The largest study to date of male breast cancer finds, contrary to previous reports, breast cancer rates in men are increasing though the disease remains rare. A new study published May 24, 2004 in the online edition of CANCER, a peer-reviewed journal of the American Cancer Society, concludes there are significant differences in the presentation of breast cancer between the sexes though survival rates remain similar. The full study will be available via Wiley InterScience
, and will appear in the July 1, 2004 print issue.
Male breast cancer is a rare malignancy, representing only 0.6 percent of all breast cancers and less than 1 percent of cancers in men. Because it is so rare and poorly studied, there is limited data regarding its epidemiology, treatment, and prognosis. Moreover, studies to date conflict on whether the disease presents the same in men as it does in women. To fill in the gaps in clinical knowledge of male breast cancer, researchers analyzed data collected from 1973 to 1998 and included in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database representing the largest study to date of male breast cancer.
Researchers led by Dr. Sharon H. Giordano of the University of Texas M. D. Anderson Cancer Center found that the incidence of breast cancer in men increased significantly, from 0.86 to 1.08 cases per 100,000 men over 25 years. Still, this increase was not as dramatic as the increase in female breast cancer over the same period. For both genders risk increased with age, and stage-for-stage there was no difference in survival.
The study also found men tend to be diagnosed at an older age (67 years) than women (62 years). Clinically, men are more likely to present with disease in axillary lymph nodes, at a more advanced stage of disease, and with estrogen and progesterone receptor positive tumors. The two most common types of breast cancer in men were invasive ductal or unclassified carcinomas (93.4 percent) and papillary carcinomas (2.6 percent).
Larger tumor size and axillary lymph node disease were independently associated with shortened survival. Tumor grade and receptor status were not.
The authors conclude: "this data suggests that the incidence of male breast cancer is climbing, men are diagnosed with later stage disease than women, and that hormone receptor status and tumor grade are not independent prognostic factors for men."