More trials, better data needed for breast cancer in men

Most treatments extrapolated from breast cancer in women; expert panel said the diseases are not the same.

Breast cancer consortiums in the United States and Europe have pledged to work together to improve clinical trials and access epidemiological data and develop treatment options for men with breast cancer.

Male breast cancer makes up less than 1% of all cancer diagnoses worldwide and almost all data on the disease come from small single-institution studies. To address the dearth of information detailing the optimal treatment for male breast cancer, the NIH Office of Rare Diseases and the National Cancer Institute Divisions of Cancer Epidemiology and Genetics and Cancer Treatment and Diagnosis sponsored a multidisciplinary meeting in September 2008. The Journal of Clinical Oncology recently published an article summarizing the findings from that meeting.

The most important result of the meeting was an agreement to create an international collaboration allowing researchers to share epidemiologic data, clinical information and tumor specimens, said Larissa A. Korde, MD, MPH, assistant professor of medical oncology at the University of Washington and one of the authors of the article.

“With diseases that are very rare, it is difficult for single institutions to generate enough data to make a difference,” she told HemOnc Today. “Collaborations, particularly international collaborations, can be much more successful in answering questions about male breast cancer. We really do need to have international collaboration in order to make some headway in understanding how the biology of male breast is different than female breast cancer.”

Different diseases

Although male breast cancer is similar in some ways to the disease found in women — like women, risk factors for male breast cancer include age, race and exposure to radiation — the authors wrote that “in view of the paucity of data, the rarity of the disease, and different hormonal milieu, male breast cancer should be considered and managed as a distinct entity.”

“The basic biology in men is different than in women, we can’t completely extrapolate everything we’ve learned in women to treat breast cancer in men. The way we do studies in women, we take thousands of patients and enroll them in clinical trials,” Korde said. “In men, less than 2,000 cases diagnosed in the United States per year, it’s very difficult to enroll enough patients on a clinical trial to have confidence that the results we’re seeing are truly statistically significant and clinically meaningful. It’s difficult to make treatment recommendations without that kind of data.”

Korde said the international collaboration between several cooperative group investigators will start by conducting retrospective analyses looking at demographic, clinical and outcome data and collecting tumor blocks from male patients. By pooling data on hundreds of patients, the hope is that researchers can understand the demographics and risk factors associated with the disease. Korde said researchers will also look at tumor blocks to better understand the biology of male breast cancer.

“Once a collaboration like that is formed, it will become a platform on which future studies can be run,” she said. “The idea is that we can propose small clinical trials in male breast cancer focusing on what the key issues involved with treatment are, and find answers we can’t extrapolate from women.”

Korde said there has been some funding allocated in the United States and Europe and there is a protocol already established in Europe that has begun collecting demographic and outcome data and tumor blocks. U.S. institutions are expected to begin contributing to that European database in the near future. The next step, Korde said, would be to prospectively follow patients for outcomes and eventually amass enough patients to conduct a prospective trial. – by Jason Harris

Korde LA. J Clin Oncol. 2010;doi:10.1200.JCO.2009.25.5729.