- After age 70-75 years, diagnostic accuracy of Lynch syndrome (LS) screening slips to the point of inefficiency.
Why this matters
- Guidelines recommend universal LS screening in patients with newly diagnosed colorectal cancer (CRC), but cost-efficacy and diagnostic yield have not been closely examined in elderly patients.
- Retrospective cohort study of 3891 patients diagnosed with CRC who had mismatch repair immunohistochemistry (MMR IHC) analysis performed at Kaiser Permanente Northern California.
- Funding: Kaiser Permanente Northern California.
- 63 cases of LS were identified through universal screening: 28 were aged ≤50 years, 18 were 51-60 years, 12 were 61-70 years, 4 were 71-80 years, and 1 was >80 years.
- The diagnostic yield of screening was 0.72% (95% CI, 0.48%-1.04%) if age 50 years was the upper cutoff. It increased to 1.54% (95% CI, 1.18%-1.98%) with a cutoff of 75 years and 1.59% (95% CI, 1.22%-2.04%) with an upper bound of 80 years.
- An age limit of 70 years would have missed 7.9% of LS cases, but led to a reduction of 38.5% in cases requiring tumor MMR IHC. Age 80 years would have missed 1.6% of LS cases, but 17.2% of patients would not have required MMR IHC.
- Retrospective study.