Opportunistic genomic screening has clinical utility: An interventional cohort study.

Background: Practice is shifting toward genome-first approaches, such as opportunistic screening for secondary findings (SFs). Analysis of SFs could be extended beyond medically actionable results to include non-medically actionable monogenic disease risks, carrier status, pharmacogenomic variants, and risk variants for common complex disease. However, evidence on the clinical utility of returning these results is lacking. We assessed the outcomes of opportunistic screening for a broad spectrum of SFs by evaluating the yield, impact on clinical management, and consistency between SFs and participants' clinical features and family history.

Methods: Adult cancer patients had GS with the option to learn multiple categories of SFs. Outcomes data were collected through chart review and participant-reported measures up to one year after return of results.

Results: All participants (n=139, 85.6% female, average 54.6 years old) who elected to learn SFs had ≥1 variant reported (100% [139/139]). The yield of reportable findings was highest for pharmacogenomic variants (97.8% [135/138] of participants), followed by common disease risk variants (89.4% [118/132]), carrier status (89.3% [117/131]), and variants related to Mendelian (27.2% [34/125]), medically actionable (15.2% [21/138]), and early-onset neurodegenerative (2.6% [3/117]) disease risks. SFs from the ACMG list (v3.2, non-cancer genes) were reported in 1.4% (2/138) of participants. SFs across all categories demonstrated clinical utility by prompting management changes in 28.1% (39/139) of participants. Moreover, a considerable proportion of participants had suggestive clinical features (49.0% (24/49)]) or family history (21.8% (27/124)) potentially related to their SFs.

Conclusions: Our findings indicate there are potential benefits from opportunistic screening for a broad range of SFs.