Incremental diagnostic yield decreases substantially after 70 to 75 years; LS is rare after 80 years
TUESDAY, June 11, 2019 (HealthDay News) — The incremental diagnostic yield of Lynch syndrome (LS) screening decreases substantially after age 70 to 75 years, according to a study published online June 11 in the Annals of Internal Medicine.
Dan Li, M.D., from Kaiser Permanente Northern California in Santa Clara, and colleagues compared the performance of age-restricted and universal LS screening using reflex mismatch repair (MMR) immunohistochemistry (IHC) of colorectal cancer (CRC) tumors in a retrospective cohort study. Data were included for 3,891 persons with newly diagnosed CRC who underwent LS screening between 2011 and 2016.
The researchers identified 63 LS cases (diagnostic yield, 1.62 percent) with universal screening, with five cases and one case (7.9 and 1.6 percent) detected after age 70 and 80 years, respectively. Using all patients with CRC with universal screening as the denominator, 58, 60, and 62 LS cases were identified in those with CRC diagnosed at or before age 70, 75, and 80 years, respectively (diagnostic yield, 1.49, 1.54, and 1.59 percent, respectively). Three of 63 LS cases were missed using 75 years as the upper age limit for screening, while 1,053 (27.1 percent) fewer cases required tumor MMR IHC. One LS case was missed and 668 (17.2 percent) fewer cases required tumor MMR IHC using 80 as the upper age limit.
“Age was a key determinant of LS screening performance using reflex MMR IHC on CRC tumors in a large community-based setting,” the authors write.
One author disclosed financial ties to the biopharmaceutical industry.
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