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Article History

Received: 24 October 2025

Accepted: 15 July 2026

First Online: 24 July 2026

Declarations

Ethics and consent to participate declarations: This study used aggregated, non-identifiable data from the Netherlands Cancer Registry (NCR). Access to the data was granted by the Netherlands Comprehensive Cancer Organisation (IKNL) following approval of the application K22.267 (“Application Form for NCR Data”), in accordance with the Toetsingskader Gegevensaanvragen NKR (NCR Data Request Assessment Framework) and the Algemene Voorwaarden NKR-gegevensleveringen (General Terms and Conditions of NCR Data Provision). According to Dutch law and NCR governance rules, research using fully anonymized or aggregated NCR data does not require review by a Medical Research Ethics Committee under the Medical Research Involving Human Subjects Act (WMO). Accordingly, IKNL confirmed that formal ethics committee approval was not required, and the need for ethics approval was therefore waived. All procedures were carried out in accordance with the principles of the Declaration of Helsinki. Because the NCR data provided to the investigators were fully anonymized and not traceable to individual patients (as specified in Section H of the NCR Data Application), informed consent from participants was not required, in line with Dutch national regulations governing secondary use of registry data. Individual patient consent was therefore waived.

Consent for publication: Not applicable.

Competing interests: The authors declare no competing interests.