These results raise issues about the quality of post-polypectomy surveillance regarding the appropriateness of endoscopists’ recommendations, quality of bowel prep, and quality of reporting. Physicians’ recommendations for post-polypectomy surveillance are somewhat aggressive for low-risk hyperplastic and small or medium adenomas, even single small adenomas less than 0.5 cm in size; such lesions are important because they make up such a large portion of colonoscopy findings. Bowel prep that is less than excellent may affect recommendations, because such persons tended to have shorter surveillance intervals for low-risk lesions. This finding might be particularly important because only 17.5% of bowel preps were considered excellent. The lack a statistically significant difference for prep quality on “all findings” for hyperplastic polyps or for single small adenoma might be a result of small sample sizes and large errors (design effect) for testing because of the clustered nature of the data. Similarly, the finding of no statistically significant difference based on prep quality for persons with high-risk adenoma might be because the surveillance interval was already aggressive for that category. Last, quality of reporting was an issue in that 32.1% of persons had no data reported about bowel prep, and in most cases it was unclear whether a recommendation was made before or after pathology had been reported back to the physician.
Are Physicians’ Recommendations Becoming More Aggressive Over Time?
The intensity of post-polypectomy surveillance for small lesions may be increasing over time. A recent report of surveillance behavior around the year 2000 was based on a study in which persons discovered to have polyps before January 2000 were asked, after an interval of 5 years or longer had passed (e.g. in 2005 or later), whether follow-up surveillance colonoscopy had been done [18
]. The current study, describing behavior around 2003 and based on review of in-office records, shows more-aggressive follow-up, although one of several guidelines had changed around that time.
Comparing Physicians’ Recommendations with Guidelines
Follow-up recommendations must be interpreted in the light of guidelines for post-polypectomy surveillance that may disagree with one another at any one point in time and that may vary over time, sometimes making it difficult to understand which guidelines are “in effect.”
Despite some variation, however, virtually all recommending organizations have agreed that small hyperplastic polyps confer no increased future risk of CRC and so require no increased follow-up. Thus the practice described in this study may be seen as somewhat aggressive compared with those guidelines. Our category “hyperplastic polyps” (i.e. small size, small number, and in the left colon only) was intended to comprise only those persons that all observers would agree are at “low risk.”
For small adenomas, however, guidelines have sometimes disagreed with one another at any one point in time. While the initial polyp guidelines [22
] recommended no special follow-up for persons with one small adenoma, beyond the “routine” 10-year interval for persons with average risk (), in 1997 guidelines started to become more aggressive, with several organizations then recommending follow-up after 5 years for a single small adenoma. After 1997, only one major organization, the American Cancer Society in 2001, recommended a moreintense follow-up interval (3–6 years). That ACS recommendation was, then, “in effect” during the time of this study as were the 5-year recommendations of both the American College of Gastroenterology and the American Society for Gastrointestinal Endoscopy (). Then, in 2006 and 2008, the guidelines of several organizations, including the American Cancer Society [15
], reverted back to a longer surveillance period, noting that “follow-up intervals … have been lengthened,” becoming more similar to earlier guidelines [23
]. The current study’s results, showing that for 35% of persons with small adenomas follow-up by three years was recommended, would be considered “overly-aggressive” by two of the guidelines but technically “within guidelines”—though at the aggressive end—of the ACS at that time.
Guidelines for post-polypectomy surveillance
Determinants of Physician Behavior
While this study suggests that physicians may behave at the aggressive end of guidelines recommendations, specific determinants for this behavior are not understood [24
]. Physicians might disagree with guidelines or not trust them [25
], or be unfamiliar with them, or they might consider other factors in making decisions, for example suboptimum colon prep, or patient preference or worry, or potential legal liability of “missed cancers.” Pressures to be aggressive in diagnosis and treatment have been described for other cancers [26
Recommendations about post-polypectomy surveillance, particularly for small adenomatous polyps, may have substantial implications for clinical practice, because approximately 90% of all adenomas are under 1 cm, and approximately half of persons with adenoma have a single small adenoma. Although recent recommendations for follow-up of small adenomas have become less aggressive, recent reports about the potential importance of “flat lesions” [27
], missed lesions [28
], and concern about “quality” of examination and polyp-detection rates [30
] might cause physicians to be more aggressive both in finding very small adenomas, and in making surveillance recommendations. The use of high-resolution colonoscopes may result in more frequent discovery of very small adenomas whose natural history is not known.
Deciding appropriate intervals for post-polypectomy surveillance requires consideration of evidence about the future risk of CRC after polypectomy. Such data are hard to obtain because of the need to follow people who have had polyps removed but do not have periodic surveillance colonoscopy. Such natural history data will be provided in the recent UK clinical trial of sigmoidoscopy screening, at least for persons who had small adenomas in the left colon [31
]. In that study, persons with one or two small adenomas (defined as under 1 cm) were considered to be in a “low-risk group” (with persons with no polyps found by sigmoidoscopy) that did not receive either an initial colonoscopic workup or post-polypectomy colonoscopic surveillance. In 10 years of follow-up, the “low-risk” group had a CRC incidence of only 0.02–0.04% per year, suggesting that having one or two small adenomas (in the left colon) is not associated with a high future CRC risk in the left colon. Whether such results apply to the right colon is not known. In the meantime, the perhaps unexpected low incidence of CRC after polypectomy in this RCT highlights the importance of obtaining empirical data about future risk of CRC among persons who have had adenomas, and it suggests that there may be no connection between what many persons currently believe (high future risk of CRC for anyone with an adenoma, requiring aggressive surveillance) and what cohort data may eventually show.
Limitations of this study include the low participation. On the one hand, we were surprised and gratified that so many physicians did participate, considering that the study involved on-site auditing of patient records. On the other hand, we do not know whether physicians who did not participate would have had the same frequency distribution of recommendations compared to those who participated. Another limitation is that we relied totally on the patient medical record in the practice for information, and information in the medical record was not always complete. However, we did not classify a lesion without data being present and only used recommendations that were noted. If data are more likely to be missing when the recommendation was more aggressive, that could bias our results, but we doubt this to be the case. Also we were not able to identify possible “predictors” of different surveillance behavior (for example, such patient features as race, gender, or insurance status; or features of physicians or of practices), using bivariate and multivariate analyses, because data were not collected or were not available uniformly in charts. Although we think such details may be interesting, we believe that the “bigger picture” behavior, documented in this study by examination of in-practice medical records, is of primary importance. Another limitation is that geographic area is limited to one state. Last, it is possible that practice has changed since the time of this study, and this study’s results can be assessed only in light of the recommendations that were “in effect” at the time of the study.
In conclusion, these results highlight issues of quality in post-polypectomy surveillance. First, there is disparity between physician recommendations and guidelines, such that many patients with low-risk polyps are advised to have surveillance at shorter intervals than suggested by evidence and guidelines, thus exposing patients to unnecessary risk and cost. Second, there are problems in endoscopic reporting if bowel prep quality is not described in nearly one-third of reports, making it difficult to determine the thoroughness of an exam. Future research should explore reasons for physicians’ decisions and the possible disparity between recommendations and guidelines, and these findings should be considered in developing quality-improvement initiatives for post-polypectomy surveillance.