Updated Trends in Cancer in Japan: Incidence in 1985-2015 and Mortality in 1958-2018-A Sign of Decrease in Cancer Incidence

Background: Unlike many North American and European countries, Japan has observed a continuous increase in cancer incidence over the last few decades. We examined the most recent trends in population-based cancer incidence and mortality in Japan.

Methods: National cancer mortality data between 1958 and 2018 were obtained from published vital statistics. Cancer incidence data between 1985 and 2015 were obtained from high-quality population-based cancer registries maintained by three prefectures (Yamagata, Fukui, and Nagasaki). Trends in age-standardized rates (ASR) were examined using Joinpoint regression analysis.

Results: For males, all-cancer incidence increased between 1985 and 1996 (annual percent change [APC] +1.1%; 95% confidence interval [CI], 0.7-1.5%), increased again in 2000-2010 (+1.3%; 95% CI, 0.9-1.8%), and then decreased until 2015 (-1.4%; 95% CI, -2.5 to -0.3%). For females, all-cancer incidence increased until 2010 (+0.8%; 95% CI, 0.6-0.9% in 1985-2004 and +2.4%; 95% CI, 1.3-3.4% in 2004-2010), and stabilized thereafter until 2015. The post-2000 increase was mainly attributable to prostate in males and breast in females, which slowed or levelled during the first decade of the 2000s. After a sustained increase, all-cancer mortality for males decreased in 1996-2013 (-1.6%; 95% CI, -1.6 to -1.5%) and accelerated thereafter until 2018 (-2.5%; 95% CI, -2.9 to -2.0%). All-cancer mortality for females decreased intermittently throughout the observation period, with the most recent APC of -1.0% (95% CI, -1.1 to -0.9%) in 2003-2018. The recent decreases in mortality in both sexes, and in incidence in males, were mainly attributable to stomach, liver, and male lung cancers.

Conclusion: The ASR of all-cancer incidence began decreasing significantly in males and levelled off in females in 2010.