Survival of Korean Adult Cancer Patients by Stage at Diagnosis, 2006-2010: National Cancer Registry Study

Purpose Although the cancer stage at diagnosis is the most important prognostic factor for patients' survival, there are few population-based estimates of stage-specific survival outcome, especially in Asian countries. Our study aims to estimate stage-specific survival for Korean patients. Materials and Methods We analyzed the Korea National Cancer Incidence Database data on 626,506 adult patients aged >= 20 years, who were diagnosed between 2006 and 2010 with stomach, colorectal, liver, lung, breast, cervix, prostate, and thyroid cancers. Patients were followed up to December 2011, and the 5-year relative survival rates (RSRs) were calculated for gender and age group by Surveillance, Epidemiology, and End Results (SEER) stage at diagnosis. Results The 5-year RSRs for all localized-stage cancers, except for lung and liver, exceeded 90% with that for thyroid cancer being the highest at 100.4%. These values for distant stage liver, lung, and stomach cancers were very dismal at 2.5%, 4.8%, and 5.5%, respectively, while it was 69.1% for thyroid cancer, and was in the range of 18.3-36.4% for colorectal, cervix, breast and prostate cancers. Overall, the 5-year RSRs for all cancer types decreased with aging across all the disease stages with exception of prostate cancer, which suggests biologic difference in these cancer types in a young age group. When compared with US SEER data, Korean patients had better stage-specific survival rates for stomach, colorectal, liver, and cervical cancers. Conclusion Korean cancer patients showed relatively favorable stage distribution and 5-year RSRs, which suggests potential contribution of the national cancer screening program.