Colorectal Cancer Incidence and Mortality After Removal of Adenomas During Screening Colonoscopies.

BACKGROUND & AIMS: Recommendation of surveillance colonoscopy should be based on risk of colorectal cancer and death after adenoma removal. We aimed to develop a risk classification system based on colorectal cancer incidence and mortality following adenoma removal. METHODS: We performed a multicenter population-based cohort study of 236,089 individuals (median patient age, 56 years; 37.8% male) undergoing screening colonoscopies with adequate bowel cleansing and cecum intubation at 132 centers in the Polish National Colorectal Cancer Screening Program, from 2000 through 2011. Subjects were followed for a median 7.1 years and information was collected on colorectal cancer development and death. We used recursive partitioning and multivariable Cox models to identify associations between colorectal cancer risk and patient and adenoma characteristics (diameter, growth pattern, grade of dysplasia, and number of adenomas). We developed a risk classification system based on standardized incidence ratios, using data from the Polish population for comparison. The primary endpoints were colorectal cancer incidence and colorectal cancer death. RESULTS: We identified 130 colorectal cancers in individuals who had adenomas removed at screening (46.5 per 100,000 person-years) vs 309 in individuals without adenomas (22.2 per 100,000 person-years). Compared with individuals without adenomas, adenomas ≥20 mm in diameter and high-grade dysplasia were associated with increased risk of colorectal cancer (adjusted hazard ratios 9.25; 95% confidence interval [CI] 6.39-13.39, and 3.58; 95% CI 1.96-6.54, respectively). Compared with the general population, colorectal cancer risk was higher or comparable only for individuals with adenomas ≥20 mm in diameter (standardized incidence ratio [SIR] 2.07; 95% CI 1.40-2.93) or with high-grade dysplasia (SIR 0.79; 95% CI 0.39-1.41), whereas for individuals with other adenoma characteristics the risk was lower (SIR 0.35; 95% CI 0.28-0.44). We developed a high-risk classification based on adenoma size ≥20 mm or high-grade dysplasia (instead of the current high-risk classification cutoff of ≥3 adenomas or any adenoma with villous growth pattern, high-grade dysplasia, or ≥10 mm in diameter). Our classification system would reduce the number of individuals classified as high-risk and requiring intensive surveillance from 15,242 (36.5%) to 3980 (9.5%), without increasing risk of colorectal cancer in patients with adenomas (risk difference per 100,000 person-years, 5.6; 95% CI -10.7 to 22.0). CONCLUSIONS: Using data from the Polish National Colorectal Cancer Screening Program, we developed a risk classification system that would reduce the number of individuals classified as high risk and require intensive surveillance more than 3-fold, without increasing risk of colorectal cancer in patients with adenomas. This system could optimize the use of surveillance colonoscopy.

Long-Term Colorectal Cancer Incidence and Mortality After a Single Negative Screening Colonoscopy.

BACKGROUND: Current guidelines recommend a 10-year interval between screening colonoscopies, but evidence is limited. OBJECTIVE: To assess the long-term risk for colorectal cancer (CRC) and death from CRC after a high- and low-quality single negative screening colonoscopy. DESIGN: Observational study. SETTING: Polish Colonoscopy Screening Program. PARTICIPANTS: Average-risk individuals aged 50 to 66 years who had a single negative colonoscopy (no neoplastic findings). MEASUREMENTS: Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) of CRC after high- and low-quality single negative screening colonoscopy. High-quality colonoscopy included a complete examination, with adequate bowel preparation, performed by endoscopists with an adenoma detection rate of 20% or greater. RESULTS: Among 165 887 individuals followed for up to 17.4 years, CRC incidence (0.28 [95% CI, 0.25 to 0.30]) and mortality (0.19 [CI, 0.16 to 0.21]) were 72% and 81% lower, respectively, than in the general population. High-quality examination resulted in 2-fold lower CRC incidence (SIR, 0.16 [CI, 0.13 to 0.20]) and mortality (SMR, 0.10 [CI, 0.06 to 0.14]) than low-quality examination (SIR, 0.32 [CI, 0.29 to 0.35]; SMR, 0.22 [CI, 0.18 to 0.25]). In multivariable analysis, the hazard ratios for CRC incidence after high-quality versus low-quality colonoscopy were 0.55 (CI, 0.35 to 0.86) for 0 to 5 years, 0.54 (CI, 0.38 to 0.77) for 5.1 to 10 years, and 0.46 (CI, 0.25 to 0.86) for 10 to 17.4 years. Only after high-quality colonoscopy did the SIR and SMR for 10.1 to 17.4 years of follow-up not differ compared with earlier observation periods. LIMITATION: The general population was used as the comparison group. CONCLUSION: A single negative screening colonoscopy was associated with reduced CRC incidence and mortality for up to 17.4 years. Only high-quality colonoscopy yielded profound and stable reductions in CRC incidence and mortality throughout the entire follow-up. PRIMARY FUNDING SOURCE: Polish Ministry of Health.

The impact of low- versus standard-volume bowel preparation on participation in primary screening colonoscopy: a randomized health services study.

BACKGROUND: The aim of this study was to evaluate the impact of low-volume vs. standard-volume bowel preparation on participation in screening colonoscopy, bowel preparation quality, and lesion detection rates. METHODS: This was a multicenter, randomized, health services study within the population-based primary colonoscopy screening program in Poland. Individuals aged 55 - 62 years were randomized in a 1:1 ratio to bowel preparation with a low-volume (0.3 L sodium picosulfate with magnesium citrate) or standard-volume (4 L polyethylene glycol) regimen and then invited to participate in screening colonoscopy. The primary outcome measure was the rate of participation in screening colonoscopy. Compliance with the assigned bowel preparation, bowel preparation quality, and lesion detection rates were also evaluated. RESULTS: A total of 13 621 individuals were randomized and 13 497 were analyzed (6752 in the low-volume group and 6745 in the standard-volume group). The participation rate (16.6 % vs. 15.5 %; P = 0.08) and compliance rate (93.3 % vs. 94.1 %; P = 0.39) did not differ significantly between the groups. In the low-volume group, fewer participants had adequate bowel preparation compared with the standard-volume group (whole colon 79.0 % vs. 86.4 %, P < 0.001; proximal colon 80.1 % vs. 87.3 %, P < 0.001). Detection rates of advanced adenoma (AADR) and advanced serrated polyps (ASPDR) were lower in the low-volume group than in the standard-volume group (AADR in the proximal colon 2.6 % vs. 4.3 %, P = 0.02; ASPDR in the whole colon 2.0 % vs. 3.3 %, P = 0.04; ASPDR in the proximal colon 1.0 % vs. 1.9 %, P = 0.048). CONCLUSION: When compared with a standard-volume bowel preparation with polyethylene glycol, low-volume bowel preparation with sodium picosulfate/magnesium citrate did not improve participation rate or lesion detection rates, and negatively affected bowel preparation quality.

Increased Rate of Adenoma Detection Associates With Reduced Risk of Colorectal Cancer and Death.

BACKGROUND & AIMS: The quality of endoscopists' colonoscopy performance is measured by adenoma detection rate (ADR). Although ADR is associated inversely with interval colorectal cancer and colorectal cancer death, the effects of an increasing ADR have not been shown. We investigated whether increasing ADRs from individual endoscopists is associated with reduced risks of interval colorectal cancer and subsequent death. METHODS: We performed a prospective cohort study of individuals who underwent a screening colonoscopy within the National Colorectal Cancer Screening Program in Poland, from January 1, 2004, through December 31, 2008. We collected data from 146,860 colonoscopies performed by 294 endoscopists, with each endoscopist having participated at least twice in annual editions of primary colonoscopy screening. We used annual feedback and quality benchmark indicators to improve colonoscopy performance. We used ADR quintiles in the whole data set to categorize the annual ADRs for each endoscopist. An increased ADR was defined as an increase by at least 1 quintile category, or the maintenance of the highest category in subsequent screening years. Multivariate frailty models were used to evaluate the effects of increased ADR on the risk of interval colorectal cancer and death. RESULTS: Throughout the enrollment period, 219 endoscopists (74.5%) increased their annual ADR category. During 895,916 person-years of follow-up evaluation through the National Cancer Registry, we identified 168 interval colorectal cancers and 44 interval cancer deaths. An increased ADR was associated with an adjusted hazard ratio for interval colorectal cancer of 0.63 (95% confidence interval [CI], 0.45-0.88; P = .006), and for cancer death of 0.50 (95% CI, 0.27-0.95; P = .035). Compared with no increase in ADR, reaching or maintaining the highest quintile ADR category (such as an ADR > 24.56%) decreased the adjusted hazard ratios for interval colorectal cancer to 0.27 (95% CI, 0.12-0.63; P = .003), and 0.18 (95% CI, 0.06-0.56; P = .003), respectively. CONCLUSIONS: In a prospective study of individuals who underwent screening colonoscopy within a National Colorectal Cancer Screening Program, we associated increased ADR with a reduced risk of interval colorectal cancer and death.