[Comparison of cancer survival by age group for 1997 and for 2002: application of period analysis using the National Cancer Incidence Database].
OBJECTIVE
Period analysis estimates up-to-date survival rates of cancer patients. In this approach, analysis is restricted to recent time period by left-truncating all observations at the beginning of the period and right-censoring at its end. Here, we applied period analysis to examine changes in 5-year relative survival (RS) by age group for 1997 and for 2002.


METHODS
Using the National Cancer Incidence Database, 5-year RS was estimated for 1997 and 2002 in four age groups (15-54, 55-64, 65-74, and 75 years old and over) using period analysis. After excluding death certificate-only cases, patients with an unknown date of diagnosis or follow-up length, a total of 813,889 patients diagnosed with a first primary invasive cancer during 1992-2002 were included for analysis. Followup for vital status was included until 31 December 2002.


RESULTS
Five-year RS increased from 41.7% for 1997 to 46.7% for 2002. Increases in survival occurred in all age groups except in the 75 and over group.


CONCLUSIONS
The age gradient in cancer prognosis seems to have widened between 1997 and 2002, a finding that requires further study of prognostic factors, including stage at diagnosis. Period analysis accurately estimates survival rates, especially for cancers with better prognosis.
Yim
Seon Hee
SH
Cancer Registration and Biostatistics Branch, National Cancer Control Research Institute, National Cancer Center, Korea.
Jung
Kyu Won
KW
Won
Young Joo
YJ
Kong
Hyun Joo
HJ
Shin
Hai Rim
HR
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D005260:Female; D006306:Health Surveys; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D017741:Survivors / Q000706:statistics & numerical data*; D013997:Time Factors