Assessment of the multiple components of the variability in the adenoma detection rate in sigmoidoscopy screening, and lessons for training

Gastroenterology Unit, Mauriziano Umberto I Hospital, Turin, Italy.
Endoscopy (Impact Factor: 5.2). 04/2010; 42(6):448-55. DOI: 10.1055/s-0029-1244131
Source: PubMed

ABSTRACT The determinants of the observed variability of adenoma detection rate (ADR) in endoscopy screening have not yet been fully explained.
Between November 1999 and November 2006 13 764 people (7094 men, 6670 women; age range 55-64) underwent screening flexible sigmoidoscopy at five hospital endoscopy units in Turin. To study the determinants of the ADR for distal adenomas, accounting for patient, examiner, and hospital characteristics, we applied a multivariate multilevel regression model.
Average ADRs for all adenomas and for advanced adenomas (size > or = 10 mm, villous component > 20 %, high grade dysplasia) were 13.5 % (range 5.2 %-25.0 %) and 6.4 % (3.1 %-10.7 %) for men, and 8.0 % (2.5 %-14.0 %) and 3.7 % (0.2 % - 7.4 %) for women. In multivariate analysis, increased ADR of advanced adenomas was associated with male gender (odds ratio [OR] 1.78, 95 %CI 1.49 - 2.11), self-report of one first-degree relative with colorectal cancer (CRC) (1.44, 1.11-1.86), or of recent-onset rectal bleeding (1.73, 1.24-2.40). Adjusting for these variables, a significantly lower ADR was found for endoscopists with either a lower rate of incomplete sigmoidoscopy (< 9 %; OR 0.59, 95 %CI 0.41-0.87) or a higher rate (> 12 %; 0.64, 0.45-0.91), or with low activity volume (< 85 sigmoidoscopies/year; 0.66, 0.50-0.86). Residual variability explained by the endoscopy center effect was about 1 % and statistically significant.
Endoscopist performance in flexible sigmoidoscopy CRC screening is highly variable. Low volume of screening activity independently predicts lower ADR, suggesting that operators devoting more time to screening sigmoidoscopy may perform better. Variability among pathologists in adenoma classification might explain part of the residual variability across endoscopy units.

1 Bookmark
  • [Show abstract] [Hide abstract]
    ABSTRACT: In 1992, two well-conducted case-control studies used data from two different health maintenance organizations and demonstrated a 59-79% reduction in mortality from colorectal cancer (CRC) following exposure to sigmoidoscopy. These studies highlight the possibility of reducing mortality from CRC using population-based endoscopic screening. The development of fiber optics improved the technology, and the ease of performing flexible sigmoidoscopy (FS) with widespread adoption of this screening modality. To date, FS is the only endoscopic screening modality that has been shown to reduce mortality in randomized clinical trials. This article reviews the development of sigmoidoscopy, its use in CRC screening and the current reduced role of this proven screening modality, and explores new frontiers for population-based FS screening.
    Clinical Colorectal Cancer 08/2012; 1(4):309-319. DOI:10.2217/crc.12.33 · 2.91 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The past few years have seen a shift in focus for endoscopy research. For example, there has been a halt in the apparent revolution of natural orifice transluminal surgery (NOTES), which was long considered the most important innovation in flexible endoscopy. Other trends such as endoscopic histology are slowing down and not progressing into clinical practice. In general, the quality of endoscopic research needs to be improved, particularly in the field of diagnostics and imaging 1. Nevertheless, progress in some areas continues, albeit at a slower pace than we might like. In this review the areas of current interest are reviewed with reference to the most relevant areas of progress in recent years.
    Endoscopy 12/2012; 44(12):1148-57. DOI:10.1055/s-0032-1325994 · 5.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Colorectal cancer is a significant cause of death. Removal of precancerous adenomas, and early detection and treatment of cancer, has been shown to reduce the risk of death. The aim of this review and meta-analysis was to determine whether flexible sigmoidoscopy (FS) is an effective population screening method for reducing mortality from colorectal cancer. Methods: MEDLINE (1946 to December 2012) and Embase (1980-2012, week 15) were searched for randomized clinical trials in which FS was used to screen non-symptomatic adults from a general population, and FS was compared with either no screening or any other alternative screening methods. Meta-analysis was carried out using a random-effects Mantel-Haenzsel model. Results: Twenty-four papers met the inclusion criteria, reporting results from 14 trials. Uptake of FS was usually lower than that for stool-based tests, although FS was more effective at detecting advanced adenoma and carcinoma. FS reduced the incidence of colorectal cancer after screening, and long-term mortality from colorectal cancer, compared with no screening in a selected population. Compared with stool-based tests in a general population, FS was associated with fewer interval cancers. Conclusion: FS is efficacious at reducing colorectal cancer mortality compared with no screening. It is more effective at detecting advanced adenoma and carcinoma than stool-based tests. FS may be compromised by poorer uptake. Introduction of FS as a screening method should be done on a pilot basis in populations in which it is not currently used, and close attention should be paid to maximizing uptake. The relative risk of adverse events with FS compared with stool-based tests should be quantified, and its real-world effectiveness evaluated against the most effective stool-based tests.
    British Journal of Surgery 11/2012; 99(11):1490 - 1502. DOI:10.1002/bjs.8882 · 4.84 Impact Factor