Long-term colorectal-cancer mortality after adenoma removal

N Engl J Med. 2014 Aug 28;371(9):799-807. doi: 10.1056/NEJMoa1315870.

Abstract

Background: Although colonoscopic surveillance of patients after removal of adenomas is widely promoted, little is known about colorectal-cancer mortality among these patients.

Methods: Using the linkage of the Cancer Registry and the Cause of Death Registry of Norway, we estimated colorectal-cancer mortality among patients who had undergone removal of colorectal adenomas during the period from 1993 through 2007. Patients were followed through 2011. We calculated standardized incidence-based mortality ratios (SMRs) using rates for the Norwegian population at large for comparison. Norwegian guidelines recommended colonoscopy after 10 years for patients with high-risk adenomas (adenomas with high-grade dysplasia, a villous component, or a size ≥10 mm) and after 5 years for patients with three or more adenomas; no surveillance was recommended for patients with low-risk adenomas. Polyp size and exact number were not available in the registry. We defined high-risk adenomas as multiple adenomas and adenomas with a villous component or high-grade dysplasia.

Results: We identified 40,826 patients who had had colorectal adenomas removed. During a median follow-up of 7.7 years (maximum, 19.0), 1273 patients were given a diagnosis of colorectal cancer. A total of 398 deaths from colorectal cancer were expected and 383 were observed, for an SMR of 0.96 (95% confidence interval [CI], 0.87 to 1.06) among patients who had had adenomas removed. Colorectal-cancer mortality was increased among patients with high-risk adenomas (expected deaths, 209; observed deaths, 242; SMR, 1.16; 95% CI, 1.02 to 1.31), but it was reduced among patients with low-risk adenomas (expected deaths, 189; observed deaths, 141; SMR, 0.75; 95% CI, 0.63 to 0.88).

Conclusions: After a median of 7.7 years of follow-up, colorectal-cancer mortality was lower among patients who had had low-risk adenomas removed and moderately higher among those who had had high-risk adenomas removed, as compared with the general population. (Funded by the Norwegian Cancer Society and others.).

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenoma / mortality
  • Adenoma / surgery*
  • Adult
  • Aged
  • Aged, 80 and over
  • Colorectal Neoplasms / mortality*
  • Colorectal Neoplasms / prevention & control
  • Colorectal Neoplasms / surgery
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Norway / epidemiology
  • Registries
  • Risk