Follow-up information of comprehensive cancer registries in Germany: valuable data with a solid evidence base

Background Along with the implementation of comprehensive cancer registries (CRs) in Germany, the amount of continuously collected follow-up information on therapy and outcomes concerning patients and their tumors has been substantially extended. Objectives This contribution aims to demonstrate new potential uses for the available follow-up information from CRs. It focuses on various statistical approaches and implications for oncological care as well as existing limitations. Materials and methods Data from the CRs of Hamburg and Saarland on cancers of pancreas, cervix and prostate diagnosed in the calendar period 2017-2021 were used. The survival of patients was analyzed by use of life table approaches, Kaplan-Meier estimators and Cox proportional hazard models. Furthermore, the cumulative risk of cancer recurrence was estimated. Results Overall 3-year survival of patients with adenocarcinoma of the pancreas ranged between 9 and 60%, according to stage, age, sex, place of residence and surgery. For patients with invasive cervical cancer, the recorded mortality was 0.5-fold if not resident in the CR's catchment area. Patients with radical prostatovesiculectomy and free margins had a 2.6-fold risk of tumor recurrence if the tumor had penetrated the prostatic capsule. Conclusions After expansion of CRs, detailed information on tumors, cancer treatment and follow-up care, which are valuable for both oncological care and scientific research, are available. To obtain meaningful and relevant results, however, analyses ought to be adjusted to clinical subgroups, cancer-specific lethality and type of outcome to avoid spurious correlations.