Cancer Incidence and Survival among Adolescents and Young Adults in Korea

BACKGROUND In Korea, cancer is the third leading cause of death among adolescents and young adults (AYAs). However, cancer incidence and survival trends among AYAs (15-29 years) have never been studied in Korea. Therefore, this study aimed to investigate the incidence and relative survival rates and their trends among AYAs in Korea. MATERIALS AND METHODS Cancer incidence data from 1999-2010 were obtained from the Korea Central Cancer Registry (KCCR). Each cancer was classified into subgroups according to the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) AYA site recode. Percent distributions, age-specific incidence rates, age-standardized incidence rates per million, and annual percent changes (APCs) were calculated for AYAs according to sex. Five-year relative survival rates were estimated for cases diagnosed between 1993 and 2010 and followed up to 2011. RESULTS The age-standardized incidence rates of all cancers combined were 196.4 and 367.8 per million for males and females, respectively (male-to-female (M/F) ratio: 0.5). The age-standardized incidence rates increased from 208.7 per million in 1999 to 396.4 per million in 2010, and the APC was 6.3% (P<0.001). The five most common cancers among AYAs were thyroid carcinoma, non-Hodgkin lymphoma, stomach carcinoma, breast carcinoma, and acute myeloid leukemia. In males, the 5-year relative survival rate improved, from 46.5% in 1993-1995 to 75.9% in 2006-2010. In females, the 5-year relative survival rate also improved, from 66.7% in 1993-1995 to 89.1% in 2006-2010. CONCLUSIONS Our study showed increases in cancer incidence and improvements in the 5-year relative survival rate among Korean AYAs. This study also provides additional data regarding temporal and geographic trends in cancer that may enhance future efforts to identify factors affecting cancer incidence and responses to treatment among AYAs.