[The parameter "relative survival": Analysis of regional cancer registry data for prostate cancer]

There is a lack of comparability of relative survival rates due to differences in regional mortality.

How should relative survival be calculated to be able to compare regional cancer mortality?

Calculation of relative survival rates of prostate cancer patients from a regional cancer registry using diagnosis year and stage, based on differential mortality tables.

Calculation of relative survival for all prostate cancer patients shows a very slight excess mortality after 5 years compared to a matched general population. Introduction of new imaging techniques and PSA screening led to a change in the distribution of diagnosed stages. Differentiation by stage is therefore essential. Thus, patients with UICC stage I, II, and III have a very low excess mortality, while patients with a UICC stage IV have a significantly higher excess mortality; however, it is very surprising that the excess mortality of patients without specification of the UICC stage is similarly unfavorable as in the case of patients with UICC stage IV.

If data from a regional cancer registry are used, adequate mortality tables from the catchment area of the registry should be used as a reference due to regional mortality differences. Thus, progress in patient survival can be more precisely mapped. With respect to prostate cancer patients, differential consideration by stage is also necessary because improved early detection methods has led to a change in the stage distribution and, thus, survival.