Purpose We applied the average lifespan shortened (ALSS) measure to examine lifespan’s changes among individuals who died from malignancies of the central nervous system (CNS) in Japan from 2000 to 2020.
Methods Mortality data due to CNS cancers were obtained from the World Health Organization Mortality Database. Years of life lost (YLL) were calculated using Japanese life tables. ALSS was calculated as the ratio between YLL and the expected lifespan, and its 95% confidence interval (95% CI) was calculated using the bootstrap method.

Results Over the study, the age-standardized mortality rates adjusted to the World Standard Population due to CNS cancers increased from 1.0 to 1.3 deaths per 100,000 men and from 0.7 to 0.9 deaths per 100,000 women. ALSS results indicated that men with CNS malignancies lost 30.7% (95% CI: 29.2–32.2) of their lifespan in 2000, and 24.3% (95% CI: 23.4–25.3) in 2020. Similarly, ALSS values for women decreased from 32.9% (95% CI: 31.3–34.5) to 25.2% (95% CI: 24.1–26.3) over the same period.

Conclusion Our study revealed a gain in lifespan of individuals with CNS cancers in both sexes in Japan over the 20-year period.