Abstract
BackgroundWe previously reported that in pathogenic mismatch repair (path_MMR) variant carriers, the incidence of colorectal cancer (CRC) was not reduced when colonoscopy was undertaken more frequently than once every 3 years, and that CRC stage and interval since last colonoscopy were not correlated.MethodsThe Prospective Lynch Syndrome Database (PLSD) that records outcomes of surveillance was examined to determine survival after colon cancer in relation to the time since previous colonoscopy and pathological stage. Only path_MMR variants scored by the InSiGHT variant database as class 4 or 5 (clinically actionable) were included in the analysis.ResultsNinety-nine path_MMR carriers had no cancer prior to or at first colonoscopy, but subsequently developed colon cancer. Among these, 96 were 65 years of age or younger at diagnosis, and included 77 path_MLH1, 17 path_MSH2, and 2 path_MSH6 carriers. The number of cancers detected within < 1.5, 1.5–2.5, 2.5–3.5 and at > 3.5 years after previous colonoscopy were 9, 43, 31 and 13, respectively. Of these, 2, 8, 4 and 3 were stage III, respectively, and only one stage IV (interval 2.5–3.5 years) disease. Ten-year crude survival after colon cancer were 93, 94 and 82% for stage I, II and III disease, respectively (p < 0.001). Ten-year crude survival when the last colonoscopy had been < 1.5, 1.5–2.5, 2.5–3.5 or > 3.5 years before diagnosis, was 89, 90, 90 and 92%, respectively (p = 0.91).ConclusionsIn path_MLH1 and path_MSH2 carriers, more advanced colon cancer stage was associated with poorer survival, whereas time since previous colonoscopy was not. Although the numbers are limited, together with our previously reported findings, these results may be in conflict with the view that follow-up of path_MMR variant carriers with colonoscopy intervals of less than 3 years provides significant benefit.
Highlights
We previously reported that in pathogenic mismatch repair variant carriers, the incidence of colorectal cancer (CRC) was not reduced when colonoscopy was undertaken more frequently than once every 3 years, and that CRC stage and interval since last colonoscopy were not correlated
In path_MLH1 and path_MSH2 carriers, more advanced colon cancer stage was associated with poorer survival, whereas time since previous colonoscopy was not
The numbers are limited, together with our previously reported findings, these results may be in conflict with the view that follow-up of path_MMR variant carriers with colonoscopy intervals of less than 3 years provides significant benefit
Summary
Because the current prospective evidence suggests that annual colonoscopies compared to three yearly colonoscopies do not benefit path_MMR carriers in terms of CRC incidence or earlier cancer stage at diagnosis, we aimed to determine if survival after colon cancer differs according to the intervals of colonoscopies undertaken prior to cancer diagnosis in path_MMR carriers
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