Reporting practices for secondary findings among ERN GENTURIS member institutions in 15 European countries.

Secondary findings (SF) identified in massive parallel sequencing raise important clinical and healthcare related questions. To get an overview on current practices of European healthcare providers (HCP), we conducted a cross-sectional survey study among 39 stakeholders-predominantly senior medical and laboratory geneticists-from 15 European countries participating in the European Reference Network for Genetic Tumour Risk Syndromes (ERN GENTURIS). Respondents reported considerable heterogeneity in SF management and reporting, even within countries. While 31% of responding HCP return findings from all 81 genes on the American College of Medical Genetics and Genomics (ACMG) recommended SF list version 3.2, 41% restrict SF disclosure, often excluding genes associated with cardiological or metabolic disorders or with limited clinical actionability. A further 26% do not report ACMG-listed SF at all. Notably, 70% of HCP also assess additional cancer-predisposition genes beyond the ACMG list, using in-house gene lists or national guidelines. Most HCP restrict reporting to (likely) pathogenic variants (90%) and find SF in less than 5% of genetic analyses (59%). Consent procedures and patient information practices varied, with most HCP employing opt-in consent models and genetic counselling primarily delivered by medical geneticists and genetic counsellors. Major institutional challenges raised by participants, include lack of harmonised guidelines, concerns about patient anxiety, and insufficient resources for follow-up care. The findings of this study highlight the need for robust, evidence-based European guidelines to ensure clinically relevant and patient-centred SF management.