Optimizing post-polypectomy surveillance: when less is more

Compared with the general population, patients who undergo removal of colorectal adenomas or serrated polyps are at an increased risk of developing colorectal cancer (CRC) [1]. Therefore, surveillance colonoscopy has been established as a routine clinical practice to prevent the development of this neoplasm.

The strategies for post-polypectomy surveillance in the current guidelines are based on the risk of each patient according to the number, size, and histopathological findings of polyps at baseline colonoscopy. Overall, the primary outcome has been the detection of metachronous advanced adenoma as a surrogate marker for CRC, and the recommendations for surveillance intervals rely on results from observational studies performed in the 1980 s and 1990 s. In fact, randomized controlled trials (RCTs) investigating the impact of surveillance intervals on the incidence of CRC as the primary end point are lacking. That is probably a major reason for the discrepancies between the current guidelines with regard to the stratification of patient risk and surveillance recommendations. For low risk patients (those with 1 – 2 adenomas < 10 mm in diameter, without villous histology or high grade dysplasia), US Multi-Society Task Force (USMSTF) guidelines [2] recommend colonoscopy surveillance every 5 – 10 years, whereas European guidelines propose no surveillance and a return to the CRC screening program or colonoscopy every 10 years in regions without organized screening programs [3] [4]. Disagreements between guidelines also involve high risk patients. These patients have been subcategorized in some guidelines [3] as intermediate risk patients (those with 3 – 4 small adenomas, or at least one adenoma of 10 – 20 mm in diameter) for whom a 3-year surveillance interval is recommended, or as highest risk patients (those with ≥ 5 adenomas or at least 1 adenoma ≥ 20 mm in diameter) for whom a 1-year surveillance interval is recommended [3]. In contrast, other guidelines included all patients with high risk lesions in a single group, recommending surveillance colonoscopy every 3 years [4]. Finally, there is universal agreement that a work-up colonoscopy should be performed within 3 – 6 months in patients with incomplete colonoscopies or with piecemeal resection of large polyps at baseline colonoscopy [2] [3] [4].

“The recent evidence suggesting a null impact of surveillance on CRC incidence and mortality in low risk patients should be taken into account in the next update of the guidelines.”

Regardless of the patient’s level of risk, there are two conditions that are of the utmost importance to ensure the optimal effectiveness of post-polypectomy surveillance: first, recommendations should be considered in the setting of a high quality baseline colonoscopy, defined as a complete exploration with cecal intubation, adequate bowel preparation, and complete removal of all detected polyps [5]; second, to minimize the risk of post-colonoscopy CRC, endoscopists should have an adequate (at least 25 %) adenoma detection rate (ADR) [5]. In addition, an acceptable adherence to the guidelines is recommended to avoid overuse or underuse of explorations.

In this issue of Endoscopy, Djinbachian et al. [6] report on a well-conducted meta-analysis providing a global perspective on the adherence to post-polypectomy surveillance guidelines. Although the study has limitations related to high levels of heterogeneity, the authors provide enough high quality evidence to support their conclusions. They found that less than 50 % of patients undergoing surveillance colonoscopy adhered to the guidelines. The majority of non-compliers (42.6 %) had shorter than recommended intervals, whereas a much smaller proportion (7.9 %) had delayed surveillance intervals. A shorter than recommended surveillance interval was observed in 55.3 % of low risk patients and in 17.2 % of high risk patients. Conversely, delayed surveillance was observed in 1.1 % and 15.0 % of the low and high risk groups, respectively. Interestingly, the inappropriate application of surveillance colonoscopy in low risk patients was markedly higher among those following the European guidelines compared with those following the American guidelines [3] [4]. This suggests that physicians are still not confident enough in these guidelines. Most likely, difficulties in confirming that a high quality baseline colonoscopy was performed or disparities regarding the appropriate surveillance intervals between the European and American guidelines may explain the reduced adherence to the European guidelines. However, new knowledge in the field supports the uselessness of surveillance after the removal of small hyperplastic polyps or low risk polyps and following a normal colonoscopy, as these individuals have similar or lower risk of developing CRC than those in the general population [7].

Surveillance colonoscopies account for approximately 25 % of all performed colonoscopies and about 80 % of them are in low risk patients. The current reality is that the extended overuse of surveillance is resulting in a substantial workload in endoscopy units, increasing the overdiagnosis and overtreatment of polyps, without having shown a benefit in the prevention of CRC. This practice might worsen in the coming years, during which the progressive implementation of CRC screening, improvements in colonoscopy quality, and a higher ADR driven by the incorporation of new technologies will result in more detected adenomas, which paradoxically may lead to shorter surveillance intervals. Finally, this endoscopic burden may lead to inequities, with increased waiting times for patients with other indications.

How can we reverse this situation? First, if post-polypectomy surveillance is aimed at preventing CRC, the primary outcome should be the reduction of CRC incidence and mortality, and not the detection of metachronous advanced adenoma, as stated in current guidelines. Adenomas are identified in approximately 50 % of individuals older than 50 years, but only a minority of them will develop CRC. Therefore, the recent evidence suggesting a null impact of surveillance on CRC incidence and mortality [7] in low risk patients should be taken into account in the next update of the guidelines; second, as Djinbachian et al. [6] suggest, new interventions should be implemented to increase guideline adherence, with the aim of minimizing surveillance overuse or underuse. They suggest including appropriate surveillance intervals in a checklist together with other quality metrics. This intervention might improve adherence but will require additional effort on the part of the endoscopist. In particular, written reports that include a reminder of the timing for surveillance to patients and their physicians should be generated through standardized electronic reporting systems that integrate endoscopic and histopathological findings.

Meanwhile, as we wait for the results of the ongoing EpOS trial [8], a large-scale international RCT investigating the optimal surveillance intervals after polypectomy with regard to CRC incidence, we have to proceed with a more rational approach, balancing the risks and benefits, and considering offering surveillance colonoscopy only to those individuals who are most likely to benefit from it.

• References

• 1 Cottet V, Jooste V, Fournel I. et al. Long-term risk of colorectal cancer after adenoma removal: a population-based cohort study. Gut 2012; 61: 1180-1186
• 2 Lieberman DA, Rex DK, Winawer SJ. et al. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology 2012; 143: 844-857
• 3 von Karsa L, Patnick J. European Colorectal Cancer Screening Guidelines Working Group. et al. European guidelines for quality assurance in colorectal cancer screening and diagnosis: overview and introduction to the full supplement publication. Endoscopy 2013; 45: 51-59
• 4 Hassan C, Quintero E, Dumonceau JM. et al. Post-polypectomy colonoscopy surveillance: European Society of Gastrointestinal Endoscopy (ESGE) Guideline. Endoscopy 2013; 45: 842-851
• 5 Rex DK, Schoenfeld PS, Cohen J. et al. Quality indicators for colonoscopy. Gastrointest Endosc 2015; 81: 31-53
• 6 Djinbachian R, Dubé AJ, Durand M. et al. Adherence to post-polypectomy surveillance guidelines: a systematic review and meta-analysis. Endoscopy 2019; 51: 673-683
• 7 Dube C, Yakubu M, McCurdy BR. et al. Risk of advanced adenoma, colorectal cancer, and colorectal cancer mortality in people with low-risk adenomas at baseline colonoscopy: a systematic review and meta-analysis. Am J Gastroenterol 2017; 112: 1790-1801
• 8 Jover R, Bretthauer M, Dekker E. et al. Rationale and design of the European Polyp Surveillance (EPoS) trials. Endoscopy 2016; 48: 571-578