Ongoing colorectal cancer risk despite surveillance colonoscopy: the Polyp Prevention Trial Continued Follow-up Study

Received 15 December 2008; accepted 4 May 2009. published online 03 August 2009.

Refers to article:

Continuing Medical Education Exam: January 2010
Raquel E. Davila, Jeffrey H. Lee, William Ross, Shou-Jiang Tang, G.S. Raju, George Triadafilopoulos
Gastrointestinal Endoscopy
January 2010 (Vol. 71, Issue 1, Pages 139-139.e6)
Full-Text PDF (5226 KB)

Background

Despite regular colonoscopy, interval colorectal cancer (CRC) may occur. Long-term studies examining CRC rates in patients with previous colonoscopy are lacking.

Objective

We examined the rate of interval CRC in the Polyp Prevention Trial Continued Follow-up Study (PPT-CFS), an observational study of PPT participants that began after the PPT ended.

Design

Prospective.

Setting

A national U.S. community-based polyp prevention trial.

Main Outcome Measurements

Medical records of patients with CRC were collected, reviewed, and abstracted in a standardized fashion.

Results

Among 2079 PPT participants, 1297 (62.4%) agreed to participate in the PPT-CFS. They were followed for a median of 6.2 years after 4.3 years of median follow-up in the main PPT. Nine cases of CRC were diagnosed over 7626 person-years of observation (PYO), for an incidence rate of 1.2/1000 PYO. The ratio of CRCs observed compared with that expected by Surveillance, Epidemiology, and End Results was 0.64 (95% CI, 0.28-1.06). Including all CRCs (N = 22) since the beginning of the PPT, the observed compared with expected rate by Surveillance, Epidemiology, and End Results was 0.74 (95% CI, 0.47-1.05). Of patients in whom CRC developed in the PPT-CFS, 78% had a history of an advanced adenoma compared with only 43% of patients who remained cancer free (P = .04).

Limitation

A relatively small number of interval cancers were detected.

Conclusions

Despite frequent colonoscopy during the PPT, in the years after the trial, there was a persistent ongoing risk of cancer. Subjects with a history of advanced adenoma are at increased risk of subsequent cancer and should be followed closely with continued surveillance.

Pittsburgh, Pennsylvania, Bethesda, Maryland, USA

Abbreviations: CFS, Continued Follow-up Study, CRC, colorectal cancer, PPT, Polyp Prevention Trial, PYO, person-years of observation, SEER, Surveillance, Epidemiology, and End Results

Current affiliations: Department of Medicine (K.L., R.E.S.), Department of Epidemiology and University of Pittsburgh Cancer Institute (R.E.S.), University of Pittsburgh, Pittsburgh, Pennsylvania, Division of Cancer Prevention (P.P.), Cancer Prevention Fellowship Program (A.O.L.), Laboratory of Cancer Prevention (E.L.), Division of Cancer Epidemiology and Genetics (A.S.), National Cancer Institute, Bethesda, Maryland, USA

Reprint requests: Robert E. Schoen, MD, MPH, Division of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Mezzanine Level, C Wing, 200 Lothrop St, Pittsburgh, PA 15213-2582.

DISCLOSURE: All authors disclosed no financial relationships relevant to this publication.

See CME section; p. 139.

PII: S0016-5107(09)01912-9

doi:10.1016/j.gie.2009.05.010

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