Overall survival (OS) for male breast cancer patients was worse for black men, men with multiple comorbidities, and men undergoing total mastectomy, according to the results of an analysis of cases from the National Cancer Data Base. The findings of the retrospective study of men with stage I through stage III breast cancer were published in the journal Cancer.
The study “highlights unique practice patterns and factors associated with prognosis,” senior study author Kathyrn J. Ruddy, MD, MPH, of the Mayo Clinic in Rochester, Minnesota, said in a press release. “The racial, economic and age-related health disparities we found could inform future efforts to target interventions to optimize outcomes in men with breast cancer.”
Male breast cancer is rare, accounting for an estimated 1% of newly diagnosed breast cancer cases. There has been scant research of optimal treatment options or prognosis. In August 2019, the US Food and Drug Administration (FDA), recognizing the need for more research, issued a draft of a guidance for the inclusion of men in breast cancer clinical trials.
In order to assess the treatment of male breast cancer patients and what factors affect their outcomes, the Mayo Clinic research team analyzed National Cancer Data Base data for 10,873 patients. The median patient age was 64 years. A quarter of patients underwent breast tissue-conserving surgery and 70% of those patients also underwent radiotherapy. The analysis also showed 44% of patients underwent chemotherapy. Sixty-two percent of patients with estrogen receptor-positive tumors underwent anti-estrogen treatment.
“Oncotype DX was ordered in 35% of patients with lymph node-negative, estrogen receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors,” the authors reported. “During the study period, there was a significant increase in the rates of total mastectomy, contralateral prophylactic mastectomy, radiotherapy after breast conservation, ordering of Oncotype DX, and the use of endocrine therapy (Ps < .05).”
Multivariate analyses revealed that older age at diagnosis, black race, higher comorbidity, higher tumor grade and stage, and total mastectomy were all associated with poorer OS. Postmastectomy radiotherapy was associated with improved OS in a subset analysis of patients with lymph node-positive disease, but that association fell to statistical nonsignificance in a multivariate analysis controlling for age, race, insurance status, income, education, urban/rural residence, comorbidity, tumor histology, grade and stage, and ER/PR status.
“Residing in a higher income area; having progesterone receptor-positive tumors; and receipt of chemotherapy, radiotherapy, and endocrine therapy were associated with better overall survival,” the authors reported. “Despite the lack of prospective randomized trials in patients with male breast cancer, the results of the current study demonstrated that the treatment of this disease has evolved over the years.”
The findings bolster previous research, commented Cynthia Ma, MD, PhD, a breast oncologist and Professor of Medicine at the Washington University School of Medicine in St. Louis, Missouri.
“Breast cancers in males often are diagnosed at an older age, which is often associated with increased incidence of comorbidities,” noted Ma, who was not involved in the study. “Additionally, male breast cancer is often diagnosed at a higher stage since a majority present with a palpable lesion, rather than being screen detected.”