There are two main ways of quantifying survival estimates after cancer diagnosis. The conventional method, known as the cohort method, is based on the survival experience of cancer patients whose diagnosis occurred many years ago. This method therefore fails to disclose recent improvements in cancer detection and treatment. A recently developed alternative survival assessment-called period analysis-provides more up-to-date estimates of cancer survival, as it exclusively uses survival data from a specific time period, such as a particular year.
Hermann Brenner from the German Centre for Research on Ageing, Heidelberg, Germany, compared survival estimates obtained with period analysis (for the year 1998) and cohort analysis (for patients diagnosed between 1978 and 1993) using data from the US population based cancer registries.
Estimates of 5-year, 10-year, 15-year, and 20-year relative survival rates for all types of cancer were 63%, 57%, 53%, and 51%, respectively, by period analysis. These estimates were 1%, 7%, 11%, and 11% higher, respectively, than corresponding estimates by cohort-based survival analysis. By period analysis, 20-year relative survival rates were close to 90% for thyroid and testicular cancer, exceeded 80% for melanomas and prostate cancer, were about 80% for endometrial cancer, and almost 70% for bladder cancer and Hodgkin's disease. A 20-year relative survival rate of 65% was estimated for breast cancer, of 60% for cervical cancer, and of about 50% for colorectal, ovarian, and kidney cancer.
Hermann Brenner comments: "The provision of up-to-date long-term survival rates is not merely an academic exercise-it could help to prevent clinicians and their patients from undue discouragement or depression by outdated and often overly pessimistic survival expectations. Timely detection of improvements in long-term survival rates also adds to the value of cancer surveillance as a basis for appropriate public-health decisions."
Contact: Professor Hermann Brenner, Department of Epidemiology,Deutsches Zentrum fur Alternsforschung (DZFA),Bergheimer Strasse 20,D-69115 Heidelberg,Germany;T) +49 6221 54 8140;F)+49 6221 54 8142;E) brenner@dzfa.uni-heidelberg.de
Journal
The Lancet