Endoscopic characterization of sessile serrated adenomas/polyps with and without dysplasia.

BACKGROUND AND STUDY AIMS: Sessile serrated adenomas/polyps (SSA/Ps) are precursors of colorectal cancer (CRC), but their endoscopic detection can be difficult. We therefore examined the endoscopic characteristics of SSA/Ps with and without dysplasia in a cross-sectional study. PATIENTS AND METHODS: We reviewed clinical, endoscopic, and histopathologic data from patients undergoing colonoscopy between February 2008 and February 2012. We categorized colorectal polyps according to anatomic site, size, and shape, and classified serrated polyps using the World Health Organization (WHO) classification. Multiple logistic regression analyses examined potential differences regarding site, size, and shape between SSA/Ps and colorectal adenomas (overall and advanced only). RESULTS: We examined 7433 patients (mean age 59 years, 45.9 % men) with 5968 colorectal polyps. In total, we found 170 SSA/Ps (170/5968, 2.9 %), including 63 SSA/Ps with dysplasia (1.1 %) and 107 SSA/Ps without dysplasia (1.8 %). Compared with SSA/Ps with dysplasia, SSA/Ps without dysplasia were more often proximally located (odds ratio [OR] 3.3, 95 % confidence interval [95 %CI] 1.7 - 6.4), but less often < 6 mm in size (OR 0.6, 95 %CI 0.3 - 1.1). No significant differences were found regarding location between SSA/Ps with dysplasia and advanced adenomas (proximal colon, 47.6 % vs. 40.1 %). However, SSA/Ps with dysplasia were more often < 6 mm in size than advanced adenomas (OR 0.3, 95 %CI 0.2 - 0.5). Of the 63 dysplastic SSA/Ps, 6 (9.5 %) contained high grade dysplasia, but none invasive carcinoma. CONCLUSIONS: SSA/Ps with dysplasia are frequently < 6 mm in size, located throughout the colon and 9.5 % of them contain high grade dysplasia. These findings underscore the importance of high quality colonoscopic examination to maximize protection against CRC.

Postcolonoscopy colorectal cancers are preventable: a population-based study.

OBJECTIVE: The quality of colonoscopy is key for ensuring protection against colorectal cancer (CRC). We therefore aimed to elucidate the aetiology of postcolonoscopy CRCs (PCCRCs), and especially to identify preventable factors. METHODS: We conducted a population-based study of all patients diagnosed with CRC in South-Limburg from 2001 to 2010 using colonoscopy and histopathology records and data from the Netherlands Cancer Registry. PCCRCs were defined as cancers diagnosed within 5 years after an index colonoscopy. According to location, CRCs were categorised into proximal or distal from the splenic flexure and, according to macroscopic aspect, into flat or protruded. Aetiological factors for PCCRCs were subdivided into procedure-related (missed lesions, inadequate examination/surveillance, incomplete resection) and biology-related (new cancers). RESULTS: We included a total of 5107 patients with CRC, of whom 147 (2.9% of all patients, mean age 72.8 years, 55.1% men) had PCCRCs diagnosed on average 26 months after an index colonoscopy. Logistic regression analysis, adjusted for age and gender, showed that PCCRCs were significantly more often proximally located (OR 3.92, 95% CI 2.71 to 5.69), smaller in size (OR 0.78, 95% CI 0.70 to 0.87) and more often flat (OR 1.70, 95% CI 1.18 to 2.43) than prevalent CRCs. Of the PCCRCs, 57.8% were attributed to missed lesions, 19.8% to inadequate examination/surveillance and 8.8% to incomplete resection, while 13.6% were newly developed cancers. CONCLUSIONS: In our experience, 86.4% of all PCCRCs could be explained by procedural factors, especially missed lesions. Quality improvements in performance of colonoscopy, with special attention to the detection and resection of proximally located flat precursors, have the potential to prevent PCCRCs.

Simple clinical risk score identifies patients with serrated polyps in routine practice.

Large, proximal, or dysplastic (LPD) serrated polyps (SP) need accurate endoscopic recognition and removal as these might progress to colorectal cancer. Herewith, we examined the risk factors for having ≥1 LPD SP. We developed and validated a simple SP risk score as a potential tool for improving their detection. We reviewed clinical, endoscopic, and histologic features of serrated polyps in a study of patients undergoing elective colonoscopy (derivation cohort). A self-administered questionnaire was obtained. We conducted logistic regression analyses to identify independent risk factors for having ≥1 LPD SP and incorporated significant variables into a clinical score. We subsequently tested the performance of the SP score in a validation cohort. We examined 2,244 patients in the derivation and 2,402 patients in the validation cohort; 6.3% and 8.2% had ≥1 LPD SP, respectively. Independent risk factors for LPD SPs were age of more than 50 years [OR 2.2; 95% confidence interval (CI), 1.3-3.8; P = 0.004], personal history of serrated polyps (OR 2.6; 95% CI, 1.3-4.9; P = 0.005), current smoking (OR 2.2; 95% CI, 1.4-3.6; P = 0.001), and nondaily/no aspirin use (OR 1.8; 95% CI, 1.1-3.0; P = 0.016). In the validation cohort, a SP score ≥5 points was associated with a 3.0-fold increased odds for LPD SPs, compared with patients with a score <5 points. In the present study, age of more than 50 years, a personal history of serrated polyps, current smoking, and nondaily/no aspirin use were independent risk factors for having LPD SPs. The SP score might aid the endoscopist in the detection of such lesions.

Optical diagnosis of colorectal polyps using high-definition i-scan: an educational experience.

AIM: To examine performances regarding prediction of polyp histology using high-definition (HD) i-scan in a group of endoscopists with varying levels of experience. METHODS: We used a digital library of HD i-scan still images, comprising twin pictures (surface enhancement and tone enhancement), collected at our university hospital. We defined endoscopic features of adenomatous and non-adenomatous polyps, according to the following parameters: color, surface pattern and vascular pattern. We familiarized the participating endoscopists on optical diagnosis of colorectal polyps using a 20-min didactic training session. All endoscopists were asked to evaluate an image set of 50 colorectal polyps with regard to polyp histology. We classified the diagnoses into high confidence (i.e., cases in which the endoscopist could assign a diagnosis with certainty) and low confidence diagnoses (i.e., cases in which the endoscopist preferred to send the polyp for formal histology). Mean sensitivity, specificity and accuracy per endoscopist/image were computed and differences between groups tested using independent-samples t tests. High vs low confidence diagnoses were compared using the paired-samples t test. RESULTS: Eleven endoscopists without previous experience on optical diagnosis evaluated a total of 550 images (396 adenomatous, 154 non-adenomatous). Mean sensitivity, specificity and accuracy for diagnosing adenomas were 79.3%, 85.7% and 81.1%, respectively. No significant differences were found between gastroenterologists and trainees regarding performances of optical diagnosis (mean accuracy 78.0% vs 82.9%, P = 0.098). Diminutive lesions were predicted with a lower mean accuracy as compared to non-diminutive lesions (74.2% vs 93.1%, P = 0.008). A total of 446 (81.1%) diagnoses were made with high confidence. High confidence diagnoses corresponded to a significantly higher mean accuracy than low confidence diagnoses (84.0% vs 64.3%, P = 0.008). A total of 319 (58.0%) images were evaluated as having excellent quality. Considering excellent quality images in conjunction with high confidence diagnosis, overall accuracy increased to 92.8%. CONCLUSION: After a single training session, endoscopists with varying levels of experience can already provide optical diagnosis with an accuracy of 84.0%.

Endoscopic appearance of proximal colorectal neoplasms and potential implications for colonoscopy in cancer prevention.

BACKGROUND: In everyday practice, the use of colonoscopy for the prevention of colorectal cancer (CRC) is less effective in the proximal than the distal colon. A potential explanation for this is that proximal neoplasms have a more subtle endoscopic appearance, making them more likely to be overlooked. OBJECTIVE: To investigate the differences in endoscopic appearance, ie, diminutive size and nonpolypoid shape, of proximal compared with distal colorectal neoplasms. DESIGN: Cross-sectional, single-center study. SETTING: Endoscopists at the Maastricht University Medical Center in the Netherlands who were previously trained in the detection and classification of nonpolypoid colorectal lesions. PATIENTS: Consecutive patients undergoing elective colonoscopy. MAIN OUTCOME MEASUREMENTS: Endoscopic appearance, ie, diminutive size (<6 mm) or nonpolypoid shape (height less than half of the diameter) of colorectal adenomas and serrated polyps (SPs), with a focus on adenomas with advanced histology, ie, high-grade dysplasia or early CRC and SPs with dysplasia or large size. RESULTS: We included 3720 consecutive patients with 2106 adenomas and 941 SPs. We found that in both men and women, proximal adenomas with high-grade dysplasia/early CRC (n = 181) were more likely to be diminutive or nonpolypoid than distal ones (76.3% vs 26.2%; odds ratio [OR] 9.24; 95% CI, 4.45-19.2; P < .001). Of the proximal adenomas, 84.4% were diminutive or nonpolypoid compared with 68.0% of the distal ones (OR 2.66; 95% CI, 2.14-3.29; P < .001). Likewise, large/dysplastic SPs in the proximal colon were more often nonpolypoid than distal ones (66.2% vs 27.8%; OR 5.51; 95% CI, 2.79-10.9; P < .001). LIMITATIONS: Inclusion of both symptomatic and asymptomatic patients. CONCLUSIONS: Proximal colorectal neoplasms with advanced histology frequently are small or have a nonpolypoid appearance. These findings support careful inspection of the proximal colon, if quality of cancer prevention with the use of colonoscopy is to be optimized.