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

A nomogram for predicting the risk of male breast cancer for overall survival

Background

Male breast cancer (MBC) is a rare disease, accounting for <1% of all male carcinomas. Lack of prospective data, the current therapy for MBC is based on retrospective analysis or information that is extrapolated from studies of female patients. We constructed a nomogram model for predicting the overall survival (OS) of MBC patients and verify its feasibility using data from China.

Methods

Constructed a predictive model using 1224 MBC patients from the Surveillance, Epidemiology and End Results (SEER) registry between 2010 and 2015. The performance of the model was externally validated between 2002 to 2021 using 44 MBC patients from the Fujian Medical University Union Hospital. The independent prognostic factors were selected by univariate and multivariate Cox regression analyses. The nomogram was constructed to predict individual survival outcomes for MBC patients. The discriminative power, calibration, and clinical effectiveness of the nomogram were evaluated by the receiver operating characteristic (ROC) curve, and the decision curve analysis (DCA).

Results

A total of 1224 male breast cancer patients were in the training cohort and 44 in the validation cohort. T status (p<0.001), age at diagnosis (p<0.001), histologic grade (p=0.008), M status (p<0.001), ER status (p=0.001), Her2 status (p=0.019), chemotherapy (p=0.015) were independently associated with OS. The diagnostic performance of this model was evaluated and validated using ROC curves on the training and validation datasets. In the training cohort, the nomogram-predicted AUC value was 0.786 for 3-year OS and 0.767 for 5-year OS. In the validation cohort, the nomogram-predicted AUC value was 0.893 for 3-year OS and 0.895 for 5-year OS. Decision curve analysis demonstrated that the nomogram was more benefit than the AJCC stage.

Conclusions

We developed a nomogram that predicts 3-year and 5-year survival in MBC patients. Validation using bootstrap sampling revealed optimal discrimination and calibration, suggesting that the nomogram may have clinical utility. The results remain reproducible in the validation cohort which included Chinese data. The model was superior to the AJCC stage system as shown in the decision curve analysis (DCA).

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.

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.

The use of adjuvant radiation therapy in male breast cancer and its impact on outcomes

BACKGROUND

Male breast cancer (MBC) accounts for 1% of all breast cancers and there is a paucity of data on factors impacting the treatment strategies and outcomes. We sought to use a large national database to examine trends and predictors of the use of adjuvant radiation (Adj-RT), as well as any association with outcome.

METHODS

We queried the National Cancer Database (NCDB) for patients with stages I-III MBC treated with surgery (breast conservation surgery-BCS or mastectomy-MS) within 180 days of diagnosis (years 2004-2015). Multivariable logistic regression identified predictors of adj-RT receipt. Multivariable Cox regression evaluated predictors of survival. Propensity matching for adj-RT was used to account for indication biases.

RESULTS

We identified 6,217 patients meeting the eligibility criteria (1457 BCS vs. 4760 MS). The majority of patients were Caucasian (85%) and in an age range of 50-80 years (74%). Although adj-RT was omitted for 30% of BCS patients, the utilization was higher compared to MS (OR=26, p-value=0.001). The predictors of adj-RT use included African-American race, more advanced stage, higher grade, presence of lymphovascular invasion, and ER/Her-2 positivity for the entire cohort and increased age, urban location and higher income for BCS. Adj-RT was associated with lower mortality in the propensity matched model (overall HR for BCS=0.28, p-value<0.001; overall HR for MS=0.62, p-value=0.001).

CONCLUSION

This study demonstrates that while adj-RT after BCS is associated with decreased mortality in MBC patients, adj-RT is omitted in up to a third of cases of MBC after BCS despite being standard of care.

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.

Low-Grade Adenosquamous Carcinoma of the Axilla of Breast Origin in a Male: A Case Report and Literature Review

Low-grade adenosquamous carcinoma (LGASC) is a rare invasive tumor that occurs in breast parenchyma. It has previously only been reported in females. Herein, we describe the case of a 52-year-old male who presented with a palpable mass in his right axilla that he reported had been present for 20-years. This is the first report of a male patient with LGASC. Core needle biopsy pathology revealed a benign mass of mammary origin, but its type was initially misdiagnosed. It was only correctly identified via postoperative pathology after local excision, which indicated that the mass exhibited the typical pathological characteristics of LGASC. Immunohistochemical analysis revealed positive expression of estrogen receptor, which was inconsistent with the typical “triple-negative” immunophenotype of LGASC. After resection of the mass the patient was advised to participate in regular outpatient follow-up. In conclusion, LGASC should be considered in male patients with a mass lesion in their breast or axilla, even when core needle biopsy indicates a benign mass of breast origin. One-stage local resection is recommended for the treatment of male patients with LGASC, but it is crucial to ensure that the margins are negative and postoperative adjuvant radiotherapy is not recommended.

Epidemiology of male breast cancer

Background

Due to its rarity, few studies have characterized the epidemiology of male breast cancer. The purpose of this study was to determine survival and risk factors for male breast cancer in a large U.S. population.

Methods

In this study, 19,795 male patients with breast cancer were identified from the National Cancer Database (2004–2014). Patient demographics, tumor characteristics and treatments were analyzed by using descriptive statistics. We used multivariate Cox regression and Kaplan Meier analysis.

Results

Over 10 years, the incidence of male breast cancer increased from 7.2% to 10.3%, while mortality decreased from 11% to 3.8%. Socioeconomic factors predicting mortality included income medium, and high vs low (HR = 0.78; 0.68), private vs no insurance (HR = 0.73) and the academic research facility vs community cancer center (HR = 0.79). Significant predictors of all-cause mortality included age (HR = 1.04), tumor size (HR = 1.01), hormone receptor expression (HR = 0.8) and cancer stage I vs II, III, and IV at the time of diagnosis (HR = 1.5, 2.7, 4.4, 9.9 respectively). Other predictors of mortality include surgery (HR = 0.4), chemotherapy (HR = 0.8), radiation (HR = 0.8), and hormonal therapy (HR-0.8).

Conclusions

Socioeconomic factors, cancer stage, tumor characteristics (size and grade), and high Charlson-Dayo score contributed to higher mortality among male patients diagnosed with breast cancer. Surgery was most effective, followed by radiation, chemotherapy, and hormonal therapy. Patients with positive ER or PR expression demonstrated better survival. Adjusting for socioeconomic factors, biomarker identification and timely, appropriately chosen treatment are likely to reduce the risk for mortality.

1

Mortality was higher among patients with Low income and with no insurance.

2

Patients with positive ER or PR expression demonstrated better survival.

3

Surgery, chemotherapy, radiation, and hormonal therapy improved survival.