Correspondence: Estimating Cancer Risks From a Retrospective Cohort of Patients With MMR Gene Mutations

 Correspondence

 TO THEEDITOR:
Engel et al1 recently provided age-specificcumulative
risks of less common cancers (ie, noncolorectal and nonendometrial)
in Lynch syndrome. Using the Kaplan-Meier method, risks
were estimated by age, sex, and mutated genes in a large German and
Dutch cohort of 2,118 patients who were proven carriers of MLH1,
MSH2, and MSH6 mutations. The authors stated that ascertainment
bias should not have severely affected their estimates because most families were identified by clustering or early onset of colorectal or endometrial cancer. However, selection of patients from the German and Dutch national Lynch syndrome registries was based on Amsterdam criteria and Bethesda guidelines, which include tumors from the whole Lynch syndrom spectrum. We are therefore concerned that a potential bias in cancer-risk estimates may have been introduced by the fact that certain rarer tumors contributed to the recruitment of families......