Cancer statistics for young adults aged 20 to 49 years in China from 2000 to 2017: a population-based registry study

An increasing cancer incidence among adults younger than 50 years has been reported for several types of cancer in multiple countries. We aimed to report cancer profiles and trends among young adults in China. Data from the China Cancer Registry Annual Report were used to estimate incidence and mortality among young adults (ages 20–49 years) in China in 2017, and an age-period-cohort model was employed to estimate the average annual percent change (AAPC) in incidence and mortality from 2000 to 2017. All 25 cancer types were grouped into obesity- or overweight-associated cancers (12 cancer types) and additional cancers (13 cancer types). In 2017, there were 681,178 new cases and 214,591 cancer deaths among young adults in China. Among young adults, the most common cancers were thyroid, breast, cervical, liver, lung, and colorectal cancer, and the leading causes of cancer deaths were liver, lung, cervical, stomach, breast, and colorectal cancer. From 2000 to 2017, the cancer incidence increased for all cancers combined among young adults, with the highest AAPC (1.46%) for adults aged 20–24 years, while cancer mortality decreased, with the highest AAPC (−1.63%) for those aged 35–39 years. In conclusion, the cancer incidence in China has increased among young adults, while cancer mortality has decreased for nearly all ages. Cancer control measures, such as obesity control and appropriate screening, may contribute to reducing the increasing cancer burden among young adults.