The reasons for the later peak in men remain unclear, the researchers wrote in the study, but possible explanations include nonadherence to endocrine therapy, differences in tumor biologic factors, and differences in the tumor microenvironment between men and women, they noted, in the discussion section.
What Drives the Risk?
Key factors for breast cancer-specific mortality were age, tumor stage, and tumor grade.
The cumulative 20-year risk of BCSM in the current study was 12.4%, 26.2%, and 46.0% for stage I, II, and III, respectively. The adjusted BCSM risk was increased in patients younger than 50 years, those with grade II or III/IV tumors, and those with stage II or III disease.
What Are the Limitations?
The current study by Leone and colleagues was limited by the relatively small subgroup sample of men with stage III and N3 disease, lack of data on the use of systemic therapies, and lack of data on human epidermal growth factor receptor 2 gene (ERBB2), the researchers wrote. However, the long-term follow-up strengthened the results, and the study is the first known to assess 20-year BCSM risk in men with nonmetastatic HR+ breast cancer.
What Do Oncologists Need to Know About the Study?
The study findings indicate that the risk of breast cancer mortality persists for 20 years in men with hormone receptor–positive breast cancer, Dr. J.P. Leone said in an interview. As in women, the risk depends on traditional clinicopathologic factors, he noted.
“However, the kinetics of that risk appears to be different between men and women. In order to reduce the breast cancer mortality risk in men with hormone receptor–positive breast cancer, it will be important for men to consider the benefits of the treatment options that may be indicated for their specific situation,” he said.
“I think early detection is also very important,” he emphasized. To that end, increased awareness of the possibility for breast cancer in men, as well as prompt intervention when breast cancer is suspected, will help to improve early detection when the risk of breast cancer mortality is lower, he added.
What Are the Next Steps for Research?
“I think our study underscores the need for additional research to improve our adjuvant therapy options in both men and women with hormone receptor-positive breast cancer, to reduce the risk of long-term mortality,” he said.
The study received no outside funding. Lead author Julieta Leone had no financial conflicts to disclose. Dr. José P. Leone disclosed receiving institutional grants from Kazia Therapeutics and Seagen unrelated to the current study.