Research Yields New Insights Into Male Breast Cancer and Its Treatment

Photo Courtesy © SABCS/Scott Morgan 2014

Fatima Cardoso, MD

New research has found that the overall survival of male patients with breast cancer has improved over time, but the improvement is not as good as it has been for female patients with breast cancer, according to research presented at the 2014 San Antonio Breast Cancer Symposium.

The research, which is part of the largest series of male breast cancer cases ever studied, set out to get a better understanding of this rare form of cancer in men.

“Although we saw a significant improvement in overall survival for male breast cancer patients over time, the prognosis for men with breast cancer has not been improving as much as for women with the disease,” Fatima Cardoso, MD, director of the breast unit at the Champalimaud Cancer Center in Lisbon, Portugal, said in a statement. “This is largely because male breast cancer is a rare disease—it accounts for just 1% of breast cancers—and we know very little about its biology and how best to treat patients.”

For the study, Cardoso and her colleagues examined data from 1473 men with breast cancer who were treated between 1990 and 2010 at 23 centers in 9 countries.

The analysis also showed that men diagnosed with breast cancer were not well managed, Cardosa said.

“For example, even though most male breast cancers are ER-positive, we found that only 77% of patients received endocrine therapy like tamoxifen,” she said. “We also found that even though 56% of male breast cancers are diagnosed when the tumors are very small, only 4% of patients had breast-conserving surgery; most had a mastectomy, which significantly impacted their quality of life.”

Tumor analyses of the male breast cancer patients showed that 92% were positive for the estrogen receptor (ER), 5% were positive for HER2, and 1% were triple-negative. In women, approximately 70% of breast cancers are ER-positive, 20% are HER2-positive, and 10% to15% are triple-negative.

“Our results provide new insight into the clinical and biological characteristics of breast cancer in men, and show that they are not the same as those previously reported for breast cancer in women,” Cardoso said.

The tumor samples were analyzed in central locations using the same protocols so that variation in analyses could be minimized. This will also help Cardoso and her colleagues continue onto parts two and three of the project.

“We are continuing to analyze the tumor samples that we collected during this first part of the project,” Cardoso said. “But we have also begun part two, which is the prospective register of all men diagnosed with breast cancer in many European, Latin American, and North American countries during a 2-year period. This will allow the collection of a current series of these patients and assert the ability of the network to run clinical trials in this rare disease. We also hope to soon begin part three of the project, which will be a clinical trial to test a potential new treatment option for men with breast cancer.”