Prevalence of Cancer Survivors in 2019 Among Patients Diagnosed Between 1975 and 2019: A Population-Based Study in Japan.

Owing to improved prognosis, cancer survivors are a growing population; however, little is known about their prevalence in Asian countries. This study estimated the prevalence and characteristics of cancer survivors in Japan, including long-term survivors. Using data from the Osaka Cancer Registry, which covers 8.8 million residents in Osaka Prefecture, Japan, we identified individuals diagnosed with cancer between 1975 and 2019 who were alive in 2019. Cancer prevalence was calculated as the number of patients alive in 2019, stratified by sex, age in 2019, time since diagnosis, and 22 cancer types. National estimates were obtained by applying sex- and age-specific prevalence proportions in Osaka to the Japanese population. In 2019, 461,489 cancer survivors were living in Osaka Prefecture (5.4% of the prefectural population; 5221 per 100,000). Most were older adults, with 83% of males (n = 188,881) and 70% of females (n = 163,331) aged ≥ 65 years in 2019. Long-term survivors (≥ 10 years after diagnosis) comprised 34% of all survivors. These patterns varied across cancer types. Nationally, an estimated 6.9 million individuals (5.5% of the national population) lived after a cancer diagnosis. Based on 44 years of follow-up data, our findings highlighted a substantial subgroup of cancer survivors requiring long-term treatment, follow-up care, and age-specific support. These findings may provide useful insights for healthcare planning and cancer survivor policies in aging societies.