Determine the proportion of patients with Lynch syndrome who received guideline-concordant care according to NCCN guidelines during the study period (2015–2018).

A retrospective cohort study was performed at Kaiser Permanente Northern California including patients with germline pathogenic variants in MLH1, MSH2/EPCAM, MSH6 or PMS2 tested between 01/01/2015 and 12/31/2018. Clinical and demographic characteristics were abstracted from chart review. Screenings were assessed for gynecologic, gastrointestinal (GI), urinary, skin, and neurologic cancer sites. Concordance was assessed against NCCN guidelines (versions 1.2015 through 1.2018) matched to the year of each patient encounter. The primary outcome was receipt of guideline-concordant care. Secondary outcomes included rates of under- and over-utilization and clinical/demographic factors associated with care utilization.

We identified 234 patients: 46 with pathogenic MLH1 variants, 64 with MSH6, 83 with PMS2 and 41 with MSH2/EPCAM variants. Median age was 52 years (IQR: 39–62), most were white (60%) and 29% were tested based on a personal cancer history. Half (48%) of patients received screening as recommended by NCCN guidelines, with highest concordance for GI cancer screening. A quarter of patients received less screening than recommended by guidelines. Patients with MLH1 variants had higher rates of transvaginal ultrasound (34.2%) and urologic cancer screening (28.3%) compared to those with other variants.

Only 48% of patients in this integrated healthcare system received guideline-concordant Lynch syndrome surveillance. Our findings highlight variation in screening practices across pathogenic variant types and suggest opportunities for improving adherence to recommended screenings within healthcare systems.