Hereditary nonpolyposis colorectal cancer and colonic adenomas: Aggressive adenomas?

Hereditary nonpolyposis colorectal cancer (HNPCC) results from an inherited defect in one of the genes responsible for repair of errors that occur during DNA replication. Affected individuals have high risk for cancers of the colon and certain extracolonic sites. It appears that HNPCC patients form adenomas at about the same rate as the general population and there is circumstantial evidence that adenoma is the precursor to colorectal carcinoma in the syndrome. It is hypothesized that HNPCC features accelerated progression from colonie adenoma to carcinoma, a process theoretically driven by the inability to repair DNA mismatches. Evidence in support of the “Aggressive Adenoma” in HNPCC is provided. We discuss our recommendations for colono‐scopic surveillance on an annual basis for HNPCC gene‐positive individuals, and for genetic counseling. © 1995 Wiley‐Liss, Inc.