Risk of developing metachronous advanced colorectal neoplasia after resection of low-risk diminutive versus small adenomas

What do 'false-positive' stool tests really mean? Data from the New Hampshire colonoscopy registry

We utilized the population-based New Hampshire Colonoscopy Registry to calculate false discovery rates (FDR) and positive predictive values (PPVs) using three 'positive' colonoscopy definitions. Understanding the frequency of meaningful 'true positive' mt-sDNA and Fecal Immunochemical Test (FIT) results can optimize the use of these colorectal cancer (CRC) screening tests. We calculated FDR (positive stool test followed by negative colonoscopy divided by all positive stool tests) and PPV for mt-sDNA and FIT cohorts using the following definitions: 1) DeeP-C Study (CRC, adenomas/serrated polyps ≥ 1 cm, villous/High Grade Dysplasia); 2) < 10 year US Multi-Society Task Force (USMSTF) follow-up: DeeP-C findings & ≥1 sessile serrated polyps (SSPs) < 1 cm (with/without dysplasia) or ≥ 1 tubular adenomas < 1 cm. 3) Clinically Significant: DeeP-C + USMSTF + clinically significant serrated polyps: traditional serrated adenomas, SSPs, hyperplastic polyps (HPs) > 1 cm, and 5-9 mm proximal HPs. The sample included 549 mt-sDNA + and 410 FIT + and patients (mean age 66.4, 43.0% male). Using the most limited definition of positive colonoscopy, DeeP-C, FDR was 71.9% for mt-sDNA + and 81.7% for FIT +. Using the USMSTF definition, FDR decreased substantially: mt-sDNA+:33.2% and FIT+:47.6%. Adding all CSSPs resulted in the lowest FDR: mt-sDNA+:32.2% and FIT+:47.1%. Decreasing FDRs corresponded to increasing PPVs: mt-sDNA+:28.1% and FIT+:18.3% (DeeP-C definition) and mt-sDNA+:67.8% and FIT+:52.9% (DeeP-C + USMSTF + CSSP) (Table 1). FDRs decreased substantially when the definition of positive exams included all significant precancerous findings. These data present a comprehensive understanding of false positive outcomes at colonoscopies following positive stool tests, which to our knowledge is the first such analysis.

Risk Factors for Metachronous Colorectal Cancer or Advanced Adenomas After Endoscopic Resection of High-risk Adenomas

BACKGROUND & AIMS

Among the characteristics of high-risk adenomas (HRAs), some may predict a higher risk of metachronous advanced lesions. Our aim was to assess which HRA characteristics are associated with high risk of metachronous colorectal cancer (CRC) or advanced adenomas (AAs).

METHODS

We systematically searched Pubmed, EMBASE, and Cochrane for cohort studies and clinical trials of CRC or AA incidence at surveillance stratified by baseline lesion size, histology, and multiplicity. We calculated pooled relative risks (RRs) using a random-effects model. Heterogeneity was assessed with the I² statistic.

RESULTS

Fifty-five studies were included, with 936,540 patients with mean follow-up 5.4 ± 2.9 years. CRC incidence per 1000 person-years was 2.6 (2.1-3.0) for adenomas ≥20 mm, 2.7 (2.2-3.2) for high-grade dysplasia (HGD), 2.0 (1.8-2.3) for villous component, 0.8 (0.1-1.4) for ≥5 adenomas, 1.0 (0.7-1.2) for ≥3 adenomas. Metachronous CRC risk was higher in adenomas ≥20 mm vs 10 to 19 mm (RR, 2.08; 95% confidence interval [CI], 1.20-3.61), HGD vs low-grade dysplasia (RR, 2.89; 95% CI, 1.88-4.44), villous vs tubular (RR, 1.75; 95% CI, 1.33-2.31). No significant differences in CRC risk were found in ≥3 adenomas vs 1 to 2 (RR, 1.24; 95% CI, 0.84-1.83), nor in ≥5 adenomas vs 3 to 4 (RR, 0.79; 95% CI, 0.30-2.11). Compared with normal colonoscopy, RR for CRC risk was 2.61 (95% CI, 2.06-3.32) for ≥10mm, 6.62 (95% CI, 4.60-9.52) for HGD, 3.58 (95% CI, 2.24-5.73) for villous component, and 2.03 (95% CI, 1.40-2.94) for ≥3 adenomas. Similar trends were seen for metachronous AAs.

CONCLUSION

Metachronous CRC risk is highest in patients with baseline adenomas with ≥20 mm or HGD. Multiplicity does not seem to be associated with substantially higher CRC risk in the near term.

Risk of Metachronous Advanced Colorectal Neoplasia After Removal of Diminutive Versus Small Nonadvanced Adenomas: A Multicenter Study

BACKGROUND

Current postpolypectomy guidelines treat 1-9 mm nonadvanced adenomas (NAAs) as carrying the same level of risk for metachronous advanced colorectal neoplasia (ACRN).

AIMS

To evaluate whether small (6-9 mm) NAAs are associated with a greater risk of metachronous ACRN than diminutive (1-5 mm) NAAs.

METHODS

We retrospectively evaluated 10,060 index colonoscopies performed from July 2011 to June 2019. A total of 1369 patients aged ≥ 40 years with index NAAs and having follow-up examinations were categorized into 5 groups based on size and number of index findings: Group 1, ≤ 2 diminutive NAAs (n = 655); Group 2, ≤ 2 small NAAs (n = 529); Group 3, 3-4 diminutive NAAs (n = 78); Group 4, 3-4 small NAAs (n = 65); and Group 5, 5-10 NAAs (n = 42). Size was classified based on the largest NAA. ACRN was defined as finding an advanced adenoma or colorectal cancer at follow-up.

RESULTS

The absolute risk of metachronous ACRN increased from 7.2% in patients with all diminutive NAAs to 12.2% in patients with at least 1 small NAA (P = 0.002). Patients in Group 2 (adjusted odds ratio [AOR] 1.89; 95% confidence interval [CI], 1.21-2.95), Group 3 (AOR 2.40; 95% CI 1.78-4.90), Group 4 (AOR 2.77; 95% CI 1.35-5.66), and Group 5 (AOR 3.71; 95% CI 1.65-8.37) were associated with an increased risk of metachronous ACRN compared with Group 1.

CONCLUSIONS

Patients with small NAAs have an increased risk of metachronous ACRN. Postpolypectomy guidelines should consider including risk stratification between small and diminutive adenomas.

The risk of advanced neoplasia after polypectomy of one to two non-advanced adenomas less than 5 mm in size vs. normal colonoscopy

BACKGROUND

Current guidelines are inconsistent regarding the follow-up of patients with 1-2 diminutive (1-5 mm) non-advanced adenomas (DNAAs).

AIMS

To evaluate the risk of metachronous advanced neoplasia (AN), defined as cancer or advanced adenoma (AA), among patients with either normal colonoscopy or 1-2 DNAAs.

METHODS

A retrospective cohort study. Cohort I included 2,347 subjects with normal colonoscopy and 483 subjects with polypectomy of 1-2 DNAAs followed by colonoscopy. Cohort II included 11,881 subjects with normal colonoscopy and 1,342 subjects with 1-2 DNAAs followed through the cancer registry.

RESULTS

In cohort I, the rate of AN, cancer and AA among the polypectomy group vs. normal colonoscopy was 5.0% vs. 2.5%, Hazard Ratio (HR) 2.96 (95%CI [Confidence Interval]1.86-4.78) for AN; 0.6% vs. 0.3%, HR 3.32 (95%CI 0.85-13) for cancer; 4.3% vs. 2.2% HR 2.91 (95%CI 1.75-4.86) for AA. In cohort II, cancer occurred in 0.4% of the polypectomy group and 0.2% of the normal colonoscopy group, HR 2.27 (95% CI 0.56-9.19).

CONCLUSION

Compared to subjects with normal colonoscopy, subjects with polypectomy of 1-2 DNAAs, are at increased risk for AA when followed by colonoscopy, while the risk for cancer is non-significantly increased. Our findings suggest that patients with 1-2 DNNAs should be followed more tightly than patients with normal colonoscopy.

Yield and Risk Factors for Advanced Colorectal Neoplasia and Long-term Outcomes in Veterans With 3 or More Nonadvanced Adenomas

BACKGROUND AND AIMS

Until recently, guidelines recommended a 3-year surveillance colonoscopy for persons with 3 to 10 nonadvanced adenomas (NAA). In this study, we quantify yield for metachronous advanced neoplasia (AN); attempt to identify risk factors for AN; and measure colorectal cancer (CRC) incidence and mortality.

METHODS

We used natural language processing to screen an existing data set for Veterans with 3 to 10 NAA. We manually reviewed colonoscopy and pathology reports to verify baseline findings and determine results of subsequent colonoscopy (sCY). Baseline features were extracted from the electronic medical record (EMR) and a national data set, CRC incidence was obtained from the Veterans Affairs cancer registry, and CRC mortality from the National Death Index through September 30, 2017. CRC incidence and mortality were compared between Veterans who did versus did not have sCY.

RESULTS

Natural language processing identified 3673 Veterans who potentially had 3 to 10 NAA, of which 1672 were excluded after EMR review. In the analytical cohort of 2001 subjects, 1178 (59%) had sCY at a mean (SD) follow-up of 4.3 (2.2) years. The sCY group was younger (mean age: 61 vs. 67 y; P<0.01) and were less likely to have diabetes (27% vs. 31%; P=0.02) and congestive heart failure (4% vs. 9%; P<0.01). sCY showed AN in 182 subjects (15.5%). Baseline features were no different between those with versus without metachronous AN. Subjects with sCY had a greater CRC incidence (n=7 vs. n=0; P=0.046), but there was no difference in CRC mortality (0 for both subgroups).

CONCLUSIONS

Among patients with 3 to 10 NAA on index colonoscopy who underwent sCY, AN was present in 15.5% at mean follow-up of 4.3 years. No risk factors for AN were identified. CRC incidence, but not CRC mortality, was higher among those with sCY.

Bowel preparation with 1L polyethylene glycol and ascorbate NER1006 doubles the chance to detect three or more adenomas in overweight or obese males

Background and study aims  Men have more colon cleansing failures, colorectal adenomas, and colorectal cancers than women. We analyzed whether 1-liter (1 L) polyethylene glycol (PEG) NER1006 improves high-quality (HQ) colon cleansing and adenoma detection in males versus two mid-volume alternatives. Patients and methods  The analysis of 1028 adult patients in two randomized clinical trials was performed. Adenoma detection and HQ cleansing were compared for overnight split dosing regimens with NER1006 (n = 513) versus combined oral sulfate solution or 2 L PEG + ascorbate (OSS/2 L PEG) (n = 515). Analyses included males versus females, overweight or obese (OO) males versus lean males, and NER1006 versus OSS/2 L PEG. In male patients, the adenoma detection rate of at least 3 (ADR3 +) was predicted with multiple logistic regression and statistical comparisons used the two-sided t-test. Results  ADR3 + was greater in males versus females (10.7 % [56/524] versus 5.8 % [29/504]; P = 0.004) despite comparable adequate cleansing success rates (93.2 % [479/514] versus 93.0 % [466/501]; P = 0.912) and more HQ-scores in females (41.6 % [1069/2570] versus 45.3 % [1134/2505]; P = 0.008). ADR was almost twice as high in OO versus lean males (43.4 % [184/424] versus 23.1 % [21/91]; P < 0.001). Multivariate logistic regression predicted ADR3 + detection to be twice as likely in OO males using NER1006 versus OSS/2 L PEG (odds ratio (95 % confidence interval [CI]) = 2.049 (1.082-3.973); P = 0.030) and 90 % more likely in all males (1.902 (1.045-3.526); P = 0.037). In males, including OO males, NER1006 attained more HQ-scores per trial than OSS or 2 L PEG (P ≤ 0.017 for all comparisons). Conclusions  NER1006 predicted the detection of more males for frequent surveillance than OSS/2 L PEG.