Availability of Stage Information From Cancer Registries Providing Data to the European Cancer Information System for Six Selected Cancers.

Cancer stage at diagnosis is crucial to guide clinical decision making and support cancer surveillance, enabling meaningful international comparisons of epidemiological cancer indicators and evaluation of cancer control policies. The collection of stage information by population-based cancer registries (PBCRs) is therefore essential, yet a comprehensive overview of stage availability across European PBCRs has been lacking. We analyzed the availability and completeness of stage at diagnosis reported by PBCRs affiliated with the European Network of Cancer Registries (ENCR) in the 2022 European Cancer Information System (ECIS) data call. The assessment focused on six major cancers, that is, breast, cervix, colorectum, gastric, lung, and prostate. Between 1990 and 2022, 67 (78%) PBCRs from 18 countries-out of 86 registries submitting incidence data to ECIS by September 2025-provided information on stage. Sixty-five (97%) used the Tumor-Nodes-Metastasis (TNM) system, although four coded a substantial proportion of cases using other staging systems. Many countries showed improvements over time in reporting TNM stage. In the period 2017-2019, in most countries more than 80% of breast, cervical, colorectal, and lung cancer cases had TNM information, while gastric and prostate cancers exceeded 70%. Nevertheless, a few countries reported TNM stage for less than half of their cases. Overall, stage at diagnosis is available for a large proportion of cancer cases in Europe, demonstrating the commitment of PBCRs to high-quality data collection. However, important gaps persist in some countries. Continued cooperation between the ENCR and ECIS is needed to support harmonized stage reporting across European registries.