Adjuvant treatment of early male breast cancer

Whole-Genome Sequencing Analysis of Male Breast Cancer Unveils Novel Structural Events and Potential Therapeutic Targets

The molecular characterization of male breast cancer (MaBC) has received limited attention in research, mostly because of its low incidence rate, accounting for only 0.5% to 1% of all reported cases of breast cancer each year. Managing MaBC presents significant challenges, with most treatment protocols being adapted from those developed for female breast cancer. Utilizing whole-genome sequencing (WGS) and state-of-the-art analyses, the genomic features of 10 MaBC cases (n = 10) were delineated and correlated with clinical and histopathologic characteristics. Using fluorescence in situ hybridization, an additional cohort of 18 patients was interrogated to supplement WGS findings. The genomic landscape of MaBC uncovered significant genetic alterations that could influence diagnosis and treatment. We found common somatic mutations in key driver genes, such as FAT1, GATA3, SMARCA4, and ARID2. Our study also mapped out structural variants that impact cancer-associated genes, such as ARID1A, ESR1, GATA3, NTRK1, and NF1. Using a WGS-based classifier, homologous recombination deficiency (HRD) was identified in 2 cases, both presenting with deleterious variants in BRCA2. Noteworthy was the observation of FGFR1 amplification in 21% of cases. Altogether, we identified at least 1 potential therapeutic target in 8 of the 10 cases, including high tumor mutational burden, FGFR1 amplification, and HRD. Our study is the first WGS characterization of MaBC, which uncovered potentially relevant variants, including structural events in cancer genes, HRD signatures, and germline pathogenic mutations. Our results demonstrate unique genetic markers and potential treatment targets in MaBC, thereby underlining the necessity of tailoring treatment strategies for this understudied patient population. These WGS-based findings add to the growing knowledge of MaBC genomics and highlight the need to expand research on this type of cancer.

A Rare Case of Remittent Male Invasive Ductal Carcinoma With New Metastasis After Incomplete Adjuvant Therapy

Breast cancer is a rare disease in men with many barriers to effective management such as limited research and treatment modalities. While the current standard of care utilizes mastectomy and axillary dissection with chemotherapy, clinicians must follow the female-staged breast cancer protocol, as there is no established regimen for men. In this case presentation, we report a 43-year-old male with a prior history of ER-positive invasive ductal carcinoma (IDC) who presented with a recurrent breast lesion. The patient had previously undergone left breast mastectomy with sentinel node biopsy with negative margins. The patient declined adjuvant chemotherapy and tamoxifen therapy after the initial dissection. Three years after the primary dissection, the patient presents with a breast lesion and metastasis to bilateral axillary lymph nodes, lungs, and spine. The diagnosis was supported by a right axillary biopsy which revealed an ER-positive and PR-positive lesion. We want to shed light on the importance of complete and thorough treatment of primary IDC in men while highlighting the implications of incomplete treatment. We hope that this clinical case will serve as a guide for physicians in promoting adjuvant treatments after primary tumor removal in male IDC.

Outcomes of Rural Men with Breast Cancer: A Multicenter Population Based Retrospective Cohort Study

Background: Breast cancer is rare in men. This population-based study aimed to determine outcomes of male breast cancer in relation to residence and other variables. Methods: In this retrospective cohort study, men diagnosed with breast cancer in Saskatchewan during 2000–2019 were evaluated. Cox proportional multivariable regression analyses were performed to determine the correlation between survival and clinicopathological and contextual factors. Results: One hundred-eight eligible patients with a median age of 69 years were identified. Of them, 16% had WHO performance status ≥ 2 and 61% were rural residents. The stage at diagnosis was as follows: stage 0, 7%; I, 31%; II, 42%; III, 11%; IV, 8%. Ninety-eight percent had hormone receptor-positive breast cancer. The median disease-free survival of urban patients was 97 (95% CI: 50–143) vs. 64 (46–82) months of rural patients (p = 0.29). The median OS of urban patients was 127 (94–159) vs. 93 (32–153) months for rural patients (p = 0.27). On multivariable analysis, performance status ≥ 2, hazard ratio (HR) 2.82 (1.14–6.94), lack of adjuvant systemic therapy, HR 2.47 (1.03–5.92), and node-positive disease, HR 2.32 (1.22–4.40) were significantly correlated with inferior disease-free survival in early-stage invasive breast cancer. Whereas stage IV disease, HR 7.8 (3.1–19.5), performance status ≥ 2, HR 3.25 (1.57–6.71), and age ≥ 65 years, HR 2.37 (1.13–5.0) were correlated with inferior overall survival in all stages. Conclusions: Although residence was not significantly correlated with outcomes, rural men had numerically inferior survival. Poor performance status, node-positive disease, and lack of adjuvant systemic therapy were correlated with inferior disease-free survival.

A Prospective Population-Based Study of Cardiovascular Disease Mortality following Treatment for Breast Cancer among Men in the United States, 2000-2019

Male breast cancer is rare but its incidence and mortality are increasing in the United States, with racial/ethnic disparities in survival reported. There is limited evidence for cardiotoxicity of cancer treatment among men with breast cancer. We evaluated the relation between breast cancer treatment and cardiovascular disease (CVD) mortality among men and investigated the salient roles that race/ethnicity play on this relation. Data were from 5216 men with breast cancer aged ≥ 40 years from the Surveillance, Epidemiology, and End Results program who were diagnosed from 2000 to 2019 and underwent surgery. Competing risk models were used to estimate hazards ratios (HR) and 95% confidence intervals (CI). During a median follow-up of 5.6 years, 1914 deaths occurred with 25% attributable to CVD. In multivariable-adjusted models, men who received chemotherapy had elevated risk for CVD (HR: 1.55, 95%CI: 1.18-2.04). This risk was higher among Hispanic men (HR: 3.96, 95%CI: 1.31-12.02) than non-Hispanic Black and non-Hispanic White men. There was no significant association between radiotherapy and CVD deaths. In this population-based study, treatment with chemotherapy was associated with elevated risk of CVD mortality in men with breast cancer. Racial/ethnic disparities in the association of chemotherapy and CVD mortality were observed.

Management of Male Breast Cancer: The Journey so Far and Future Directions

Male breast cancer is now shown to be a unique entity and should be considered as a distinct disease. Given the relatively smaller number of cases, randomized controlled trials for treatment are extremely limited and majority of practices are derived from female breast cancer studies. This paper reviews available literature on surgical, radiation, and systemic therapies for male breast cancer, and discusses current practice recommendations.