The 21-Gene Recurrence Score in Male Breast Cancer

Male Breast Cancer: Three Case Reports and a Literature Review

INTRODUCTION

Male breast cancer (MBC) accounts for 0.5%-1% of all breast cancers diagnosed worldwide. However, its biological characteristics can be distinguished from that of female breast cancer (FBC).

CASE REPRESENTATION

The diagnostic and treatment approaches for MBC are mainly similar to that of FBC due to the lack of male breast cancer-related studies, clinical trials, and literature. An increasing number of retrospective and prospective studies have been conducted to clarify the individualized care for MBC. Herein, we report three cases of advanced MBC to describe the diagnostic approaches, treatment process, and survival prognosis.

CONCLUSION

MBC patients had older age, later stage at first diagnosis, higher expression of hormone receptors, and poor prognosis. A literature review was conducted to determine the incidence, risk factors, disease features, diagnosis, treatment, survival, and management of MBC.

Prognostic difficulties of men with breast cancer

Most adequately powered studies confirm a worse prognosis for males versus matched females with breast cancer. There is in-stage migration for stage I cancers with a different ratio of tumor/normal breast tissue in males. Younger men have a better prognosis, largely the result of increased morbidity in the elderly, exacerbated by smoking, low socioeconomic differences, and ethnic disparity. BRCA2 carriers with MBC have a worse outcome than noncarriers as do men with amplification of EMSY. Men with tumors having a high cytosol level of plasminogen activator inhibitor 1 (PAI-1) may have more invasive cancers leading to earlier spread and hence a worse outcome. PREDICT+ is a useful prognostic model for MBC and multigene testing enables more specific systemic therapies to be used.

Male Breast Cancer: 13-Year Single Institution Experience

Due to the low incidence of male breast cancer (BC), there are few studies evaluating outcomes. We evaluated the clinicopathologic features and outcomes of male BC. Male patients with BC from January 2006 to December 2018 were identified. Of 49 patients, mean age was 64 (range 33-94) years. Of the 27 (55.1%) patients who had genetic testing, 9 (33.3%) had a Breast Cancer gene (BRCA) 1 or 2 mutation. The majority of patients had a mastectomy (n = 43/49, 87.8%) and had invasive ductal carcinoma (n = 47/49, 95.9%). 20 patients (n = 20/43, 46.5%) had positive lymph nodes. 41 (n = 41/47, 87.2%) patients had estrogen receptor positive disease. The majority of patients were pathologic stage 2 (n = 21/46, 45.7%), followed by stage 1 (n = 15/46, 32.6%), stage 3 (n = 6/46, 13.0%), and stage 4 (n = 4/46, 8.7%). Eight patients had the 21-gene recurrence score performed. Of patients with stage 1-3 BC, 10 (n = 10/43, 23.3%) patients had recurrence. With median follow-up of 4.1 (range .6-10.6) years, 5-year overall survival was 82.9% and 5-year disease-free survival was 65.9%. In conclusion, our cohort of patients with male BC had a high incidence of BRCA mutations and most commonly had high-grade estrogen positive stage 2 tumors. Breast conserving surgery was utilized in 4% of patients and genomic testing utilized in 55% of patients.

Pharmacological management of male breast cancer

INTRODUCTION

Despite its rarity, male breast cancer shows a steadily rising incidence. Given the absence of ad hoc prospective randomized clinical trials, treatment strategies are based on extrapolation from female breast cancer recommendations or solely on population-based data.

AREAS COVERED

This review discusses the current treatment landscape for male breast cancer in the adjuvant and in the metastatic setting. The authors also discuss the biology and genomic landscape of male breast cancer. Original research and review articles, relative to the period 2010-2019, were included in the review of the literature.

EXPERT OPINION

There is a major medical need to include male patients with breast cancer in prospective clinical trials. The call to equality in breast cancer care can be pursued via two divergent paths: (i) a gender-neutral delivery of breast cancer information and (ii) the creation of separate sections, for the more common female breast cancer and for the rare male ones. We propose to differentiate male breast cancer care, acknowledging unique onco-sexual and social needs that can be only partially shared.

Multigene testing in breast cancer: What have we learned from the 21-gene recurrence score assay?

Most invasive breast cancers express hormone receptors (HR) and typically have a favorable prognosis following endocrine therapy. Patients at a higher risk of recurrence can be identified by multigene prognostic classifiers such as the 21-gene recurrence score (RS) assay, 70-gene prognostic signature, PAM-50, 12-gene molecular score, and others. The 21-gene RS assay (Oncotype Dx™, Genomic Health, Redwood City, CA) has level I clinical evidence and is the most widely used multigene assay in North America. The RS assay is based on reverse transcriptase polymerase chain reaction that can be performed on the RNA isolated from formalin-fixed paraffin-embedded tissue. It evaluates the expression of 16 cancer-related genes developed based on a multi-step approach. Due to its ability to assess recurrence risk and predict potential benefit from chemotherapy, the assay is recommended for patients with node-negative, HR-positive, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer by the American Society of Clinical Oncology, National Comprehensive Cancer Network clinical practice guidelines in oncology, European Society for Medical Oncology clinical practice guidelines, and St. Gallen consensus panel guidelines. The RS assay has also been incorporated in the prognostic stage groups in the 8th edition of the American Joint Commission of Cancer staging manual in order to provide essential genomic information for optimal treatment decisions. This review will focus on the utility of the RS assay in HR-positive and HER2-negative breast cancer patients, including risk of distant and locoregional recurrence in node-negative and node-positive tumors, association with radiotherapy, special subtypes of breast cancer, practical issues related to selecting tumors for testing, and overview of the recently published TailorX (Trial Assigning IndividuaLized Options for treatment [Rx]) results.

Features, Outcomes, and Management Strategies of Male Breast Cancer: A Single Institution Comparison to Well-Matched Female Controls

Objective

The primary objective of this study was to delineate differences in management, overall and distant disease-free survival in males diagnosed with breast cancer and treated at The Ohio State University Comprehensive Cancer Center as compared to comprehensively matched female subjects. Secondary objectives included assessment of clinical and histopathologic features and recurrence score, as measured by Oncotype DX and the modified Magee equation #2.

Materials and Methods

This single institution retrospective study compared male and comprehensively matched female patients (1:2) with stage I-III breast cancer between 1994 and 2014. Recurrence risk was estimated using a modified Magee equation. Overall survival and distant disease-free survival were estimated and compared using Kaplan-Meier and Log-rank methods.

Results

Forty-five male breast cancer patients were included (stage I: 26.7%; stage II: 53.3%; stage III: 20.0%; hormone receptor positive: 97.8%; human epidermal growth factor receptor 2 negative: 84.4%) with a median age of 63.8 (43.0-79.4) years at diagnosis. Intermediate and low recurrence scores were most common in male and female patients respectively; mean score was similar between groups (20.3 vs. 19.8). The proportion of male breast cancer patients treated with adjuvant chemotherapy and post-mastectomy radiation was lower compared to female patients (42.2% vs. 65.3%, p=0.013; 22.7% vs. 44.4%, p=0.030, respectively). Overall survival and distant disease-free survival between male and female patients were similar.

Conclusion

Male breast cancer patient outcomes were similar compared to well-matched female patients suggesting that breast cancer specific factors are more prognostic than gender.

Sex Disparity Observed for Oncotype DX Breast Recurrence Score in Predicting Mortality Among Patients with Early Stage ER-Positive Breast Cancer

PURPOSE

Prognostic value of Oncotype DX Breast Recurrence Score (RS) in male patients with breast cancer is understudied. We evaluated associations of RS with overall mortality in male patients with breast cancer and compared it with female counterparts.

EXPERIMENTAL DESIGN

With a cohort of 848 male and 110,898 female patients with breast cancer identified from the National Cancer Database (2010-2014), we estimated HRs and 95% confidence intervals (CI) for overall mortality associated with RS using Cox regression models. RS was evaluated continuously, as well as by categorization following respective traditional (≤17, 18-30, and ≥31) and TAILORx (≤10, 11-25, and ≥26) cutoffs.

RESULTS

RS was positively associated with mortality in male patients (HR = 1.13; 95% CI, 1.02-1.26 per unit RS increment) up to RS > 21, after which the risk plateaued. Among female patients, mortality began to increase with RS only when RS > 23 (HR = 1.02; 95% CI, 1.01-1.02 per unit of RS increment). The intermediate- (HR = 5.37; 95% CI, 1.79-16.11) and high-risk diseases (HR = 4.28; 95% CI, 1.22-14.97) defined by TAILORx, but not traditional cutoffs established for female patients, were associated with elevated mortality risk in men even after adjustment for demographic, clinical characteristics, and treatments, except chemotherapy.

CONCLUSIONS

RS is associated with mortality in male patients with breast cancer at a much lower threshold than that for female patients. Studies are needed to establish specific guidelines for RS thresholds for male patients with breast cancer.

Characterization and prognosis of estrogen receptor-positive/progesterone receptor-negative male breast cancer: a population-based study

Background

The aim of this study was to explore the characteristics and prognostic information of estrogen receptor-positive/progesterone receptor-negative (ER+/PR−) male breast cancer.

Methods

Using the US National Cancer Institute’s Surveillance, Epidemiology, and End Results database, we compared the demographics, clinical characteristics, and outcome of estrogen receptor-positive/progesterone receptor-positive (ER+/PR+) patients with ER+/PR− male breast cancer patients from 1990 to 2010. Two thousand three hundred twenty-two patients with ER+/PR+ tumors and 355 patients with ER+/PR− tumors were included in our study.

Results

ER+/PR− patients were younger (P = 0.008) and more likely to be African American (P < 0.001) while presented with higher histological grade (P < 0.001), larger tumor size (P = 0.010), and more invasion to the lymph nodes (P = 0.034) and distant sites (P < 0.001), thus later stage (P = 0.001). Despite higher chance of receiving chemotherapy (51.0% vs 36.5%, P < 0.001), ER+/PR− patients experienced significantly worse breast cancer-specific survival (BSCC) (P < 0.001) and shorter overall survival (OS) (P = 0.003). Multivariate Cox model confirmed that tumor size, lymph node invasion, metastasis, and surgery were independent prognostic factors of both BSCC and OS for ER+/PR− male breast cancer. Age at diagnosis and chemotherapy were significantly associated with OS but not with BSCC.

Conclusion

ER+/PR− male breast cancer was more aggressive and experienced shorter survival than ER+/PR+ patients. The prognosis was mainly associated with tumor size, lymph node invasion, metastasis, and surgery.

Characterising the adipose-inflammatory microenvironment in male breast cancer

Male breast cancer (MBC) incidence seems to parallel global increases in obesity. The stromal microenvironment contributes to carcinogenesis; yet, the role of adipocytes in this is understudied in MBC. We identified four cohorts of male breast tissues diagnosed when obesity was rare (archival cohort) and more common (contemporary cohort). We examined the microenvironment of archival and contemporary cohorts of MBC, diagnosed 1940-1970 and 1998-2006, respectively, with two cohorts of, archival and contemporary gynaecomastia, diagnosed 1940-1979 and 1996-2011, respectively, serving as controls. We quantified adipocytes, crown-like structures (CLS) and the presence of CD8, α smooth muscle actin (αSMA) and CD68+ macrophages in both cohorts, and determined how these affected survival, in the contemporary MBC cohort. In both MBC cohorts, mean adipocyte diameter was larger in the distant stroma compared with stroma close to the invading tumour (92.2 µm vs 66.7 µm). This was not seen in gynaecomastia. CLS were more frequent in both MBC cohorts than gynaecomastia (44/55 (80%) vs 11/18 (61%), P < 0.001). No relationship was found between CLS number and adipocyte size, although there were greater numbers of CLS in contemporary MBC > archival MBC > gynaecomastia. CD8 and CD68 expression in the stroma was significantly associated with reduced survival, with no effects seen with αSMA. Changes in the adipose-inflammatory microenvironment may be a contributing factor to the increase seen in MBC diagnosis.