medwireNews: We cover three studies of colorectal cancer (CRC) surveillance, one evaluating the relationship between adenomas at colonoscopy and the long-term incidence of cancer, while the other two investigate whether higher-intensity post-surgery follow-up improves outcomes.
All three research articles and an accompanying editorial are published in JAMA.
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Individuals with advanced adenomas (≥1 cm, high-grade dysplasia, or tubulovillous or villous histology) on a diagnostic colonoscopy have a significant 2.7-fold increased risk for developing CRC relative to those with no adenomas, but the risk is not elevated for those with non-advanced adenomas (<1 cm without advanced histology), report Robert Schoen (University of Pittsburgh, Pennsylvania, USA) and co-investigators.
They followed up – for a median of 12.9 years – 15,935 participants of the PLCO trial who underwent colonoscopy after a positive flexible sigmoidoscopy result.
Schoen et al say that “these findings support periodic, ongoing surveillance colonoscopy” in patients with advanced adenomas, but could lead to a longer surveillance interval for those with non-advanced adenomas, provided the results are replicated in appropriately powered trials.
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The intensity of surveillance after curative surgery for early-stage CRC is not significantly associated with outcomes, indicate the findings of two studies.
In the COLOFOL trial, 2509 patients with stage II–III CRC were randomly assigned to undergo postoperative follow-up with computed tomography and serum carcinoembryonic antigen (CEA) testing either at high (at 6, 12, 18, 24, and 36 months) or low (at 12 and 36 months) intensity.
As reported by Henrik Sørensen, from Aarhus University Hospital in Denmark, and team, the 5-year overall and CRC-specific mortality rates did not differ significantly between groups, at 13.0% versus 14.1% and 10.6% versus 11.4%, respectively.
These results “should be considered as the evidence base” for updating the National Comprehensive Cancer Network and the American Society of Clinical Oncology guidelines, they conclude.
George Chang (The University of Texas MD Anderson Cancer Center, Houston, USA) and co-authors arrived at a similar conclusion following their analysis of records on 8529 stage I–III CRC patients included in the Commission on Cancer Special Study and the US National Cancer Database.
There was no difference in the median time to detection of recurrence, cancer recurrence resection rates, and overall survival between patients who underwent imaging or CEA testing at facilities classed as high-intensity or low-intensity, evaluated empirically on the basis of the observed-to-expected testing ratio.
Commenting on the studies, Hanna Sanoff (University of North Carolina at Chapel Hill, USA) says that “[c]urrent guidelines should be reevaluated” in light of these data and “the potential harms of more frequent testing including distress, radiation exposure, and patient and societal financial burden.”
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