Genetics of Colorectal Cancer (PDQ®)–Health Professional Version

SECTIONS

Changes to This Summary (11/22/2017)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Introduction

The Colorectal Polyps as Precursors to Colorectal Cancer (CRC)subsection was renamed from Precursors of Colorectal Polyps.

Revised text to state that as susceptibility to oligopolyposis has become apparent, clinicians, and gastrointestinal endoscopists in particular, may consider multigene (panel) testing of an ever-expanding list of genes associated with CRC.

Revised Figure 2, Lynch syndrome pedigree, to state that the pedigree shows some of the classic features of a family with Lynch syndrome, including affected family members with colon cancer or endometrial cancer, a young age at onset in some individuals, and incomplete penetrance; because the cancer risk is not 100%, individuals who have Lynch syndrome may not develop cancer, such as the mother of the female with colon cancer diagnosed at age 37 years in this pedigree.

Major Genetic Syndromes

Added text about a cost-effectiveness analysis that was performed using data from 179 consecutive endometrial cancer patients diagnosed at or before age 70 years and screened with mismatch repair (MMR) immunohistochemistry and reflex MLH1 promoter hypermethylation, among whom seven Lynch syndrome carriers were identified (cited Goverde et al. as reference 311). Also added text about the cost-effectiveness of universal tumor testing in both CRC and endometrial cancer which is largely driven by the assumption of cascade screening through which other at-risk family members will be identified, tested, and subsequently pursue their own cancer risk reduction.

Added text about a study of 242 consecutive endometrial cases that demonstrated a 4.5% prevalence of MMR-deficient cases lacking somatic MLH1 promoter hypermethylation, including four cases with germline MMR mutations, four cases with two somatic MMR alterations on next-generation sequencing, and two cases with otherwise unexplained MMR-deficiency (cited Watkins et al. as reference 320); such findings demonstrate that universal MMR tumor screening of endometrial cancers will identify individuals with underlying Lynch syndrome and a spectrum of non-Lynch syndrome cases with various forms of MMR-deficiency.

Added NCCN as reference 541.

This summary is written and maintained by the PDQ Cancer Genetics Editorial Board, which is editorially independent of NCI. The summary reflects an independent review of the literature and does not represent a policy statement of NCI or NIH. More information about summary policies and the role of the PDQ Editorial Boards in maintaining the PDQ summaries can be found on the About This PDQ Summary and PDQ® - NCI's Comprehensive Cancer Database pages.

< Previous section
Psychosocial Issues in Hereditary Colon Cancer Syndromes

Next section >
About This PDQ Summary