(P 218) THE IMPACT OF BROADENED GENETIC COUNSELLING REFERRAL CRITERIA IN SARCOMA PATIENTS: A REFERENCE CENTRE'S EXPERIENCE

Objective: Although most sarcomas are sporadic, up to 20% of patients meet criteria for suspected hereditary cancer predisposition, mainly TP53-related cancer syndrome. Germline pathogenic variants (PVs) are found up to 8-20% of analysed cases, including many who do not meet strict referral criteria, suggesting the need to expand referrals to Hereditary Cancer Counseling (HCC) unit.

The objective of this study is to evaluate the impact on diagnostic and preventive clinical management following the implementation of broadened referral criteria at our center in 2023, which includes referring all patients with sarcoma under 45 years.

Methods: Retrospective observational study of a cohort of consecutive patients diagnosed with sarcoma and referred to HCC unit of a reference center between January 2007 and April 2025. Germline testing was performed according to clinical practice.

Results: Between 2007 and 2022, 22 patients diagnosed with sarcoma were referred to HCC unit. The median age was 46.5 years, and all met the established criteria for germline testing. PVs were identified in nine patients (40.9%).

From January 2023 to April 2025, a total of 115 patients were referred to HCC unit. The median age was 37 years, with 71.3% of patients younger than 45 years. Women accounted for 54.8% of the referred individuals. Of these patients, 41 met the criteria for suspected hereditary cancer predisposition (85.4% were suspected of having TP53-related cancer syndrome).
Germline testing was performed on 71 patients; 33 of them (46.5%) did not meet the strict criteria for suspicion. Germline PVs were found in 9.9% (seven patients): 13.2% of those who strictly met the criteria and 6% of those who did not. The PVs identified were: POT1 in one patient, TP53 in two patients, MUTYH in one patient, NF1 in one patient, RB in one patient and MSH6 in one patient. Of these seven patients, two (28.6%; both with TP53 PVs) did not strictly meet the criteria for germline testing.

Conclusion: The expansion of referral criteria to the Hereditary Cancer Counseling (HCC) unit to include all patients under 45 years of age has resulted in an increase in germline testing and PVs detection. This approach has significantly influenced clinical management and follow-up.