Risk Stratification and Treatment Options Differ for Male and Female Patients With Breast Cancer

Optimal risk stratification differs between male and female breast cancers. Outcomes for male patients with breast cancer were not significantly correlated with histologic grade, unlike for female patients. Overall survival was associated with mitotic activity index in male breast cancer patients, according to research presented at the 10th European Breast Cancer Conference.¹

Male breast cancer accounts for only 1% of breast cancer cases. So, men and even physicians have little awareness of the disease, which results in late diagnoses that affect prognosis.

This study examined 1203 tumor samples from male patients with breast cancer. These samples came from the largest series of this disease ever linked to outcome data, as the data included 1483 patients from 23 centers in 9 countries. This research examined some differences between male and female breast cancers, which may help in making better treatment choices for male patients with breast cancer.

“Besides conventional tumor tissue characteristics, such as subtype and grade, we also examined additional features, such as the development of fibrotic connective tissue, and the density of tumor infiltrating lymphocytes, a type of white blood cell often found in tumors and implicated in killing tumor cells,” said Carolien van Deurzen, MD, a pathologist specializing in breast cancer at the Erasmus Medical Centre, Rotterdam, The Netherlands, and senior author of the study. “Interestingly, we found that these 2 last factors were strongly associated with outcomes in male breast cancer, whereas tumor grade, a commonly used prognostic measure in female breast cancer, was not.”

The researchers suggested that the lack of association between grading and outcome in men might be due to the different distribution of breast cancer subtypes in male patients. A large portion of male breast cancers were found to be luminal, or estrogen-receptor positive, while HER2-positive and triple-negative subtypes are more common in women.

“However, this subtyping of breast tumors does not seem to result in an optimal risk classification for male breast cancer patients. Additional tests that are well established in women, including gene-expression profiling, may result in the identification of more accurate prognostic and predictive markers. These could enable us to take better treatment choices, individualized for each patient, particularly in regard to the use of chemotherapy and new targeted agents,” said van Deurzen.

The researchers hope to begin a clinical trial soon using a new agent that blocks the androgen receptor, a protein frequently present in male breast cancer, for the patients in the program.

“These are important conclusions from this international project. It has always been assumed, based on limited information, that men with breast cancer should be treated in the same way as women; for the first time, by studying over 1000 cases, it is becoming clear that that this is not so,” said David Cameron, MD, professor of Oncology at the University of Edinburgh in the United Kingdom.

REFERENCE

1. Vermeulen MA, Slaets L, Cardoso F, et al. Pathologic prognostic factors of male breast cancer: results of the EORTC 10085/TBCRC/BIG/NABG International Male Breast Cancer Program. Oral presentation at: 10th European Breast Cancer Conference; March 9-11, 2016; Amsterdam, The Netherlands. Abstract 7.