Serrated and Adenomatous Polyp Detection
Objectives: Detection and removal of adenomas and clinically significant serrated polyps (CSSPs) is critical to the effectiveness of colonoscopy in preventing colorectal cancer. Although longer withdrawal time has been found to increase polyp detection, this association and the use of withdrawal time as a quality indicator remains controversial. Few studies have reported on withdrawal time and serrated polyp detection. Using data from the New Hampshire Colonoscopy Registry, we examined how an endoscopist's withdrawal time in normal colonoscopies affects adenoma and serrated polyp detection.
Methods: We analyzed 7,996 colonoscopies performed in 7,972 patients between 2009 and 2011 by 42 endoscopists at 14 hospitals, ambulatory surgery centers, and community practices. CSSPs were defined as sessile serrated polyps and hyperplastic polyps proximal to the sigmoid. Adenoma and CSSP detection rates were calculated based on median endoscopist withdrawal time in normal exams. Regression models were used to estimate the association of increased normal withdrawal time and polyp, adenoma, and CSSP detection.
Results: Polyp and adenoma detection rates were highest among endoscopists with 9 min median normal withdrawal time, and detection of CSSPs reached its highest levels at 8–9 min. Incident rate ratios for adenoma and CSSP detection increased with each minute of normal withdrawal time above 6 min, with maximum benefit at 9 min for adenomas (1.50, 95% confidence interval (CI) (1.21, 1.85)) and CSSPs (1.77, 95% CI (1.15, 2.72)). When modeling was used to set the minimum withdrawal time at 9 min, we predicted that adenomas and CSSPs would be detected in 302 (3.8%) and 191 (2.4%) more patients. The increase in detection was most striking for the CSSPs, with nearly a 30% relative increase.
Conclusions: A withdrawal time of 9 min resulted in a statistically significant increase in adenoma and serrated polyp detection. Colonoscopy quality may improve with a median normal withdrawal time benchmark of 9 min.
Colorectal cancer (CRC), the second most common cause of cancer deaths in the United States, is one of the few preventable cancers. Polypectomy of adenomatous polyps during colonoscopy has been shown to decrease the incidence of CRC, and the adenoma detection rate (ADR), which indicates the percent of colonoscopies with one or more adenomatous polyps detected, is a primary quality indicator for colonoscopy. Higher ADRs are associated with decreased interval CRC between colonoscopies. Sessile serrated polyps are frequently located in the proximal colon and have been recognized as important precursor lesions for CRC and interval CRC. Improved detection of all precursor lesions is critical to colonoscopy quality and CRC prevention. However, Kahi et al. demonstrated that a significant proportion of proximal serrated polyps may be missed during colonoscopy, and another recent study demonstrated a protective effect for risk of advanced adenomas but not for proximal serrated polyps in patients who had a previous colonoscopy. Thus, identification of strategies to improve polyp detection may be particularly important for serrated lesions.
The polyp detection rate (PDR), the percent of colonoscopies with one or more polyps detected, has been shown to be highly correlated with ADR. Both PDR and ADR vary substantially among endoscopists, potentially undermining the effectiveness of colonoscopy. Similarly, detection of proximal serrated polyps has been shown to be highly variable and endoscopist dependent. Establishment of quality standards to minimize unwarranted variation in performance is a national and international focus, particularly as colonoscopy is the most commonly used CRC screening test in the United States and the only one that allows polypectomy.
Withdrawal time is the time spent examining the colon during withdrawal of the colonoscope from the cecum to the anal canal, the phase during which careful inspection occurs. Endoscopists with longer withdrawal time in colonoscopies with no findings have been found to have higher ADRs, PDRs, and serrated PDRs (SDRs). As evidence supporting this association has accumulated, recommendations for optimal endoscopist mean withdrawal time in normal colonoscopies (NWT) ranging from 6 to 10 min have been suggested. However, significant controversy remains concerning those recommendations as outlined in the comments column of Table 5, and endoscopists face economic pressures to increase efficiency by decreasing colonoscopy procedure time. Additional evidence to assess the strength of the association between longer NWT and increased ADRs and SDRs is needed.
Preliminary analysis in the statewide New Hampshire Colonoscopy Registry (NHCR), examining the relationship between endoscopist median NWT and polyp detection, confirmed the positive relationship between increasing NWT and PDR, ADR, and SDR found by others. In the current analysis, we have used models to allow more detailed examination of the association between NWT and PDR, ADR, and SDR, with the aim of identifying an optimal withdrawal time for maximum adenoma and clinically significant sessile serrated polyp detection. Following guideline recommendations, we defined clinically significant serrated polyps (CSSPs) to be sessile serrated polyps and hyperplastic polyps proximal to the sigmoid. Our a priori hypothesis was that increased NWT would be associated with increases in both adenoma and CSSP detection. Our model incorporated patient and endoscopist characteristics, which may affect both withdrawal time and rates of adenoma and CSSP detection. Finally, we estimated the potential effect on PDR, ADR, and SDR of increasing the minimum NWT in our cohort.
Abstract and Introduction
Abstract
Objectives: Detection and removal of adenomas and clinically significant serrated polyps (CSSPs) is critical to the effectiveness of colonoscopy in preventing colorectal cancer. Although longer withdrawal time has been found to increase polyp detection, this association and the use of withdrawal time as a quality indicator remains controversial. Few studies have reported on withdrawal time and serrated polyp detection. Using data from the New Hampshire Colonoscopy Registry, we examined how an endoscopist's withdrawal time in normal colonoscopies affects adenoma and serrated polyp detection.
Methods: We analyzed 7,996 colonoscopies performed in 7,972 patients between 2009 and 2011 by 42 endoscopists at 14 hospitals, ambulatory surgery centers, and community practices. CSSPs were defined as sessile serrated polyps and hyperplastic polyps proximal to the sigmoid. Adenoma and CSSP detection rates were calculated based on median endoscopist withdrawal time in normal exams. Regression models were used to estimate the association of increased normal withdrawal time and polyp, adenoma, and CSSP detection.
Results: Polyp and adenoma detection rates were highest among endoscopists with 9 min median normal withdrawal time, and detection of CSSPs reached its highest levels at 8–9 min. Incident rate ratios for adenoma and CSSP detection increased with each minute of normal withdrawal time above 6 min, with maximum benefit at 9 min for adenomas (1.50, 95% confidence interval (CI) (1.21, 1.85)) and CSSPs (1.77, 95% CI (1.15, 2.72)). When modeling was used to set the minimum withdrawal time at 9 min, we predicted that adenomas and CSSPs would be detected in 302 (3.8%) and 191 (2.4%) more patients. The increase in detection was most striking for the CSSPs, with nearly a 30% relative increase.
Conclusions: A withdrawal time of 9 min resulted in a statistically significant increase in adenoma and serrated polyp detection. Colonoscopy quality may improve with a median normal withdrawal time benchmark of 9 min.
Introduction
Colorectal cancer (CRC), the second most common cause of cancer deaths in the United States, is one of the few preventable cancers. Polypectomy of adenomatous polyps during colonoscopy has been shown to decrease the incidence of CRC, and the adenoma detection rate (ADR), which indicates the percent of colonoscopies with one or more adenomatous polyps detected, is a primary quality indicator for colonoscopy. Higher ADRs are associated with decreased interval CRC between colonoscopies. Sessile serrated polyps are frequently located in the proximal colon and have been recognized as important precursor lesions for CRC and interval CRC. Improved detection of all precursor lesions is critical to colonoscopy quality and CRC prevention. However, Kahi et al. demonstrated that a significant proportion of proximal serrated polyps may be missed during colonoscopy, and another recent study demonstrated a protective effect for risk of advanced adenomas but not for proximal serrated polyps in patients who had a previous colonoscopy. Thus, identification of strategies to improve polyp detection may be particularly important for serrated lesions.
The polyp detection rate (PDR), the percent of colonoscopies with one or more polyps detected, has been shown to be highly correlated with ADR. Both PDR and ADR vary substantially among endoscopists, potentially undermining the effectiveness of colonoscopy. Similarly, detection of proximal serrated polyps has been shown to be highly variable and endoscopist dependent. Establishment of quality standards to minimize unwarranted variation in performance is a national and international focus, particularly as colonoscopy is the most commonly used CRC screening test in the United States and the only one that allows polypectomy.
Withdrawal time is the time spent examining the colon during withdrawal of the colonoscope from the cecum to the anal canal, the phase during which careful inspection occurs. Endoscopists with longer withdrawal time in colonoscopies with no findings have been found to have higher ADRs, PDRs, and serrated PDRs (SDRs). As evidence supporting this association has accumulated, recommendations for optimal endoscopist mean withdrawal time in normal colonoscopies (NWT) ranging from 6 to 10 min have been suggested. However, significant controversy remains concerning those recommendations as outlined in the comments column of Table 5, and endoscopists face economic pressures to increase efficiency by decreasing colonoscopy procedure time. Additional evidence to assess the strength of the association between longer NWT and increased ADRs and SDRs is needed.
Preliminary analysis in the statewide New Hampshire Colonoscopy Registry (NHCR), examining the relationship between endoscopist median NWT and polyp detection, confirmed the positive relationship between increasing NWT and PDR, ADR, and SDR found by others. In the current analysis, we have used models to allow more detailed examination of the association between NWT and PDR, ADR, and SDR, with the aim of identifying an optimal withdrawal time for maximum adenoma and clinically significant sessile serrated polyp detection. Following guideline recommendations, we defined clinically significant serrated polyps (CSSPs) to be sessile serrated polyps and hyperplastic polyps proximal to the sigmoid. Our a priori hypothesis was that increased NWT would be associated with increases in both adenoma and CSSP detection. Our model incorporated patient and endoscopist characteristics, which may affect both withdrawal time and rates of adenoma and CSSP detection. Finally, we estimated the potential effect on PDR, ADR, and SDR of increasing the minimum NWT in our cohort.
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