Descriptive epidemiology of male breast cancer in Japan

To examine the characteristics of male breast cancer in Japan, time trends and geographical distribution of the mortality of male breast cancer were analyzed by using "Vital Statistics" over the last four decades, compared with female breast cancer mortality. The male to female sex ratio of the number of deaths from breast cancer over the period between 1950-1994 was 1:103.6. The age-specific death rates of breast cancer in males rose steadily with age while the rates in females having the peak in the latter half of the sixth decade, then decreasing, rising again in the ninth decade for the years 1973-1993. The number of deaths from breast cancer has increased, and while the crude death rate has risen from 1948-1952 to 1988-1992 in both sexes, and the increasing trend in females was larger than that in males in recent years. On the other hand, the age-adjusted death rate from breast cancer has leveled off or decreased in males while the rate in females has increased over the last few decades. Thus, the female to male sex ratios of both the number of deaths and the death rates from breast cancer increased continuously in recent years. The average age at death from breast cancer in males gained 11.7 years during the last 40 years (71.2 years old in 1988-1992 vs 59.5 years in 1948-1952), but only 3.1 years in females (58.6 vs 55.5).