Largest ever study of male breast cancer treatment shows more mastectomy, less radiation than in female disease

University of Colorado Cancer Center researchers used data from 4,276 cases of male breast cancer and 718,587 cases of female breast cancer to show that the disease is treated differently in men than in women. Specifically, male breast cancer is treated with mastectomy more often than female breast cancer, and in cases in which locally advanced female breast cancer is commonly treated with radiation, the treatment is less used in the male disease.

"We know very little about male breast cancer since it comprises only 0.6 percent of all breast cancer, and nearly all therapy is based on female breast cancer studies. This study demonstrates that just as in women, men with early stage breast cancer have the same outcome with a mastectomy or a lumpectomy followed by radiation. In women, breast-conserving surgery is the standard and preferred treatment for the majority of women. Still, 87 percent of men in this study, compared to only 38 percent of women during the same time period, underwent mastectomy for early stage disease," says Rachel Rabinovitch, MD, investigator at the CU Cancer Center and professor of Radiation Oncology at the University of Colorado School of Medicine.

"Traditionally, breast conservation is not even considered for men with breast cancer. But in a world in which a man's appearance is increasingly important, and where it is common for men to be seen without a shirt in the gym or on the beach, mastectomy can have overlooked psycho-sexual impacts on men, just as in women," Rabinovitch says.

The group's data comes from the US Surveillance, Epidemiology and End Results (SEER) Program database, which has collected cancer statistics since 1973 and includes tumor type, demographics, treatment and outcome information for about 28 percent of the U.S. population.

"Because male breast cancer is a rare disease, it isn't studied prospectively – it is very challenging to enroll enough patients in a trial evaluating therapy for male breast cancer. To learn about the disease from large patient groups, we have to look back through collected data, like that in SEER. So the question becomes what can you learn from these numbers? What can you find that's useful, practical, new and interesting?" Rabinovitch says.

The study also shows that whereas mastectomy may be over-used in male breast cancer, radiation therapy may be under-utilized. In locally advanced breast cancer the disease is comprised of a large tumor mass or has spread to the surrounding chest wall, nearby skin or underarm lymph nodes but not yet to other organs. In the current study, 34 percent of males with locally advanced disease were treated with radiation therapy following mastectomy, compared with 45 percent of females with similar disease.

"I think these findings point to new areas of research and should push clinicians to consider the advantages of breast conserving therapy with their patients. It's a new conversation – surgeons and oncologists shouldn't assume that men are fine with a mastectomy," Rabinovitch says.