Treatments for male breast cancer patients are not well-understood. A study found that men with progesterone receptor (PR)-negative, nonmetastatic breast cancer and PR-positive, stage II and stage III breast cancer may benefit from chemotherapy.
Fewer than 1% of all breast cancer cases occur in males, according to the researchers, so treatment strategies are often derived from data on female patients. Most male breast cancer patients receive modified radical mastectomy; chemotherapy and radiotherapy regimens for males are often similar to those for females, and males with hormone receptor–positive breast cancer are recommended for tamoxifen.
“However, not all of the adjuvant treatment strategies are suitable for men with breast cancer. Male breast cancer also requires individualized treatment,” the study authors explained.
One barrier to data is the small number of clinical trials, which are often terminated “due to a lack of recruitment,” the study authors noted. “Therefore, to our knowledge, there are few data regarding the administration of chemotherapy in men with breast cancer.”
To garner a better understanding of treating this patient population specifically, the researchers queried the Surveillance, Epidemiology, and End Results cancer database from 1990 to 2014 for data on males with invasive stage I to III breast cancer.
Final analysis included 2,713 male breast cancer patients. The median age (range) was 67 (10-104) years; most patients (55.4%) were aged between 60 and 80 years. More than half of patients (n=1,455; 53.3%) were diagnosed with T1 disease, and an even greater proportion (n=1,622; 59.4%) had N0 disease. There were 103 ER negative tumors (3.8%) and 315 PR negative tumors (11.5%). Mastectomy was performed in 89.4% of patients, and 74.3% did not receive chemotherapy.
About two-thirds of patients (66.9%) did not undergo chemotherapy. Factors associated with receiving chemotherapy included age, T classification, N classification, tumor grade, and PR status. Chemotherapy significantly reduced all-cause mortality (26% reduction; P<0.001) and breast cancer–specific mortality (21% reduction; P=0.085). Among PR-negative male breast cancer patients, chemotherapy use improved breast cancer–specific survival (hazard ratio [HR], 0.50; 95% confidence interval [CI[, 0.28 to 0.91; P=0.023) and overall survival (HR, 0.54; 95% CI, 0.37 to 0.77; P=0.001), but chemotherapy was not correlated with breast cancer–specific survival for all men with PR-positive tumors (P=0.959). Chemotherapy improved overall survival among men with PR-positive stage II and stage III breast cancer (HR, 0.78; 95% CI, 0.66 to 0.92; P=0.004).
The study was published in Cancer.
“Chemotherapy should be considered for patients with PR‐negative, nonmetastatic male breast cancer. In addition, chemotherapy also should be considered for men with PR‐positive, stage II and stage III breast cancer. Future prospective studies still are needed to confirm the current study results due to known and unknown biases,” the study authors concluded.