233P Germline genetic testing before formal counseling: Impact in cancer management in a Spanish university hospital

Performing rapid genetic testing before consultation in a Hereditary Cancer Unit (HCU) is becoming increasingly common due to its importance in the decision-making of cancer management. There are few studies analyzing this new genetic counseling approach. We conducted a retrospective descriptive study in a cohort of patients (pts) who underwent germinal genetic testing during their treatment plan at Hospital Gregorio Marañon since April 2019 to November 2022. Tests were directly ordered by their oncologists with a brief pre-test counseling prior to the formal evaluation in the HCU. Primary objective was to analyze if having these results available prior to formal genetic counseling could impact in the management of the patient’s cancer. 225 pts (32.9% men, 67.1% women) underwent genetic test. Cancer diagnoses were: pancreatic (49.3%), breast (40.4%), ovarian (5.8%), colorectal (2.6%), gastric (2.6%), prostate (1.3%), cholangiocarcinoma (1.3%), renal (1.3%) and endometrial 0.9%. A specific-syndrome genetic panel was performed in 55.1%, multigenetic in 44% and single gene in 0.9%. We found pathogenic/likely pathogenic variants (PV/LPV) in 31 pts (13.8%) and variants of unknown significance (VUS) in 53 (23.5%). 22.6% of the pts with PV/LPV (n=7) didn't meet the Spanish Society for Medical Oncology (SEOM) criteria for hereditary cancer. 40% of the pts (n=90) didn´t receive post-test counseling in the HCU: 81.1% due to negative result and non-significant familial background, 10% due to patient's death, 4.4% did not attend the appointment (rest unknown). According to retrospective chart review in 32.3% with PV/LPV (n=10; 4.4% of the total) a change in cancer management was decided (Table).Table: 233PPts with PV/LPV (n=31)n (%)Changes in cancer management*Bilateral mastectomy8 (25.8%)Avoid radiotherapy1 (3.2%)PARP inhibitors1 (3.2%)Platinum-based chemotherapy2 (6.4%)None (due to death)(22.6%)*One patient could have more than one change Open table in a new tab *One patient could have more than one change Genetic testing performance can modify the therapeutic plan of pts with cancer, especially for those with PV/LPV. Rapidity in obtaining the results is essential. The balance between this rapidity and a proper post-test genetic counseling needs to be warranted.