Incidence of prostate cancer in male breast cancer patients: a risk factor for prostate cancer screening.

Synchronous or metachronous occurrences of both prostate cancer and male breast cancer are rarely reported, but provide insight into their hormonal and genetic biology. We sought to determine the incidence of prostate cancer in male breast cancer patients at our institution, and to examine estrogen receptor (ER), progesterone receptor (PR) and HER-2/neu receptor (HR) status in these patients. A retrospective review was conducted of male breast cancer patients from 1990 to 2006. Histopathologic characteristics and hormone receptor expression was obtained. In 69 patients with male breast cancer, 12 (17%) also had a diagnosis of prostate cancer. Nine had ER-positive status and three were unreported. PR status was positive in 5, whereas 3 had PR-negative status. HR status was positive in 1, whereas 5 had HR-negative status. Male breast cancer patients in this cohort have an incidence of prostate cancer higher than would be predicted in the general population; this risk factor has implications for careful prostate cancer screening.