Survival of male breast cancer patients: population-based cohort study.

Little information is available on the survival of male breast cancer patients because the disease is extremely rare in men. Moreover, previous reports on the prognosis of male breast cancer have been conflicting. We took advantage of a number of large, nationwide registries in Sweden to evaluate the prognostic value of sex in breast cancer patients. A population-based cohort of 269 male and 30 011 female breast cancer patients born after 1935 and diagnosed with primary breast cancer between 1970 and 1997 was generated by linking a number of Swedish registries, including the Swedish Cancer Registry, the Cause of Death Registry, the Swedish Generation Registry, and the Registry of Population and Population Changes. We used this cohort to quantify the association between the sex of the patient and breast cancer-specific mortality, using the Cox proportional hazards. The sex of the patient did not significantly influence the prognosis of breast cancer. Adjusting for age at diagnosis and calendar period did not alter the results. Nor did the results change when the analyses were repeated for all causes of morality. Our study, one of the largest to date, failed to find evidence to support the proposed association between the sex of breast cancer patients and survival. Given the previous reports, which advocated that male breast cancer patients have poorer survival and need aggressive treatment strategies, our findings are reassuring and clinically very important.