Impact of an immunohistochemistry-based universal screening protocol for Lynch syndrome in endometrial cancer on genetic counseling and testing

Objective. Evaluate effects of a Lynch syndrome universal screening protocol in newly diagnosed endometrial cancers on subsequent genetic counseling (GC) and germline testing (GT) referral and acceptance rates. Methods.Weperformed a retrospective cohort study ofwomenwho underwent a hysterectomy for endometrial cancer at Barnes Jewish Hospital in St. Louis, MO between 1/1/2011 and 12/31/2013 (n = 637). An immunohistochemistry-based (IHC) universal screening protocol for Lynch syndrome was initiated on 12/17/ 2012. The cohorts consisted of women presenting prior to (Pre-Em-USP; n=395) and those presenting following (Em-USP; n = 242) initiation of the universal screening protocol. GC and GT referrals were based on risk factors and/or IHC results. Comparisons were made using the Fisher's exact test and the Kruskal-Wallis test. Results. A greater proportion of individuals in the Em-USP cohort underwent GT than in Pre-Em-USP (9.1% vs 4.8%, p < 0.05). Of individualswith an IHC screening result suggestive of LS, thosewithin the Em-USP cohortwere significantly more likely to accept GC compared to those in the Pre-Em-USP cohort (95% vs 64%, p=0.02). Specificallywithin the Em-USP cohort, patients referred to GC due to a concerning IHC screening result, versus those who were referred based on other risk factors, had a higher counseling acceptance rate (95% vs 61%, p = 0.03) and underwent genetic testing more readily (76% vs 30%, p < 0.001). Conclusions. Implementation of an IHC-based universal screening protocol for LS in endometrial cancer leads to higher acceptance of genetic counseling and higher rates of genetic testing compared to referral based on risk factors alone.