the resection specimen. Both the patients were free of disease at one year of follow-up. Invasive papillary carcinoma is an uncommon morphological type of breast cancer in males. The intracystic variant of papillary carcinoma is extremely unusual and may be missed on cytological examination. A thorough sampling is essential for an accurate diagnosis of invasion in these cases.

Male breast cancer is a rare neoplasm, accounting for approximately 1% of all breast cancer cases. It typically presents as a painless, retroareolar mass. An exceedingly rare variant is male occult breast cancer, which is primarily characterized by axillary lymph node enlargement without an identifiable primary breast tumor. We report an intriguing case of a septuagenarian patient diagnosed with male occult breast cancer. The patient presented with both axillary lymph node enlargement and an associated axillary skin ulcer, and was subsequently diagnosed with male occult breast cancer with metastases to the axillary and clavicular lymph nodes, as well as more distant sites. His treatment involved a multidisciplinary approach, including HER2-targeted therapy, chemotherapy, axillary lymph node dissection, and radiotherapy. Regular follow-ups have shown that his condition remains stable. Notably, this is the first documented case of male occult breast cancer with distant metastasis that was successfully treated with surgery and radiotherapy following systemic therapy. This case highlights the complex clinical presentation and management of male occult breast cancer. Our findings suggest that surgical intervention may be a feasible option post-downstaging by systemic therapy, even in the presence of distant metastases.

Objective: Male breast cancer (MBC) is a rare disease, accounting for less than 1% of breast and male cancers. Because of the low incidence, most of the clinical decisions for MBC have been derived from the experience of treatment of breast cancer in females. MBC is generally detected in advanced stages due to a lack of social awareness as it occurs in breast cancer in females. In this study, it was aimed to compare our clinical experience with MBC with current literature. Methods: This study retrospectively reviewed 21 men who were diagnosed with MBC between January 2008 and January 2018 at the Department of General Surgery of Mersin University School of Medicine, Mersin, Turkey. Results: Unilateral malign breast lesions were identified in 21 male patients that 17 are primary MBC and 4 metastatic breast lesions. 15 primary MBC patients underwent primary surgical treatment, and 2 patients were directed to neoadjuvant treatment. Simple mastectomies were performed in most surgical cases. 7 patients were directly addressed to axillary lymph node dissection (ALND), and sentinel lymph node biopsy (SLNB) was performed in 8 patients. 4 patients had tumor positivity in the settings of SLNB, and further ALND was performed subsequently in these cases. None of the patients developed local recurrence in the 24-month follow-up (range 6-96 months). Conclusion: The rarity of MBC precludes randomized clinical trials. Most of the clinical decisions for MBC have been derived from the experience of treatment of breast cancer in females. Further studies are needed to understand better MBC.

Background: Male breast cancer (MaBC) is rare, comprising <1% of all breast cancers in the United States. The low incidence of MaBC limits the ability to conduct clinical trials specifically for this population. Due to the paucity of research on MaBC, current understanding regarding MaBC biology, pathology, and treatment strategies has been primarily based on evidence extrapolated from research on female breast cancer (FBC) patients. Traditional diagnostic biomarkers such as ER, PR, and HER2, as well as newer multi-gene prognostic signatures, are employed when making treatment decisions for both MaBC and FBC. However, limited empirical data is available to support the use of identical laboratory biomarkers and molecular signatures in both MaBC and FBC. The 70-gene risk of distant recurrence signature, MammaPrint (MP), and the 80-gene molecular subtyping signature, BluePrint (BP), are commonly used to help make treatment decisions for both MaBC and FBC patients. To support the clinical utility of MP and BP in MaBC, this study aims to elucidate whether significant molecular biological differences exist between MaBC and FBC. To address this knowledge gap, we evaluated and compared 1) MP index results within Low Risk (LR) and High Risk (HR) groups, 2) MP and BP gene expression, and 3) differentially expressed genes within the full genome and their associated biological pathways between tumors from MaBC and FBC. Methods: This analysis included a total of 817 breast tumor samples sent to Agendia, Inc. (Irvine, CA) for MP and BP testing. Full-transcriptome microarray data were available for 1) a subset of 400 post-menopausal FBC patients enrolled in the FLEX Registry (NCT03053193) and 2) 80 MaBC pateints, 32 of whom enrolled in the FLEX registry and 48 non-study patients for whom data were limited to metadata and quality metrics routinely captured for diagnostic testing. Data from all patients were de-indentified. Differences in mean MP indices between FBC (N=400) and MaBC (N=417) according to MP Risk classification (LR or HR) were analyzed using a Z-test. Differential gene expression analysis was performed using the R-limma package in which gene expression data were quantile normalized. Pathway analyses were performed using GOseq. Differentially expressed genes (DEGs) were identified between FBC (N=400) and MaBC (N=80) for whom full transcriptome microarray data were available. DEGs were defined as those with a fold change of > 2 and an adjusted P value of < 0.05. Results: All patients in this study had hormone positive, HER2 negative early-stage breast cancer. There was no statistical difference in the average MP index between MaBC and FBC classified as MP LR (P=0.273) or those classified as MP HR (P=0.692). Gene expression comparison revealed 166 DEGs between MaBC (N=80) and FBC (N=400), 99 DEGs between MP HR MaBC (N=42) and MP HR FBC (N=200), and 290 DEGs between MP LR MaBC (N=38) and MP LR FBC (N=200). Pathway analyses revealed that downregulated genes in MaBC compared to FBC enriched to immune-related functions, including B-cell mediated immunity, whereas upregulated genes were associated with hormone metabolic processes. In all comparisons, expression of MP or BP genes was not significantly different. Conclusions: We found similar MP index distributions between MaBC and FBC. Importantly, differential gene expression between MaBC and FBC provides novel insight into the mechanisms underlying MaBC. Although these data reveal biological distinctions between male and female breast cancer, MP and BP assay performance is preserved across both groups. Further studies are needed to assess clinical outcomes; however, these findings support the use of MP risk of recurrence assay and BP molecular subtyping assay for prognosis and informing treatment decisions in MaBC. Citation Format: Jennifer Crozier, Julie Barone, Kalyan Banda, Beth Lesnikoski, Robert Maganini, Sami Diab, Ian Grady, Thomas Lomis, Charles Cox, Amy Truitt, Benjamin Nota, Andrea Menicucci, Erin Yoder, William Audeh, FLEX Investigators Group. Differential gene expression analysis and clinical utility of MammaPrint and BluePrint in male breast cancer patients [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 PS14-11.

Introduction: Due to the low incidence of male breast cancer, large scale prospective trials to guide therapy are lacking. Historically males with breast cancer present at more advanced stages than females and have been surgically treated with modified radical mastectomy. Recent studies suggest that breast-conserving therapy for early-stage male breast cancer yields similar outcomes as for female patients, and that sentinel lymph node biopsy (SLNB) can be used in place of axillary lymph node dissection (ALND) for appropriate clinically node-negative patients. Our study investigates trends in breast and axillary surgery for male breast cancer patients, focusing specifically on the treatment of early-stage disease. Methods: The National Cancer Database (NCDB) was utilized to identify male and female patients diagnosed with clinical T1-2 breast cancer from 2004-2016. Patient, tumor, facility, and surgical treatment factors were examined. Patients were stratified by surgery type: partial, unilateral, and bilateral mastectomy; simple versus modified radical mastectomy; SLNB (removal of ≤ 5 lymph nodes) and ALND (>5 lymph nodes). Trends in surgery type were compared between male and female patients and over the study period for each gender. Results: 9,782 males and 1,078,105 females with T1-2 breast cancer were identified. Men were significantly older at diagnosis than women (31.4% vs. 23.6% age >70, p<0.0001), were more often insured by Medicare (44.5% vs. 35.3%, p<0.0001), and had greater co-morbidity (21.9% vs. 15.6% Charlson Deyo Score >0). ER/PR+ disease (94.2% vs. 84.1%, p<.0001), moderate/high grade histology (85.4% vs. 77.8%, p<.0001) and lymphovascular invasion (24% vs. 15.3%, p<.0001) were also more common in males vs. females. The majority of all patients were clinically node negative (80.4% of males, 85% of females) and had AJCC clinical stage I or II disease (92.3% men, 95.2% women). Unilateral mastectomy was performed most commonly for men (67.1% men vs. 24.1% women, p<0.001), while women more frequently underwent partial mastectomy (64.7% women vs. 26.4% men, p<0.001). The rates of each surgery type remained disparate by gender and stable over the study period: male unilateral mastectomy rate 59.8% in 2004 and 66.1% in 2016; female partial mastectomy rate 65.9% in 2004, 68.4% in 2016. Modified radical mastectomy rates decreased in favor of simple mastectomy for both genders, 61.8% to 24.1% in males and 58.7% to 20.2% in females, 2004 to 2016. There was a similar overall increase in SLNB vs. ALND for all patients, though SLNB was not adopted as the more common procedure in male patients until 2009. In 2016, 78.2% of females and 65.3% of males underwent SLNB vs. 51.1% and 39.8% in 2004, respectively. Conclusions: Although breast-conserving therapy is the treatment of choice for female patients with early-stage breast cancer and could be similarly used to treat men with T1-T2 disease, the majority of male breast cancer patients continue to undergo unilateral mastectomy for early-stage disease. In more recent years, SLNB has surpassed ALND for men, mirroring the trend for women, though in a more delayed and gradual fashion. Partial mastectomy and SLNB warrant consideration for men with T1 and T2 breast cancer, in particular since male breast cancer patients present at older ages and with more co-morbidity than their female counterparts, and may benefit from de-escalation of surgical treatment. Citation Format: Rashi Singh, Lifen Cao, Anuja L Sarode, Michael Kharouta, Robert Shenk, Megan E Miller. Trends in breast and axillary surgery for T1-T2 male breast cancer: A study from the national cancer database [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 PS14-12.

587 Background: The incidence of MBC continues to rise. Few studies have addressed the differences between MBC and female breast cancer (FBC). Treatment for MBC has ben extrapolated from FBC regimens. The VA cancer registry (VACCR) provides a unique source to study MBC. This retrospective analysis aims at comparing the characteristics and outcome of MBC and FBC in the VA population. Methods: We reviewed the VACCR database between 1995 and 2005, for 120 VA medical centers. Primary breast cancer site codes were identified (500–508). Data was entered and analyzed using bio-statistical software SPSS. Results: A total of 3025 patients :612 MBC and 2413 FBC were compared. Mean age at diagnosis was 67 for MBC and 57 for FBC (p <0.005). More MBC patients were black. MBC patients presented with a significantly higher stage of disease, more node positive(N+) and larger tumor size. In MBC, ductal histology was more common while lobular and ductal carcinoma in situ were less common than in FBC. ER + and PR + tumors were significantly more common in MBC (60% vs 52% and 53% vs 47%, P< 0.005). MBC patients received less chemotherapy while no statistical difference in hormonal treatment was observed. The median overall survival (OS) was lower for MBC (7 years vs 9.8 years, p<0.005). OS was not significantly different for stage III and IV while OS was inferior for MBC in stage I (7 yr vs not reached, p 0.005) and stage II (6 vs 8.6yr, p 0.001). In N- tumors, OS was inferior in MBC (6.1 vs 14.6 yr, p<0.005) but not statistically different for N+ tumors . In ER + and PR + tumors, OS was inferior in MBC (7yr vs 8yr and 7.3 yr vs 9.8 yr p<0.005); however, no statistical significance was observed in ER - or PR - tumors. Using Cox regression analysis age, sex, clinical stage, nodal status were statistically independent prognostic factors while race, histology and grade were not. Conclusion: This study suggests differences in the biology, pathology, presentation, and survival between male and female VA breast cancer patients. Survival of MBC patients appears inferior in early stage disease and N- tumors suggesting gender differences in the tumor pathogenesis and biology. In hormone receptor + MBC, survival was also inferior despite similar hormonal treatment practices. This observational study calls for different approach and treatment strategies in MBC. No significant financial relationships to disclose.

539 Background: Male BC accounts for < 1% of all BC and is often diagnosed at later stage, which can result in higher mortality. Due to the rarity of this diagnosis, limited data exist on genomic alterations and prevalence of cancer susceptibility genes (CSG). We aimed to comprehensively describe the genomics of male BC and compare these to a FBC cohort across subtypes to provide insight on tumor biology and opportunities for targeted therapies. Methods: 275 male BC TBx or LBx were sequenced by Foundation Medicine (FM) using hybrid capture-based CGP. Both TBx and LBx were evaluated for all classes of genomic alterations (GA). Histological subtype, receptor status, and biopsy site were extracted from pathology reports. Paired samples with both TBx and LBx were available in 7 cases. The male BC TBx cohort with known receptor status (n = 253) was compared to a FBC cohort (n = 2855). Mutational prevalence in 5 breast CSG (ATM/BRCA1/BRCA2/CHEK2/PALB2) were compared along with their associated genomic LOH (gLOH) values. Results: Among male BCs, subtype distribution was: ER+/HER2- n = 210 (83%), ER+/HER2+ n = 22 (9%), TNBC n = 20 (8%). ER+/HER2+ male BC cases had higher rates of ERBB2 SV (22.7% v. 0.62%, p < 0.0001), PIK3CA (68.2% vs. 34%, p = 0.01), MDM2 amplifications (36% v. 4%, p < 0.0001) and GATA3 (36.6% v. 6.2%, p = 0.0002) than ER+/HER2+ FBC. In the ER+/HER2- cohort, male BC had more alterations in BRCA2 (13.8% v. 5.3%, p < 0.0001) and GATA3 (26% vs. 15%, p = 0.0004) and less alterations in TP53 and ESR1 (p < 0.0001 both). 28.6% of male BC v. 16.6% of FBC (p = 0.004) had one or more variants in one of 5 CSG of potential germline origin with a higher % of BRCA mutations in male BC vs. FBC (17.5% v. 9.9%, p = 0.0006). In the paired male BC Bx’s we saw genomic heterogeneity in a case showing 5 unique ESR1 alts and a PIK3CA SV unique to LBx done at the same time as TBx. We saw evidence of resistance with a shared BRCA1 alteration and several reversion mutations unique to LBx taken 471 days later, and a longitudinal pair with unique ESR1,PIK3CA and MTOR mutations in a LBx 547 days apart. Conclusions: Although male and female BC share some common alterations, our study revealed potentially important findings that may explain biological differences and provide treatment opportunities. Despite HR+/HER2+ male BC being rare, it was notable for increased co-mutations with ERBB2 SV, PIK3CA SV, and GATA3 SV, which can be associated with a worse prognosis but perhaps allow more novel combinations. ESR1 mutations appear more common in ER+/HER2- FBC reflective of treatment with aromatase inhibitors versus tamoxifen for male BC. TP53 mutations were more common in all subtypes of FBC. BRCA2 mutations and other potential germline CSG variants were more common in male BC, suggesting an opportunity for PARP inhibitors. LBx identified additional biomarkers and resistance mutations not seen in TBx.

Purpose: Male breast cancer (MBC) is extremely rare, accounting for less than 1% of all malignancies in men and only 1% of all breast carcinomas. The treatment and surveillance guidelines on male breast cancers are less recognized. The aim of this study is to evaluate our single institution's experience with MBC over the past 15 years and to contrast differences between female and MBC. Methods: MBC diagnosed from 1994 to 2010 at the Department of Surgery, Samsung Medical Center (Seoul, Korea) was retrospectively analyzed. Clinical data and tumor characteristics were examined. Each MBC was matched with female counterparts by 1:N varied matching ratio that showed accordance in seven variables (year of diagnosis, age, tumor stage, nodal stage, tumor grade, estrogen receptor(ER), progesterone receptor(PR)). Results: 39 male/184 female matched-pairs were available for analysis. The median duration of follow-up was 3.8 years. The median age of MBC patients was 50 years and the median size of tumor was 2.0cm. The proportion of positivity of ER and PR status was 97.4% and 84.6%, respectively. Despite of higher positive rate of hormone receptor, the rate of hormone therapy in MBC patients was significant lower than female conterpart (p = 0.002). Men and women with breast cancer had similar disease-free survival (DFS) and disease-specific overall survival (DSS). Five MBC patients had a recurrence during follow up period and 4 of them were expired. The 10-years DFS was 73.1% in men and 80.5% in women (p = 0.348). The 10-years DSS was 74.1% in men and 87.1% in women, respectively (p = 0.207). Conclusion: This study showed no disease free and overall survival differences between male and female breast cancer patients and revealed that gender is no predictor for survival in breast cancer. Male patients receive obviously less adjuvant treatment compared their female matched patients. It would be better to do more aggressive treatment in MBC to improve the survival outcome. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-11-01.

IntroductionMale breast cancer accounts for 0.5–1% of all breast cancers and is generally diagnosed at higher stage than female breast cancers and therefore might benefit from earlier detection and targeted therapy. Except for HER2 and EGFR, little is known about expression of growth factor receptors in male breast cancer. We therefore investigated expression profiles of growth factor receptors and membrane-bound tumor markers in male breast cancer and gynecomastia, in comparison with female breast cancer.MethodsTissue microarrays containing 133 male breast cancer and 32 gynecomastia cases were stained by immunohistochemistry for a panel of membrane-bound targets and compared with data on 266 female breast cancers.ResultsGrowth factor receptors were variably expressed in 4.5% (MET) up to 38.5% (IGF1-R) of male breast cancers. Compared to female breast cancer, IGF1-R and carbonic anhydrase 12 (CAXII) were more frequently and CD44v6, MET and FGFR2 less frequently expressed in male breast cancer. Expression of EGFR, HER2, CAIX, and GLUT1 was not significantly different between male and female breast cancer. Further, 48.1% of male breast cancers expressed at least one and 18.0% expressed multiple growth factor receptors. Since individual membrane receptors are expressed in only half of male breast cancers, a panel of membrane markers will be required for molecular imaging strategies to reach sensitivity. A potential panel of markers for molecular imaging, consisting of EGFR, IGF1-R, FGFR2, CD44v6, CAXII, GLUT1, and CD44v6 was positive in 77% of male breast cancers, comparable to female breast cancers.ConclusionsExpression patterns of growth factor receptors and hypoxia membrane proteins in male breast cancer are different from female breast cancer. For molecular imaging strategies, a putative panel consisting of markers for EGFR, IGF1-R, FGFR2, GLUT1, CAXII, CD44v6 was positive in 77% of cases and might be considered for development of molecular tracers for male breast cancer.

e12549 Background: Over the last several decades, the mortality for breast cancer has improved, however, there remains a large gender disparity with male patients having worse overall survival. Recent studies have identified increased mortality in male breast cancer (MBC) despite adjusting for age and other clinical factors necessitating a need to evaluate both screening and treatment patterns for MBC. The survival trends in MBC have not been studied across the VA population. Methods: Male and female breast cancer cases between 2000-2018 were identified in National VA Cancer Cube Registry. A total of 1511 cases of MBC and 8081 cases of female breast cancer (FBC) were identified. IRB approval was obtained. Statistical significance was set to 0.05, with significant results noted with an asterisk (*). Results: Our data showed that the number of new MBC cases per year remained stable over the study period while the FBC cases rose by 13.6* per year. The racial distribution of Caucasian and African American (AA) patients was comparable among the two groups. For FBC, the peak incidence was between ages 50-60, while for MBC, the peak incidence was at age greater than 70 years. Males were more likely to present at a later disease stage (stage III and IV) compared to females, (26.94% vs 13.8%) *. They also had a worse performance status (ECOG 3 or higher) at presentation compared to female patients, (3.72% vs 1.32%) *. The survival characteristics and first course of treatment received are summarized in the table below. Our findings show that males have a worse 5-year survival both in early and late-stage disease and across both Caucasian and AA races. This poor survival difference remains when comparing MBC patients older than 50 years but not when comparing the younger subset in both groups. These findings suggest that the overall poor survival of MBC may be related to late detection, advanced age at presentation and subsequent increased comorbidities and poor performance status. Conclusions: Patients with MBC present at a later disease stage and have a worse overall survival when compared to FBC. This difference in survival remained when stratified by age, race and stage at presentation. These results imply the possible underutilization of screening in males as well as differences in the clinical and pathological behavior of male and female breast cancer.[Table: see text]

Background: Hormone receptor–positive/human epidermal growth factor receptor 2–negative (HR+/HER2−) breast cancer (BC) is more prevalent in male patients compared to female counterparts. Gender associated differences along with molecular differences, immune system, and other factors might play a crucial role in disease management. Here, we characterized molecular and immune differences between HR+/HER2- MaBC and FeBC. Methods: 8156 female (HR+/HER2-, n = 5232) and 121 male (HR+/HER2-, n = 97) BC samples were analysed by next-generation sequencing (NextSeq; WES, NovaSeq) and Whole Transcriptome Sequencing (WTS; NovaSeq) (Caris Life Sciences, Phoenix, AZ). Tumor mutational burden (TMB) (high ≥10 mt/MB) was calculated. Microsatellite-instability (MSI) was tested by IHC and NGS. Statistical significance was determined using chi-square and Mann-Whitney U test with p-values adjusted for multiple comparisons (q < 0.05). Results: The proportion of HR+/HER2- subtype was significantly higher in MaBC (80.17% vs 64.14%, p<0.05) compared with FeBC. HR+/HER2- MaBC had higher frequency of BRCA2 (10.64% vs 4.38%, p<0.05), GATA3 (22.68% vs 14.11%, p<0.05), but lower frequency of TP53 (3.45% vs 30.76%, q<0.05), ESR1 (4.12% vs 13.62%, p<0.05) and CDH1 (1.06% vs 17.43%, q<0.05) compared to HR+/HER2- FeBC. Compared to HR+/HER2- FeBC, MaBC had lower frequency of TMB-high (2.2% vs 9.08%, p<0.05), but there was no difference in dMMR/MSI-high (0% vs 0.61%, p=1) or PD-L1 (IHC, 22C3) positivity (21.21% vs 19.47%, p=0.72). HR+/HER2- MaBC had lower expression of AR-RNA (fold change (FC): 1.4, q<0.05), higher AR-protein (IHC) positivity (97.94% vs 84.03%, q<0.05), but no difference was noted in the frequency of fusion variant-AR (1.04% vs 3.19%, p=0.37) compared to FeBC. HR+/HER2- MaBC had increased expression of MHC class I gene HLA-B (FC: 1.2, p<0.05), MHC class II gene HLA-DQB2 (FC: 1.6, q<0.05), but decreased expression of drug efflux gene ABCC2 (FC: 1.4, q<0.05), and stem cell-related genes (KLF4, SOX2, POU5F1, PROM1, ALDH1A1, FC: 1.3-1.9, q<0.05) compared to HR+/HER2- FeBC. Conclusions: These data indicate that HR+/HER2- MaBC has a differential mutational spectrum and TMB-high frequency, MHC Class I and MHC class II, drug efflux and stem cell-related gene expression compared to their HR+/HER2- FeBC counterparts. These suggest important differences in tumor biology between men and women with HR+/HER2- breast cancer. A better understanding of these differences with additional research may help in design future clinical trials and treatments for men with HR+/HER2- BC. Citation Format: Dario Trapani, Sachin Kumar Deshmukh, Sharon Wu, Joanne Xiu, Pooja Advani, Daniel L. Abravanel, Nancy U. Lin, Giuseppe Curigliano, William Flood, Stephanie L. Graff, Maryam Lustberg, Philip Spanheimer, George W. Sledge, Sara M. Tolaney, Jose P. Leone. Molecular landscape of HR+/HER2- male breast cancer (MaBC) compared with female breast cancer (FeBC) [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P1-01-16.

Introduction:Breast cancer incidence in males is rare. MBC remains understudied and treatment recommendations are generally extrapolated from larger trials in women. Characteristics and incidence of the disease vary widely between countries. Tawam Hospital has been the first and the major provider of cancer care in The UAE for over four decades. The epidemiology and characteristics of MBC in The UAE is rather unknown to date. Objective:This study was conducted to investigate the incidence, clinical presentation, pathological characteristics, and treatment patterns of MBC at the major cancer center in the UAE, Tawam Hospital. This will provide a better insight in local features and enables comparison of The UAE data with other parts of the world. Method: We retrospectively analyzed data of MBC treated at The Tawam Hospital between 2000 and 2020. Information was obtained from The Tawam Hospital Cancer Registry and analyzed using excel software.Results:A total of 28 patients with MBC were identified. Male breast cancer consists of 0.75% (28 out of 3733 cases) of all breast cancer cases diagnosed between 2000 - 2020 at the Tawam Hospital. The clinical and the pathological characteristics of these patients are provided in table 1. Only 10 (35%) patients had germline genetics testing and 2 had pathogenic mutation in BRCA1/2 genes. All of the patients presented with palpable mass. Majority of the patients had Grade 2 (57%) or Grade 3 (29%) disease and 15 (54%) had positive lymph nodes at the time of diagnosis. Of the 28 patients, 2 presented with de novo metastatic disease and 26 presented with localized disease. Out of these 26 patients, 22(85%) underwent modified radical mastectomy, 4(15%) had lumpectomy , 17(65%) had axillary lymph node dissection, 9(35%) had sentinel lymph node biopsy, 16(61.5%) had adjuvant radiation therapy, 16(61.5%) had adjuvant chemotherapy and hormonal therapy, 7(27%) had adjuvant hormonal therapy only and 3(11.5%) did not receive adjuvant systemic therapy (2 refused and 1 with hormonal receptor negative DCIS). All of the patients who received hormonal therapy had tamoxifen. about 60% of the patients with localized disease received multimodality treatment including all surgery, radiation therapy and systemic therapy.Recurrent metastatic disease developed in 19% (5 out 26) of the patients. Out of 7 MBC with de novo and recurrent metastatic disease, 3 had bone metastases only, 3 had bone and visceral metastases and 1 was with locoregional recurrence.Conclusion:Our cohort indicates that the majority of the patients with MBC presented with higher grade, cT2 and above and node positive disease indicating the need for better awareness for early detection. Majority of the patients with localized disease received multimodality treatments. Patient outcome of this cohort will be presented at the meeting. Table 1.Clinical and Pathological Characteristics of Male with Breast cancer (N=28)N(%)N(%)Median age51 (33 - 65)–Hormonal receptor/HER-2 status+/+5 (18)Clinical stage04 (14)+/-21 (75)I2 (7)-/+1 (3.5)II12 (43)-/-1 (3.5)III8 (29)GradeI4 (14)IV2 (7)II16 (57)Clinical node statusN013 (46.2)III8 (29)N17 (26)HistologyDCIS24 (86)N24 (14)IDC4 (14)N34 (14)Clinical T statusT0/is4 (14)T13 (11)T215 (54)T32 (7)T44 (14) Citation Format: Aydah Al-Awadhi, Ali Yousif, Nahed Balalaa, Ernest Luiten, Danijela Jelovac. Incidence, clinicopathological features and treatment patterns of male breast cancer (MBC) in a high-volume cancer center in the United Arab Emirates (UAE) [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 P1-23-02.

Sentinel lymph node biopsy (SLNB) is currently used as a routine treatment for patients with breast cancer. However, it may not be applicable for patients with male breast cancer (MBC), because they have notably different clinicopathological features from those occurring in females. There is a lack of evidence of SLNB application and safe exemption from axillary lymph node dissection (ALND) in patients with MBC. This study aimed to evaluate the application of SLNB to provide information for the standardized treatment of patients with MBC. The MBC patient records from 4 institutions ranging from January 2001 to November 2020 were retrospectively reviewed. There were 220 patients with MBC with a median age of 60 (range 24-88) years and an average tumor size of 2.3 cm (range 0.5 cm-6.5 cm). Sixty-six percent of patients underwent SLNB, and 39% of them showed positive results. A total of 157 patients underwent ALND, while only half of them had positive nodes, causing unnecessary complications. For patients in the clinical early stage, we found that the SLNB showed a noninferiority to the ALND treatment in DFS (P = .18) and OS (P = .055). In conclusion, there are certain obstacles to the broad application of SLNB due to the lower proportion of patients with clinically negative lymph nodes. However, it is undeniable that SLNB can safely and effectively exempt patients with MBC at early stage with clinically negative nodes from ALND to reduce subsequent complications. It is still an ideal criterion for the axillary staging of patients with MBC.

Objective:Sentinel lymph node biopsy (SLNB) is currently used as a routine treatment for breast cancer patients. Many clinical studies, such as the NSABP B-32, have demonstrated that SLNB can safely replace axillary lymph node dissection (ALND) for patients with clinically node-negative breast cancer. However, it may not be applicable for male breast cancer (MBC) patients because they have notably different clinicopathological features from those occurring in females. There is a lack of evidence of SLNB application and safe exemption from ALND in MBC patients. This study aimed to evaluate the application of SLNB to provide information for the standardized treatment of MBC patients. Methods:The MBC patient records from four institutions ranging from January 2001 to November 2020 were retrospectively reviewed. Patients undergoing surgery as a primary treatment were included. Patients with stage IV and non-primary breast cancer were excluded. Patients were followed up postoperatively for survival analysis. The primary outcome was disease-free survival (DFS), and the secondary outcome was overall survival (OS). Results:There were 220 MBC patients with a median age of 60 (range 24-88) years and an average tumor size of 2.3 cm (range 0.5 cm - 6.5 cm). MBC patients were characterized by old age, advanced stage, and higher pathological grade. The median follow-up time was 5.0 (range, 1.0-17.3) years. Survival analysis showed the 5-year DFS and OS were 73.5% and 83.3%, respectively. 66 patients (30%) underwent SLNB and 39% of them showed positive results. 157 patients (71%) underwent ALND, while only half of them had positive nodes, causing unnecessary complications. For 92 patients at clinical early-stage (stage I or IIA), 28 patients only had SLNB as axillary treatment, 26 patients only had ALND and 38 patients underwent SLNB and ALND. From Kaplan-Meier survival analysis, we found that the SLNB showed a non-inferiority to the ALND treatment in DFS (p=0.18) and OS (p=0.055). Conclusion:MBC patients are older at the time of diagnosis and present a higher pathological grade. There are certain obstacles to the broad application of SLNB due to the lower proportion of clinically-negative lymph node patients. However, it is undeniable that SLNB can safely and effectively exempt MBC patients at early-stage with clinically-negative nodes from ALND to reduce subsequent complications. It’s still an ideal criterion for the axillary staging of MBC patients. Clinicopathologic characteristics of MBC patients Citation Format: Qingyao Shang, Ya Wei, Guangdong Qiao, Jingruo Li, Xin Wang. Evaluation of male breast cancer and the application of sentinel lymph node biopsy: A multi-center retrospective study [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 P2-14-22.