Baseline Screening Colonoscopy Research Articles

Colorectal Cancer After Screening Colonoscopy: 10-Year Incidence by Site and Detection Rate at First Repeat Colonoscopy.

We aimed to describe cumulative colorectal cancer (CRC) incidence after screening colonoscopy stratified by tumor location, age, and sex as well as CRC detection rate at first repeat colonoscopy. Using the German Pharmacoepidemiological Research Database, we included persons with screening colonoscopy and assessed cumulative CRC incidence after baseline screening colonoscopy with snare polypectomy (cohort 1) and without polypectomy (cohort 2). We also determined the CRC detection rate at first repeat colonoscopy by time since screening colonoscopy. Overall, 1,095,381 persons were included. The 10-year cumulative CRC incidence was 1.5% in cohort 1 and 0.6% in cohort 2. The proportion of proximal CRC increased with age: In women of cohort 1, 47% of CRCs in the age group 55-64 years were proximal (men: 42%) while in the age group 65-74 years, this proportion was 55% (men: 49%). In cohort 2, similar patterns were observed. In cohort 1, the CRC detection rate at first repeat colonoscopy among persons examined within 6-8 years after screening colonoscopy was more than twice as high compared with those examined within 4-6 years (1.7% vs 0.8%). Among persons followed up after screening colonoscopy, we observed a steadily increasing predominance of proximal CRC, and this shift showed distinct patterns by age and sex. Because our study suggests higher CRC detection rates among persons with a later repeat colonoscopy, the role of delayed surveillance and the benefit of a reminder system should be explored.

Optimal Colonoscopic Surveillance Interval After Normal Baseline Screening Colonoscopy.

The optimal colonoscopic surveillance interval in the Chinese population is unclear. The present study aimed to assess the optimal colonoscopic surveillance interval after normal baseline screening colonoscopy to avoid overuse or underuse of colonoscopy. This retrospective study included individuals with normal baseline colonoscopy who had undergone at least 2 follow-up colonoscopy examinations at the Digestive Endoscopy Center of our hospital between 2000 and 2013. The risk factors for adenoma and the optimal colonoscopic surveillance interval were assessed. A total of 1,005 individuals (419 men; mean age, 49.34 ± 13.29 years) were included in the study. Of these, 169 individuals had adenomas at colonoscopic surveillance (mean, 1.32 ± 0.79 procedures). The mean adenoma diameter was 0.54 ± 0.38 cm, and the mean number of adenomas was 1.76 ± 1.29. The mean adenoma surveillance interval was 4.76 ± 2.89 years. The risk factors for adenoma identification were age more than 50 years and male gender. The optimal colonoscopic surveillance interval was 4.76 years according to an adenoma detection rate of 5%. The optimal colonoscopic surveillance interval is around 5 years for individuals with normal baseline colonoscopy. Age more than 50 years and male gender are risk factors for adenoma identification.

Advanced neoplasia in Veterans at screening colonoscopy using the National Cancer Institute Risk Assessment Tool

BackgroundAdapting screening strategy to colorectal cancer (CRC) risk may improve efficiency for all stakeholders however limited tools for such risk stratification exist. Colorectal cancers usually evolve from advanced neoplasms that are present for years. We applied the National Cancer Institute (NCI) CRC Risk Assessment Tool, which calculates future risk of CRC, to determine whether it could be used to predict current advanced neoplasia (AN) in a veteran cohort undergoing a baseline screening colonoscopy.MethodsThis was a prospective assessment of the relationship between future CRC risk predicted by the NCI tool, and the presence of AN at screening colonoscopy. Family, medical, dietary and physical activity histories were collected at the time of screening colonoscopy and used to calculate absolute CRC risk at 5, 10 and 20 years. Discriminatory accuracy was assessed.ResultsOf 3121 veterans undergoing screening colonoscopy, 94% had complete data available to calculate risk (N = 2934, median age 63 years, 100% men, and 15% minorities). Prevalence of AN at baseline screening colonoscopy was 11 % (N = 313). For tertiles of estimated absolute CRC risk at 5 years, AN prevalences were 6.54% (95% CI, 4.99, 8.09), 11.26% (95% CI, 9.28-13.24), and 14.21% (95% CI, 12.02-16.40). For tertiles of estimated risk at 10 years, the prevalences were 6.34% (95% CI, 4.81-7.87), 11.25% (95% CI, 9.27-13.23), and 14.42% (95% CI, 12.22-16.62). For tertiles of estimated absolute CRC risk at 20 years, current AN prevalences were 7.54% (95% CI, 5.75-9.33), 10.53% (95% CI, 8.45-12.61), and 12.44% (95% CI, 10.2-14.68). The area under the curve for predicting current AN was 0.60 (95% CI; 0.57-0.63, p < 0.0001) at 5 years, 0.60 (95% CI, 0.57-0.63, p < 0.0001) at 10 years and 0.58 (95% CI, 0.54-0.61, p < 0.0001) at 20 years.ConclusionThe NCI tool had modest discriminatory function for estimating the presence of current advanced neoplasia in veterans undergoing a first screening colonoscopy. These findings are comparable to other clinically utilized cancer risk prediction models and may be used to inform the benefit-risk assessment of screening, particularly for patients with competing comorbidities and lower risk, for whom a non-invasive screening approach is preferred.

Does Colon Polyp Surveillance Improve Patient Outcomes?

Colon polyp surveillance now accounts for 25% of all colonoscopies performed. The evidence that colonoscopy surveillance reduces colorectal cancer (CRC) incidence or mortality is weak. The biology of the baseline lesions and quality of the baseline exam are two primary factors contributing to post-colonoscopy CRC. Prior recommendations for surveillance were based largely on the likelihood that patients with adenomas would develop advanced adenomas, a surrogate for CRC. There is now evidence that baseline colonoscopy findings are strongly associated with the risk of incidence or death from CRC. This evidence provides a basis for updated evidence-based recommendations for surveillance. In addition, there is also growing evidence that the quality of the baseline exam is an important predictor of the likelihood of developing post-colonoscopy CRC.

1677 Few Bumps in the Road Led to Surgical Prophylaxis: Cowden’s Syndrome

INTRODUCTION: PTEN syndrome is caused by a germline mutation in phosphatase and tensin homolog (PTEN) gene. As a syndrome, it has different clinical manifestations, Cowden syndrome being one of them. We present the case of a 41-year-old female found to have multiple polyps throughout the large and small bowel. Biopsy showed hamartomous type polyps and ganglioneuromas. Genetic testing revealed de novo PTEN mutation. CASE DESCRIPTION/METHODS: 41-year-old female presented with acute diarrhea to the emergency department. Medical history was relevant for hypothyroidism secondary to thyroidectomy for goiter and multiple skin tags. Colonoscopy showed the small and large bowel carpeted with polyps and biopsies were taken. Pathology showed hamartomatous-type polyps and ganglioneuromas. Genetic testing was positive for PTEN de novo mutation. A multidisciplinary team was involved in the case for cancer surveillance. Estrogen/progesterone receptor positive and HER2-negative invasive lobular carcinoma was found after bilateral prophylactic mastectomy. Follow up endoscopy showed small esophageal nodules and multiple gastroduodenal polyps found to be hyperplastic on pathology. Hysterectomy is planned with subsequent Arimidex as adjuvant therapy. DISCUSSION: First reported in 1963, Cowden syndrome has a prevalence of 1 in 200,000–250,000 with 20–34% of individuals having germline PTEN mutation. PTEN acts as a tumor suppressor. A mutation of this gene leads to an increased prevelance of a variety of malignancies (colorectal, breast, thyroid, renal, endometrial skin, and brain) and non-neoplastic growths (trichilemmoma, papules, acral keratosis). The purpose of bringing attention to this very rare polyposis syndrome is increase awareness about the multidisciplinary approach needed for cancer surveillance. Annual physical exam should be performed starting at age 18; baseline screening colonoscopy at age 35 with follow up screening earlier than 5 years. Annual urinalysis and cytology to screen for renal cancer is recommended to start at age 35. Surveillance for thyroid cancer includes baseline thyroid ultrasound starting at age 18, and then annual thyroid exams thereafter. Women with PTEN mutations should have annual breast cancer screening starting at age 25. Our patient was advised to undergo appropriate cancer surveillance according to the National Cancer Center Network guidelines.

Baseline Colonoscopy Findings Associated With 10-Year Outcomes in a Screening Cohort Undergoing Colonoscopy Surveillance

Few studies have evaluated long-term outcomes of ongoing colonoscopic screening and surveillance in a screening population. We aimed to determine the 10-year risk for advanced neoplasia (defined as adenomas ≥10mm, adenomas with villous histology or high-grade dysplasia, or colorectal cancer [CRC]) and assessed whether baseline colonoscopy findings were associated with long-term outcomes. We collected data from the Department of Veterans Affairs Cooperative Studies Program Study on 3121 asymptomatic veterans (50-75 years old) who underwent a screening colonoscopy from 1994 through 1997 at 13 medical centers and were then followed for 10 years or until death. We included 1915 subjects with at least 1 surveillance colonoscopy and estimated cumulative incidence of advanced neoplasia by Kaplan-Meier curves. We then fit a longitudinal joint model to estimate risk of advanced neoplasia at each subsequent examination after baseline, adjusting for multiple colonoscopies within individuals. Through 10 years of follow-up, there were 146 individuals among all baseline colonoscopy groups found to have at least 1 incident advanced neoplasia. The cumulative 10-year incidence of advanced neoplasia was highest among those with baseline CRC (43.7%; 95% CI 13.0%-74.4%), followed by those with baseline advanced adenoma (AA) (21.9%; 95% CI 15.7-28.1). The cumulative 10-year incidence of advanced neoplasia was 6.3% (95% CI 4.1%-8.5%) and 4.1% (95% CI 2.7%-5.4%) for baseline 1 to 2 small adenomas (<1cm, and without villous histology or high-grade dysplasia) and no neoplasia, respectively (log-rank P= .10). After adjusting for prior surveillance, the risk of advanced neoplasia at each subsequent examination was not significantly increased in veterans with 1 or 2 small adenomas at baseline (odds ratio 0.96; 95% CI 0.67-1.41) compared with veterans with no baseline neoplasia. Baseline screening colonoscopy findings associate with advanced neoplasia within 10 years. Individuals with only 1 or 2 small adenomas at baseline have a low risk of advanced neoplasia over 10 years. Alternative surveillance strategies, could be considered for these individuals.

Validation of the NCI Colorectal Cancer Risk Assessment Tool for baseline advanced neoplasia in a veterans cohort.

521 Background: Tailoring screening strategy to colorectal cancer (CRC) risk may improve efficiency for all stakeholders. We applied the National Cancer Institute (NCI) CRC Risk Assessment Tool, which calculates 5-10-year, and 20-year absolute risk of colorectal cancer to determine whether it could be used to predict baseline risk of colorectal cancer precursors in a Veterans cohort undergoing first screening colonoscopy. Methods: This was a prospective evaluation of whether the NCI CRC Risk Assessment Tool which offers an absolute risk over time, could be used to estimate baseline cancerous precursors (advanced neoplasia) in Veterans undergoing first screening colonoscopy. Family, medical, dietary and physical activity histories were collected at the time of screening colonoscopy and used to calculate absolute 5, 10, and 20-year CRC risk, and to compare estimated CRC risk to observed AN. Sensitivity analyses were performed. Results: Of 3,121 Veterans undergoing screening colonoscopy, 94% had complete data available to calculate risk (N = 2,934, median age 63 years, 100% men, and 15% minorities). 11% (N = 313) were diagnosed with AN on baseline screening colonoscopy. The area under the curve for predicting AN was 0.60 (95% CI; 0.57-0.63, p &lt; 0.0001) at 5 years, 0.60 (95% CI, 0.57-0.63, p &lt; 0.0001) at 10 years and 0.58 (95% CI, 0.54-0.61, p &lt; 0.0001) at 20 years. At 5 years, we calculated the sensitivity (0.18, 95% CI; 0.14-0.22), specificity (0.91, 95% CI; 0.90-0.92) positive predictive value (0.19, 95% CI; 0.15-0.24) and negative predictive value (0.90, 95% CI; 0.89-0.91) considering the top 10th percentile of risk tool scores as a positive result. Conclusions: The NCI CRC Risk Assessment Tool had modest discriminatory function for predicting AN risk at 5, 10 and 20 years. The Tool’s specificity and negative predictive value were quite good, highlighting its usefulness in risk prediction. This tool may beused to inform the benefit-risk assessment of screening colonoscopy for patients with competing comorbidities.

Yield of a second screening colonoscopy 10 years after an initialnegative examination in average-risk individuals.

Current guidelines recommend screening colonoscopy at 10-year intervals in average-risk individuals who had baseline screening colonoscopy (no polyps or only hyperplastic polyps≤5mm in the recto-sigmoid colon), but the yield of repeat screening at 10 years is unknown. Our aim was to describe the yield of second screening colonoscopy in average-risk individuals performed at least 8 years after a first screening colonoscopy had shown no polyps or only distal hyperplastic polyps≤5mm in size. This was a review of a database for colonoscopies performed at Indiana University Hospital between January 1999 and November2015. A total of 4463 individuals underwent screening colonoscopy between January 1999 and July 2007, of which 1566 individuals had no polyps, and 334 individuals had only distal hyperplastic polyps≤5mm; 378 individuals (58.4% female) had follow-up screening at least 8 years after the baseline screening examination, with a mean (± standard deviation [SD]) interval of 9.74 years (± 1.2 years; range 8-15 years). Mean (± SD) age at baseline screening examination was 56.7 years (± 5.5 years) and at follow-up screening examination was 66.4 years (±5.6 years). At the second screening, there were 224 patients (59.3%) with at least 1 polyp, including 144(38.1%) with at least 1 conventional adenoma. The adenoma detection rate at the second screening examination was 36.1% and 56.8% in the groups with no polyp at baseline and with only distal hyperplastic polyps, respectively. There were 15 advanced neoplasms in 13 individuals (3.4%), of which 12 lesions were proximal to the sigmoid colon. There were no cancers at follow-up. Among individuals aged≥50 years, with normal baseline screening colonoscopy results, the incidence of advanced lesions at a second screening colonoscopy at least 8 years later was comparable to that in baseline screening studies. Our findings support current recommendations for screening at 10-year intervals in average-risk individuals.

Intermediate-risk patients with three to four small adenomas should be considered low risk for colorectal cancer screening.

Intermediate-risk patients following a colorectal cancer screening program may have differential risk of advanced lesions depending on the findings of an index colonoscopy. The aim of the present study was to comparatively assess advanced colorectal neoplasia risk at the first follow-up colonoscopy among the different intermediate-risk subgroups with a focus on patients with three to four adenomas. All patients recruited for a baseline screening colonoscopy between 2006 and 2011 were included. Number, size and histopathological characteristics of adenomas were collected. Main outcome was an advanced colorectal neoplasia detection rate (invasive carcinoma or advanced adenoma) at the first follow-up colonoscopy. Low- and high-risk patients were excluded. Five hundred and sixty-one intermediate-risk patients (63.3% men, mean age: 59.01±6.16 years) underwent indexing and follow-up colonoscopy. By multivariate analysis, three to four adenomas (OR: 3.613 [95% CI: 1.661-7.859], P=0.001) and adenoma size ≥10<20mm (OR: 3.374 [95% CI: 1.618-7.034], P=0.001) were independent factors associated with advanced colorectal neoplasia. Advanced lesions were detected in 7.66% of cases. Of patients with advanced colorectal neoplasia, 51.16% belonged to the three-to-four-adenoma group and ≥1 of ≥10<20-mm subgroups (n=132, 23.53%). These patients demonstrated a higher rate of advanced lesions [OR: 3.886 (95% CI: 2.061-7.325), P<0.001] than patients with three to four small adenomas of <10mm (16.67% vs 5.07%, P<0.001). The association between patients with small adenomas (n=217, 38.68%) and advanced lesions was not significant (OR: 0.521 [95% CI: 0257-1.056], P=0.066). Intermediate-risk patients with three to four small adenomas achieved a very low advanced lesion rate at follow up. Surveillance interval should be lengthened because these patients should be considered low risk.

Evaluation of Two Flexible Colonoscopy Simulators and Transfer of Skills into Clinical Practice

Surgical residents have learned flexible endoscopy by practicing on patients in hospital settings under the strict guidance of experienced surgeons. Simulation is often used to "pretrain" novices on endoscopic skills before real clinical practice; nonetheless, the optimal method of training remains unknown. The purpose of this study was to compare endoscopic virtual reality and physical model simulators and their respective roles in transferring skills to the clinical environment. At the beginning of a skills development rotation, 27 surgical postgraduate year 1 residents performed a baseline screening colonoscopy on a real patient under faculty supervision. Their performances were scored using the Global Assessment of Gastrointestinal Endoscopic Skills (GAGES). Subsequently, interns completed a 3-week flexible endoscopy curriculum developed at our institution. One-third of the residents were assigned to train with the GI Mentor simulator, one-third trained with the Kyoto simulator, and one-third of the residents trained using both simulators. At the end of their rotations, each postgraduate year 1 resident performed one posttest colonoscopy on a different patient and was again scored using GAGES by an experienced faculty. A statistically significant improvement in the GAGES total score (p < 0.001) and on each of its subcomponents (p = 0.001) was observed from pretest to posttest for all groups combined. Subgroup analysis indicated that trainees in the GI Mentor or both simulators conditions showed significant improvement from pretest to posttest in terms of GAGES total score (p = 0.017 vs 0.024, respectively). This was not observed for those exclusively using the Kyoto platform (p = 0.072). Nonetheless, no single training condition was shown to be a better training modality when compared to others in terms of total GAGES score or in any of its subcomponents. Colonoscopy simulator training with the GI Mentor platform exclusively or in combination with a physical model simulator improves skill performance in real colonoscopy cases when measured with the GAGES tool.

Whites and Blacks Have Similar Risk of Metachronous Advanced Colorectal Neoplasia

Current guidelines for surveillance of colonic neoplasia are based on data from predominantly white populations, yet whether these recommendations are applicable to blacks is unknown. To define the prevalence of advanced colorectal neoplasia (ACN) among whites and blacks undergoing surveillance colonoscopy. This was a retrospective, cross-sectional analysis of asymptomatic, average-risk non-Hispanic white (N = 246) and non-Hispanic black (N = 203) patients with colorectal neoplasia who underwent baseline screening colonoscopy between January 1, 2000, and December 31, 2007, and a surveillance colonoscopy before December 31, 2010, at an academic safety-net hospital. The main outcome measure was the prevalence of ACN, defined as a tubular adenoma or sessile serrated adenoma (SSA) ≥ 10 mm, any adenoma with villous histology or high-grade dysplasia, any serrated lesion with dysplasia, or invasive cancer at surveillance. During a median follow-up of 4.3 years, the overall prevalence of ACN at surveillance was similar among blacks and whites (11.3 vs. 9.8 %; P = 0.59) with an odds ratio of 1.18 (95 % CI 0.65-2.16) [corrected]. Blacks and whites with non-advanced neoplasia had similar rates of ACN at the 1-3, 4-5, and >5 year follow-up intervals. Blacks with ACN or multiplicity at baseline had higher rates of ACN at the 1- to 3-year interval compared with whites, but the difference was non-significant (26.7 vs. 12.5 %; P = 0.32). No interval cancers were observed for either group. The overall prevalence of ACN was similar between non-Hispanic blacks and non-Hispanic whites undergoing surveillance in a safety-net healthcare setting suggesting that current surveillance guidelines are appropriate for both blacks and whites.

Risk of colorectal tumor after negative baseline screening colonoscopy

Objective To review the following colonoscopy of negative baseline screening colonoscopy crowd,and to explore the risk of colorectal tumor at different time intervals in different gender,age and risk levels.Methods With bi-cohort study design,self-made questionnaire was used to survey the following colonoscopy of the asymptomatic average-risk population with negative baseline screening colonoscopy from January 1,1995 to December 31,2005.The survey contents included all the following colonoscopy,the risk stratification factors of colorectal cancer (age,gender,smoking status,history of diabetes,green vegetables intake,pickled food intake,fried smoked food intake,white meat intake).The life table survival analysis method was used to study the cumulative risk of colorectal tumor in different gender,age,risk levels.Results Four hundred and fifty-five cases were included,and there were 91 cases of colorectal polyp,24 cases of adenoma and 9 cases of advanced tumor.The cumulative prevalence rates of colorectal polyp,adenoma and advanced tumor during 5 years for negative baseline screening colonoscopy crowd were 11.9％,4.2％ and 2.0％ respectively.The cumulative prevalence rate of advanced tumor during 12 years was 3.9％.The risk of colorectal polyp of men was higher than that of female (x2 =8.142,P =0.004).The risk of colorectal polyp of ≥60 years group was higher than that of ＜60 years group (x2 =6.321,P =0.012).The risk of colorectal polyp of high risk group was higher than that of low risk group (x2 =4.082,P =0.043).Conclusion In the negative baseline screening colonoscopy crowd,5-year cumulative prevalence rates of colorectal polyp,adenoma,advanced tumor are low,and 12-year cumulative prevalence rate of colorectal advanced tumor is low too. Key words: Colorectal neoplasms; Colonoscopes

Why Do Women Have Lower Rates of Adenomas yet Similar Lifetime Risk of Colorectal Cancer?

Purpose: Women, when stratified by age, have lower rates of adenomas and advanced adenomas, versus men. Yet, the cumulative lifetime risk of colorectal cancer is similar in men and women. This conundrum has not been explained. Increasingly it is recognized that female gender and proximal colon location are associated with sessile serrated polyps and these lesions are believed to be a precursor for up to 20% of colorectal cancers. We determined if women have a higher prevalence of sessile serrated polyps (SSP) then men, which may, in part, explain the conundrum. Methods: Patients who underwent complete, baseline screening colonoscopy with adequate bowel preparation between 2008 and 2009 were identified. Demographics, polyp size, number, location, and histology were reviewed. Means and standard deviations for continuous variables and frequencies for categorical factors were calculated. Overall detection rates for Polyps (PDR), Adenomas (ADR) and SSP (SSPDR) as well as distal and proximal detection rates for these indices were determined for males and females. Paired t-tests were used to compare endoscopists' detection rates for female and male patients. Results: 3,337 patients who had colonoscopies performed by 66 endoscopists were included. 49.5% of subjects were male, average patient age was 62 years. Men were slightly younger than women (60 vs 61 years, p 0.049). Women had fewer polyps (0.54 vs 0.9, p <0.001) and adenomas (0.29 vs 0.5, p <0.001) than men. PDR and ADR were also significantly lower in women than men (31% vs 44% and 19% vs 31%, respectively, p <0.001 for both). ADR was significantly higher in the proximal than the distal colon in women, 12% versus 9% (p= 0.011) but this difference in location was not observed in men: 19% versus 17% (p=0.062). Unlike ADR, there was no difference in SSPDR between women and men, 1.4% vs 2% (p= 0.13) and the number of SSPs detected in women was the same as men, 0.02 vs 0.02, p 0.36. Significantly more SSP were found in the proximal than the distal colon in women, 1% versus 0.35% (p=0.034) but this was not the case in men 1.2% versus 0.77% (p=0.17). Conclusion: Women have a lower prevalence of and fewer adenomas than men. There is no gender difference between the prevalence and number of sessile serrated polyps. Women, but not men, have a significantly higher prevalence of proximal than distal adenomas and sessile serrated polyps. The lack of gender disparity in the prevalence and number of SSPs and tendency for proximal location of SSP and adenomas may account for the observation that women and men have similar cumulative lifetime risk of colorectal cancer yet lower rates of ADR.

Current Postpolypectomy Surveillance Guidelines Supported

The most recent postpolypectomy surveillance guidelines from the U.S. Multisociety Task Force on Colorectal Cancer and the American Cancer Society recommend that patients with one to two small tubular adenomas undergo a repeat colonoscopy in 5 to 10 years (Gastroenterology 2006; 130:1872). In the U.S., the majority of this population undergoes follow-up colonoscopy in ≤5 years. To estimate 5-year cumulative incidence of adenoma after baseline screening colonoscopy, investigators prospectively enrolled 3803 asymptomatic Koreans …

Five-Year Risk of Colorectal Neoplasia After Negative Screening Colonoscopy

Recommendation for a 10-year interval for screening colonoscopy in persons at average risk for colorectal cancer is based on retrospective case–control data. There are no data from prospective studies of sufficient size and duration. This retrospective study determined the incidence of adenomas among individuals with no adenomas on baseline screening colonoscopy who were rescreened at a 5-year follow-up. The participants were 50 years or older and had undergone first-time screening from 1995 to 2000. The incidence of the following categories were determined: a cancer; an advanced adenoma (a tubular adenoma ≥1 cm in diameter, a polyp with high-grade dysplasia, or a villous component of at least 25%); a tubular adenoma ≤1 cm in diameter, a hyperplastic polyp; or no polyp. Among the 2983 persons screened for the first time, 2436 (81.7%) had no adenomas on baseline screening colonoscopy. At a mean of 5.3 ± 1.3 years later, 1256 of those with no adenomas (51.6%) underwent follow-up colonoscopy. At the time of baseline screening, the mean age of the participants was 56.7 years; 544 (43.3%) were women (mean age 57.1 years) and 712 (56.7%) were men (mean age 56.4 years). Among the 1256 persons re-screened, there were no cancers [95% confidence interval (CI) for the detection rate, 0% to 0.24%]. One or more neoplastic polyps were identified in 201 persons (16.0%). A total of 19 advanced adenomas were identified in 16 persons (1.3%). No significant difference was found at baseline in the risk of an advanced adenoma among persons without polyps [1.1% (12 of 1057)] and those with hyperplastic polyps [2.0% (4 of 199); relative risk, 1.77; 95% CI, 0.61–5.14]. The risk of any adenoma or an advanced adenoma was higher in men than women (relative risk, 1.88; 95% CI, 1.42–2.51 and 3.31; 95% CI, 1.02–10.8, respectively). For 1 advanced adenoma to be detected among all 1256 persons with normal findings at baseline, 79 would need to be rescreened at 5 years. Among women, 182 would need to be rescreened, whereas among men, 55 would need to be rescreened. These findings are consistent with previous data and support a rescreening interval of 5-years or longer after a normal colonoscopic examination in persons of average risk for colorectal cancer. The risk of an advanced adenoma is lower in women than in men.

Five-Year Risk of Colorectal Neoplasia after Negative Screening Colonoscopy

The appropriate interval for endoscopic rescreening after a negative colonoscopic examination is uncertain. We identified persons with no adenomas on baseline screening colonoscopy who returned at 5 years for follow-up colonoscopy. Findings were categorized according to the most advanced lesion present: no polyp, a hyperplastic polyp, a tubular adenoma less than 1 cm in diameter, an advanced adenoma (a tubular adenoma > or = 1 cm in diameter or a polyp with villous histologic features or high-grade dysplasia), or a cancer. Baseline screening colonoscopy had identified 2436 persons with no adenomas; 1256 of them (51.6%) were rescreened a mean (+/-SD) of 5.34+/-1.34 years later. The mean age of this group at baseline was 56.7 years; 56.7% of its members were men. No cancers were found on rescreening (95% confidence interval [CI] for the detection rate, 0 to 0.24%). One or more adenomas were found in 201 persons (16.0%). A total of 19 advanced adenomas, of which 10 (52.6%) were distal to the splenic flexure, were found in 16 persons (1.3%). The risk of an advanced adenoma did not differ significantly between persons with no polyps at baseline and those with hyperplastic polyps at baseline (1.1% [12 of 1057] and 2.0% [4 of 199], respectively; P=0.30). Men were more likely than women to have any adenoma (tubular less than 1 cm in diameter or advanced) (relative risk, 1.88; 95% CI, 1.42 to 2.51) and to have an advanced adenoma (relative risk, 3.31; 95% CI, 1.02 to 10.8). Among persons with no colorectal neoplasia on initial screening colonoscopy, the 5-year risk of colorectal cancer is extremely low. The risk of advanced adenoma is also low, although it is higher among men than among women. Our findings support a rescreening interval of 5 years or longer after a normal colonoscopic examination.

Postpolypectomy Colonoscopy Surveillance Guidelines: Predictive Accuracy for Advanced Adenoma at 4 Years

Lack of confidence in postpolypectomy surveillance guidelines may be a factor in the observed low adherence rates among providers. To assess the 2006 postpolypectomy colonoscopy surveillance guidelines, which recommend 3-year follow-up colonoscopy for individuals with high-risk adenomas (defined as > or =3 adenomas or any advanced adenomas) and 5- to 10-year follow-up for patients with 2 or fewer nonadvanced adenomas, who are considered to be at low risk. Analysis of prospective data from the Polyp Prevention Trial. United States. 1905 patients who had colorectal adenomas removed at baseline screening or diagnostic colonoscopy and completed the trial. Baseline adenoma characteristics, risk-stratified according to definitions used in the guidelines, were examined as predictors for advanced adenoma recurrence. 125 patients (6.6%) had advanced and 629 (33.0%) had nonadvanced adenoma recurrence; 1151 (60.4%) had no recurrence within 4 years of follow-up. The probability of advanced adenoma recurrence was 0.09 (95% CI, 0.07 to 0.11) among patients with high-risk adenomas at baseline and 0.05 (CI, 0.04 to 0.06) among those with low-risk adenomas at baseline. The relative risk for advanced adenoma recurrence for patients with high-risk adenomas versus those with low-risk adenomas at baseline was 1.68 (CI, 1.19 to 2.38) when advanced adenoma recurrence was compared with no advanced adenoma recurrence and 1.76 (CI, 1.26 to 2.46) when advanced adenoma recurrence was compared with no adenoma recurrence. The c-statistics for these 2 comparisons were 0.68 and 0.72, respectively. Participants were self-selected and had restrictions on the degree of obesity. Although the risk for recurrence of advanced adenoma within 4 years is greater for patients with high-risk adenomas at baseline than for those with low-risk adenomas, the discrimination of this risk stratification scheme is relatively low.

Five-Year Colon Surveillance After Screening Colonoscopy

Outcomes of colon surveillance after colorectal cancer screening with colonoscopy are uncertain. We conducted a prospective study to measure incidence of advanced neoplasia in patients within 5.5 years of screening colonoscopy. Three thousand one hundred twenty-one asymptomatic subjects, age 50 to 75 years, had screening colonoscopy between 1994 and 1997 in the Department of Veterans Affairs. One thousand one hundred seventy-one subjects with neoplasia and 501 neoplasia-free controls were assigned to colonoscopic surveillance over 5 years. Cohorts were defined by baseline findings. Relative risks for advanced neoplasia within 5.5 years were calculated. Advanced neoplasia was defined as tubular adenoma greater than > or =10 mm, adenoma with villous histology, adenoma with high-grade dysplasia, or invasive cancer. Eight hundred ninety-five (76.4%) patients with neoplasia and 298 subjects (59.5%) without neoplasia at baseline had colonoscopy within 5.5 years; 2.4% of patients with no neoplasia had interval advanced neoplasia. The relative risk in patients with baseline neoplasia was 1.92 (95% CI: 0.83-4.42) with 1 or 2 tubular adenomas <10 mm, 5.01 (95% CI: 2.10-11.96) with 3 or more tubular adenomas <10 mm, 6.40 (95% CI: 2.74-14.94) with tubular adenoma > or =10 mm, 6.05 (95% CI: 2.48-14.71) for villous adenoma, and 6.87 (95% CI: 2.61-18.07) for adenoma with high-grade dysplasia. There is a strong association between results of baseline screening colonoscopy and rate of serious incident lesions during 5.5 years of surveillance. Patients with 1 or 2 tubular adenomas less than 10 mm represent a low-risk group compared with other patients with colon neoplasia.

Five-Year Risk of Colorectal Neoplasia among Persons with No Neoplasia on Baseline Screening Colonoscopy

Purpose: Few data support the recommended re-screening interval for persons with no colorectal neoplasia. Our objective was to measure the risk of colorectal neoplasia in persons whose baseline screening colonoscopy (CY) showed no neoplasia. Methods: From an 11-year old corporate-sponsored program of screening CY, we identified persons with no adenomas on 1st-time screening between 9/95 and 6/00, who returned for a recommended 5-year re-screening exam. For this analysis, the distal bowel includes the descending colon, sigmoid colon and rectum. Each bowel segment was categorized according to the most advanced lesion present, classified as no polyps; hyperplastic polyp(s) (HP); tubular adenoma < 1 cm; advanced adenoma(s) (AA), defined as a tubular adenoma ≥ 1cm, or a polyp with villous histology or high-grade dysplasia; or cancer. Results: 2436 persons had no adenomas at baseline; 1256 (51.6%) returned for re-screening CY a mean of 5.34 ± 1.34 years later. Re-screened persons were younger than the 1180 non-re-screened persons (54.7 vs. 58.3 years; p < 0.001), but were comparable in gender profile (57% vs. 53% men). No cancers were found on re-screening (95% CI, 0–0.24%); 201 persons (16%; CI, 14–18%) had ≥ 1 adenoma: 34% distal only, 40% proximal only, and 27% proximal and distal. Adenomas were more common in persons with HPs vs. no polyps at baseline (47 of 199 [23.6%] vs. 154 of 1057 [14.6%]; RR = 1.62 (CI, 1.21–2.15) despite comparable mean age (57.2 vs. 56.6 years; p= 0.34). Fifteen persons (1.2%; CI, 0.67–1.96%) had AAs, with similar risk between persons with baseline HPs (2%) vs. those with no polyps (1%) (p= 0.25). Men were more likely to have any adenoma (20.1% vs. 10.7%; RR = 1.88; CI, 1.42–2.51) and an AA (1.7% vs. 0.55%; RR = 3.07; CI, 0.94–10.12). Among 388 women < age 60 at baseline, 1 (0.26%; CI, 0.01% to 1.43%) had an AA. Among 634 persons < age 55 at baseline, 7 (1.1%; CI, 0.45% to 2.26%) had an AA. Conclusions: Among previously screened persons with no colorectal neoplasia, the 5-year risk of colorectal cancer is extremely low. The risk of an AA is also low, though higher in men than in women. It is likely that re-screening may safely be performed beyond 5 years.

New occurrence and recurrence of neoplasms within 5 years of a screening colonoscopy

OBJECTIVE: The fear that colorectal adenomas were missed on initial colonoscopy or that new adenomas have developed is often a rationale for repeating a colonoscopic examination. The aim of this study was to delineate risk factors associated with recurrence of colorectal adenomas after an initial baseline screening colonoscopy. METHODS: The study population comprised 875 subjects who underwent a baseline screening colonoscopy followed by a second examination 1–5 yr later. Multiple logistic regression was used to assess the influence of potential risk factors on the occurrence or recurrence of colorectal adenomas, the strength of the influence being expressed as an OR with a 95% CI. RESULTS: Colorectal adenomas were detected in 484 of all patients (55%) at baseline colonoscopy. Within a 1- to 5-yr time interval, 181 patients (37%) had recurrent adenomas (adenomas were removed during the first colonoscopy) and 73 patients (19%) had newly developed adenomas (adenomas were absent on the first colonoscopy). The occurrence of adenomas at baseline screening colonoscopy was the only factor associated with an increased risk for the recurrence of adenomas at follow-up (OR = 2.51, 95% CI = 1.77–3.55). Recurrence was associated with multiple baseline adenomas (4.45, 2.98–6.64) and baseline adenomas larger than 1 cm (2.62, 1.99–3.11). Recurrence was not associated with histology type or family history of colorectal cancer. There was a significant trend for adenomas to recur in the same proximal or distal segment as the baseline adenomas ( p = 0.02). CONCLUSIONS: Colon adenomas tend to recur with greater frequency if the adenomas removed at baseline were either large or multiple. Although patients with large adenomas or multiple adenomas at baseline screening colonoscopy are at a 2.6- to 4.5-fold risk for recurrence of adenomas, the rate of de novo adenoma formation in patients without baseline adenomas may be large enough to warrant repeat colonoscopy at some time in the future. The exact timing of the follow-up colonoscopy needs to be determined.