A population-based study of the impact of post-mastectomy radiation on survival for male breast cancer

Treatment of male breast cancer: meta-analysis of real-world evidence

BACKGROUND

Breast cancer is rare in men and managed by extrapolating from breast cancer in women. The clinicopathological features of male breast cancer, however, differ from those of female breast cancer. Because clinical trials are rare, the synthesis of real-world data is one method of integrating sufficient evidence on the optimal treatment for this patient population.

METHODS

PubMed, Embase, and Cochrane Library databases were searched. Clinical studies were included if they evaluated the treatments of interest in male breast cancer; these evaluations included breast-conserving surgery (BCS) versus mastectomy, postmastectomy radiation therapy versus no radiation, the accuracy of sentinel lymph node biopsy (SLNB), and a comparison of various endocrine therapies.

RESULTS

Forty studies were retrieved. The pooled estimate of overall survival (OS) revealed no difference between BCS and mastectomy groups. Postmastectomy radiation to the chest wall significantly increased OS relative to no postmastectomy radiation (hazard ratio (HR) 0.67, 95 per cent confidence interval 0.54 to 0.84). The pooled estimates of identification and false-negative rates of SLNB were 97.4 and 7.4 per cent respectively. Tamoxifen treatment was associated with significantly increased OS compared with no tamoxifen intake (HR 0.62, 0.41 to 0.95).

CONCLUSION

Identification and false-negative rates for SLNB were comparable to those in female breast cancer. Breast-conserving surgery can be effective and safe; postmastectomy radiation to the chest wall and 5-year tamoxifen treatment improves survival.

Optimizing utilization and indications for adjuvant radiation in male breast cancer

Due to its rarity, there is a dearth of prospective data on optimal therapeutic strategies in male breast cancer (MBC). Treatment recommendations are mostly extrapolated from evidence in female breast cancer (FBC). Data show that MBC has unique clinical and biological characteristics distinct from FBC. Evidence from retrospective studies suggests that effective therapeutic interventions are often underutilized in MBC and this can compromise outcomes. Population based studies contribute significantly towards the understanding of rare cancers. Multiple studies have demonstrated that adjuvant radiation is associated with improved local control and survival in high risk subgroups of MBC. Multi-center consortia studies contribute significantly towards generating prospective data and optimizing diagnostic and therapeutic strategies in these rare cancers. Enhancing the implementation of treatment recommendations and minimizing disparities in access to care will lead to improved outcomes.

Adjuvant Radiation Therapy for Male Breast Cancer-A Rare Indication?

Due to its rarity, there are no randomized trials investigating the outcome of adjuvant radiotherapy in MBC. This study reports on patient and tumor characteristics of 41 consecutive MBC patients treated between 1990 and 2018 and on clinical outcomes after surgical resection of tumors and adjuvant radiotherapy of the chest wall or breast. Local control (LC), locoregional control (LRC), overall survival (OS), disease-free survival (DFS), and toxicity were evaluated. After a median follow-up of 80 months (95% CI: 14.6-213.8 months) there was only one recurrence, in a patient's locoregional lymph nodes 17 months after start of radiotherapy, resulting in an LC rate of 100% at 5 years and a 5-year LRC rate of 97.4% (standard deviation (SD): 0.025). Five-year DFS and OS rates were 64.6% (SD: 0.085) and 57.2% (SD: 0.082), respectively. Adjuvant radiotherapy was tolerated well without high-grade (CTCAE grade > II) adverse events. After tumor resection and adjuvant radiotherapy, LC and LRC rates in MBC patients are excellent and comparable to results found for female breast cancer (FBC) patients. However, as patients are often diagnosed with locally advanced, higher-risk tumors, distant recurrences remain the major failure pattern.

Pattern of care of adjuvant radiotherapy in male breast cancer patients in clinical practice: an observational study

BACKGROUND AND PURPOSE

Due to the rarity of male breast cancer (male BC), no consensus has been reached regarding the most appropriate curative treatment strategy. The objective of the present observational study was to identify patient and tumor characteristics and assess the role of radiotherapy (RT) in clinical practice.

METHODS

Between 1998 and 2014, data of male BC patients treated at two breast centers were consecutively collected and retrospectively analyzed. Patients were stratified based on the addition of adjuvant RT. Data on overall survival (OS) and local recurrence-free survival (LRFS) were estimated with the Kaplan-Meier method and compared by the log-rank test.

RESULTS

A consecutive cohort of 58 male BC patients was evaluated. Median follow-up was 56 months. Twenty-one patients (36.2%) received adjuvant RT. Overall, patients undergoing postoperative RT were characterized by more high-risk features. Patients receiving postoperative RT had significantly more frequently a high UICC stage (50 vs. 9.7% UICC III, p = 0.018) and positive lymph nodes as compared to patients undergoing surgery alone (65 vs. 34.4% pN+, p = 0.046). Accordingly, there was a higher proportion of patients receiving axillary lymph node dissection in the RT group (71.4 vs. 35.6%). Mastectomy was performed in 31/37 (86.1%) in the surgery group as compared to 14/21 (66.7%) in patients receiving postoperative RT. In addition, RT patients were more likely to receive endocrine therapy (78.9 vs. 39.3%, p = 0.016). Outcome was not significantly different between the groups (5-year LRFS: 89.8 vs. 80.0%, p = 0.471 and 5‑year OS 88.4 vs. 88.9%, p = 0.819).

CONCLUSION

The present observational study evaluated the pattern of care in male BC patients treated in clinical practice. Due to its rarity, randomized clinical trials are unlikely and male BC remains an entity with a poor evidence base. Nevertheless, RT remains a crucial component of the multidisciplinary treatment strategy in male BC.