Germline Testing for Men with Prostate Cancer: Need to Broaden the Indications in Europe?

383 Background: The clinical role of germline testing (GT) for prostate cancer (PC) is rapidly increasing due to the growing implications of precision medicine in metastatic disease, where genetic results can address eligibility for novel targeted treatments. Thus, ESMO and NCCN guidelines recommend GT for all metastatic PC individuals, whereas American testing criteria are more broad and include family history and other tumor features, such as high-risk disease, or intraductal or cribriform histology. Methods: We have retrospectively collected and analyzed clinical and genetic features of men with PC who underwent single-gene or multi-gene GT at some Swiss Institutions with expertise in hereditary cancers from July 2018 until October 2022. All patients (pts) have given written informed consent for research. Results: 109 men with PC underwent GT and received pre- and post-test counseling. Of these, 54 (50%) were metastatic, 34 (31%) had high-risk localized disease according to NCCN criteria, 7 (6%) presented cribriform or intraductal histology. A significant family history, as defined by current NCCN guidelines, was found in 79 (72%). 67 (61%) had no pathogenic (P) or likely pathogenic (LP) variants; 25 (23%) had a variant of unknown significance (VUS); 17 (16%) were found to have a P/LP variant in the following genes: BRCA2 (8), ATM (4), BRIP1 (1), FANCA (1), NBN (1), POT1 (1), TP53 (1). Among these 17 pts, the median age at diagnosis was 66 (45-80), 10 had metastatic disease, 5 had high-risk localized disease, 14 had a family history and 5 had a personal history of another cancer. Only 6 pts were <60 years old at the time of diagnosis. Cascade screening was offered to 16 families (94%). Conclusions: Our preliminary data support the increasing role of GT in PC and suggest the need to expand its indications. In this cohort, 7/17 (41%) of men with localized PC were found to carry P/LP variants and would not have met the criteria to undergo GT according to current European guidelines. GT may have treatment implications for metastatic PC pts whereas in early stage disease can inform cancer risk and screening for pts and their male and female relatives.