Obesity, High BMI, and Hormonal Disorders Are Among the Risk Factors for Male Breast Cancer, Researchers at NCI and CPIC Confirm

Fremont, California (EastBayDaily) — While male breast cancer is uncommon, men who are obese, or who have never had children, are at increased risk of developing this disease, according to researchers at the National Cancer Institute (NCI), the Cancer Prevention Institute of California (CPIC), and their colleagues.

In addition, this new study confirms that men with the chromosomal disorder Klinefelter syndrome are at very high risk of male breast cancer; and men who have gynecomastia, a hormonal condition associated with excess estrogen, are also at greater risk of developing breast cancer. The researchers found slightly elevated risk for men who have a history of diabetes, as well.

“By pooling data from 21 participating studies worldwide, we created a unique opportunity to assess risk factors for male breast cancer among a very large group of patients and controls,” said Ann Hsing, Ph.D., chief scientific officer at CPIC. “We confirmed that male breast cancer is associated with a number of hormonal factors, as well as factors related to weight, height and body mass index, or BMI.”

The causes of male breast cancer are not well understood and have not been widely studied. These new findings are of particular importance due to the large number of patients and non-patients, or controls. Data for more than 54,000 participants were evaluated as part of the Male Breast Cancer Pooling Project.

While the researchers noted a consistent relation between obesity and male breast cancer, this link was independent of the risk associated with Klinefelter syndrome or gynecomastia. The association for obesity observed in men was of interest given a similar pattern for female postmenopausal breast cancer. In fact, the approximate 30 percent increased risk the researchers noted in men is nearly identical to that for postmenopausal women.

“Many of these risk factors support the need for exploring the role of specific hormones in male breast cancer,” said Dr. Hsing. “We plan to conduct future analyses using samples from participants in this current study.”

The study, titled “Anthropometric and Hormonal Risk Factors for Male Breast Cancer: Male Breast Cancer Pooling Project Results,” was published in the March issue of the Journal of the National Cancer Institute.

About the Cancer Prevention Institute of California The Cancer Prevention Institute of California (CPIC) is the nation’s premier organization dedicated to preventing cancer and to reducing its burden where it cannot yet be prevented. CPIC tracks patterns of cancer throughout the entire population and identifies those at risk for developing cancer. Its research scientists are leaders in investigating the causes of cancer in large populations to advance the development of prevention-focused interventions. CPIC’s innovative cancer prevention research and education programs, together with the work of the Stanford Cancer Institute, deliver a comprehensive arsenal for defeating cancer. For more information, visit CPIC’s official website at http://www.cpic.org.


Jana Cuiper