Six-Year Interval ‘Appropriate’ for Familial Colorectal Cancer Surveillance

By Will Boggs MD

November 11, 2015

NEW YORK (Reuters Health) - Surveillance colonoscopy every six years is "appropriate" for individuals at risk for familial colorectal cancer, researchers from the Netherlands report.

"Individuals with one first-degree relative with colorectal cancer (CRC) <50 years old or two first-degree relatives with CRC independent of age at diagnosis have a moderately increased risk of developing CRC and are referred to as familial CRC," Dr. Hans F. A. Vasen, from Leiden University Medical Center, told Reuters Health by email. "In such cases, colonoscopy at intervals of six years is safe."

The optimal surveillance interval for these individuals has not been determined, and current guidelines recommend surveillance at intervals varying from three to five to six years, starting from the age of 45 years.

Dr. Vasen and colleagues in the Familial CRC Surveillance (FACTS) trial compared the rates of advanced adenomatous polyps (AAPs) in a nationwide study of patients with familial CRC who were randomized to follow-up colonoscopic screening at three years (266 individuals) or six years (262 individuals) after an initial colonoscopy that identified zero to two adenomas.

More patients had adenomas at six than at three years (26% vs. 13%; p<0.01), but the difference in AAPs fell short of statistical significance (6.9% vs. 3.5%, p=0.09).

"I had expected a higher frequency of advanced adenomatous polyps than observed in our study," Dr. Vasen said. "The question arises whether the risk in familial CRC is really as high as suggested by the previous studies."

The proportion of patients with adenomas and AAPs was also lower with the second three-year surveillance than with the six-year surveillance, the researchers report in the Journal of Clinical Oncology, online November 2.

An analysis of risk factors identified baseline AAPs as the only variable that independently predicted the development of AAPs by the first follow-up.

Based on the findings, the researchers say, "we consider a 6-year surveillance interval appropriate."

"Future studies should address the upper age limit for surveillance and, in particular, determine the cutoff point at which the advantages of surveillance are outweighed by disadvantages of colonoscopic surveillance," they note.

"If a family is suspected for hereditary colorectal cancer (Lynch syndrome)(for example, CRC <50 years; three or more relatives with CRC; combination with endometrial cancer), the index patient with CRC should have genetic testing to exclude Lynch syndrome for which an intensive screening protocol is recommended (at 1-2 year-intervals)," Dr. Vasen added.

"Because in the present study, there was no evidence for an accelerated carcinogenesis . . . as observed in Lynch syndrome and also because of the relatively low rate of advanced adenomas (7%) observed at 6-year follow-up, it would be an interesting question whether a more relaxed program, for example, colonoscopy at 10 years intervals (or even two yearly fecal blood testing, I-FOBT??) is also safe," Dr. Vasen added. "Future studies should address this question."

Dr. David F. Ransohoff from the University of North Carolina at Chapel Hill, who has studied colorectal cancer screening but was not involved in the new work, told Reuters Health by email, "Six years seems reasonable as a surveillance interval, because the rate of serious outcomes was so low in both groups. The risk of a serious lesion in this increased-risk subgroup (one first-degree relative (FDR) with CRC under age 50, or two FDRs with CRC at any age) is still not very high, and we may do overly-intense surveillance."

"It's not clear from this study when the 'next' surveillance should be done, but an additional 6 years might be very reasonable, especially if no serious lesions were found at the first surveillance exam," Dr. Ransohoff said. "Further 'stretching out' of the interval might also be reasonable if additional surveillance exams show no serious lesions. In other words, the length of later intervals can modified based on what, cumulatively, is found in surveillance."


J Clin Oncol 2015.