Survival of male breast cancer patients: A population-based study in Osaka, Japan

Background: Little information is available on the survival of male breast cancer patients because the disease is extremely rare in men. Recent studies indicated there were no gender-differences in the 5-year survival if patients' age and stage were matched. However, this problem has rarely been studied in Japan. Methods: Using the Osaka Cancer Registry's data, the 5-year survival was analyzed based on the reported 19 869 cases who lived in Osaka Prefecture excluding Osaka City and were diagnosed in 1975-1997, or who resided in Osaka City and were diagnosed in 1993-1997, because reliable follow-up information was available for them. Results: Breast cancer in males accounted for 0.49% of all cases during 1975-1997. The 5-year relative survivals were 71.1% in men and 81.6% in women. The survival in males decreased over older groups due to a lower proportion of localized stage, but not in females. The survival of males in the regional stage was significantly lower than that of females (49.1 versus 73.7%, P < 0.05). Survival of males has increased since 1980-1984, while it has been stable in females. Compared with the survival of patients diagnosed in 1975-1979, male patients diagnosed in 1995-1997 had a noticeably lower risk of death after adjusting for age and cancer stage. Conclusions: The results suggest male breast cancer patients at the regional stage had a worse 5-year survival rate compared to females. However, this gender-related difference seems to have disappeared with the increased survival of males during the 1990s. Further population-based studies are required with a greater number of male patients diagnosed after 1990.