Abstract Purpose Multiple cancer screening tests have been advocated for the general population; however, clinicians and patients are not always well-informed of screening burdens. We sought to ...determine the cumulative risk of a false-positive screening result and the resulting risk of a diagnostic procedure for an individual participating in a multimodal cancer screening program. Methods Data were analyzed from the intervention arm of the ongoing Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, a randomized controlled trial to determine the effects of prostate, lung, colorectal, and ovarian cancer screening on disease-specific mortality. The 68,436 participants, aged 55 to 74 years, were randomized to screening or usual care. Women received serial serum tests to detect cancer antigen 125 (CA-125), transvaginal sonograms, posteroanterior-view chest radiographs, and flexible sigmoidoscopies. Men received serial chest radiographs, flexible sigmoidoscopies, digital rectal examinations, and serum prostate-specific antigen tests. Fourteen screening examinations for each sex were possible during the 3-year screening period. Results After 14 tests, the cumulative risk of having at least 1 false-positive screening test is 60.4% (95% CI, 59.8%-61.0%) for men, and 48.8% (95% CI, 48.1%-49.4%) for women. The cumulative risk after 14 tests of undergoing an invasive diagnostic procedure prompted by a false-positive test is 28.5% (CI, 27.8%-29.3%) for men and 22.1% (95% CI, 21.4%-22.7%) for women. Conclusions For an individual in a multimodal cancer screening trial, the risk of a false-positive finding is about 50% or greater by the 14th test. Physicians should educate patients about the likelihood of false positives and resulting diagnostic interventions when counseling about cancer screening.
Background Gastroenterology specialty societies have advocated that providers routinely assess their performance on colonoscopy quality measures. Such routine measurement has been hampered by the ...costs and time required to manually review colonoscopy and pathology reports. Natural language processing (NLP) is a field of computer science in which programs are trained to extract relevant information from text reports in an automated fashion. Objective To demonstrate the efficiency and potential of NLP-based colonoscopy quality measurement. Design In a cross-sectional study design, we used a previously validated NLP program to analyze colonoscopy reports and associated pathology notes. The resulting data were used to generate provider performance on colonoscopy quality measures. Setting Nine hospitals in the University of Pittsburgh Medical Center health care system. Patients Study sample consisted of the 24,157 colonoscopy reports and associated pathology reports from 2008 to 2009. Main Outcome Measurements Provider performance on 7 quality measures. Results Performance on the colonoscopy quality measures was generally poor, and there was a wide range of performance. For example, across hospitals, the adequacy of preparation was noted overall in only 45.7% of procedures (range 14.6%-86.1% across 9 hospitals), cecal landmarks were documented in 62.7% of procedures (range 11.6%-90.0%), and the adenoma detection rate was 25.2% (range 14.9%-33.9%). Limitations Our quality assessment was limited to a single health care system in western Pennsylvania. Conclusions Our study illustrates how NLP can mine free-text data in electronic records to measure and report on the quality of care. Even within a single academic hospital system, there is considerable variation in the performance on colonoscopy quality measures, demonstrating the need for better methods to regularly and efficiently assess quality.
Background and Objective Diagnosis of colorectal cancer after negative findings on endoscopic evaluation raises concern about the effectiveness of endoscopic screening. We contrast screening-detected ...cancers with cancers not detected by screening among participants assigned to flexible sigmoidoscopy (FSG) in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial to determine the reasons for the lack of detection of prevalent lesions. Design Cancers detected within 1 year of a screening FSG with abnormal findings were classified as screening detected. All other cancers were categorized, based on cancer stage and years until detection, as either not detectable or prevalent but not detected at the time of screening. Setting/Patients A total of 77,447 subjects in the multicenter PLCO trial. Main Outcome Measurements A total of 977 colorectal cancers were diagnosed with a mean follow-up of 11.5 years. Results A total of 243 (24.9%) cancers were screening detected, 470 (48.1%) were not detectable at screening, and 264 (27.0%) were considered prevalent but not detected. Among prevalent nondetected lesions, 35.6% (n = 94) were attributed to problems in patient compliance (58 never screened, 34 delayed colonoscopy follow-up, and 2 inadequate bowel preparation), 43.9% (n = 116) were attributable to a limitation in the FSG procedure (97 beyond the reach of the sigmoidoscope and 19 inadequate depth of insertion on FSG), and 20.5% (n = 54) were caused by endoscopist limitation (33 missed on FSG, 21 missed at initial colonoscopy) ( P < .0001). Had colonoscopy instead of FSG been used for screening, an additional 15.6% and as many as 19.0% of cancers may have been screening-detected. Limitations These estimates are reasonable approximations, but biological variability precludes precise determinations. Conclusions Prevalent nondetected cancers were more often attributable to problems with patient compliance or limitations in the FSG procedure than to missed lesions. Colonoscopy instead of FSG could have moderately increased the detection of cancer via screening.
Background Colonoscopy may be less efficacious in reducing colorectal cancer mortality in the proximal compared with the distal colon. A greater likelihood for missed and recurrent adenomas in the ...proximal colon may contribute to this phenomenon. Objective To examine whether a proximal adenoma is associated with the risk and location of missed and recurrent adenomas. Design Prospective. Setting Polyp Prevention Trial. Participants A total of 1864 patients with an adenoma at baseline underwent a follow-up colonoscopy 4 years later (adenoma recurrence). Of these, 1731 underwent a clearing colonoscopy 1 year after the baseline examination (missed adenoma). Main Outcome Measurements Association of baseline adenoma location with the risk and location of adenomas found at colonoscopy performed 1 year and 4 years later. Results At the year 1 colonoscopy, 598 patients (34.6%) had an adenoma (missed adenoma). Compared with those with a distal-only adenoma at baseline, patients with a proximal-only adenoma at baseline were more likely to have any missed adenomas (relative risk RR 1.28; 95% CI, 1.09-1.49) and a proximal-only missed adenoma (RR 2.05; 95% CI, 1.49-2.80). At the year 4 colonoscopy, 733 patients (39.3%) had adenoma recurrence. Patients with a baseline proximal-only adenoma were more likely to have any adenoma recurrence (RR 1.14; 95% CI, 1.00-1.31) and a proximal-only adenoma recurrence (RR 1.52; 95% CI, 1.15-2.02). Sensitivity analyses involving missed adenomas did not materially affect the risk or location of recurrent adenomas at year 4 colonoscopy. Limitation Lesions may still be missed on repeated colonoscopies. Conclusions Missed and recurrent adenomas are more likely to be in the proximal colon.
Background It is unclear whether the higher burden from colorectal cancer among blacks is due to an increased biological susceptibility. Objective To determine whether non-Hispanic blacks (blacks) ...have a higher risk of adenoma recurrence than non-Hispanic whites (whites) after removal of colorectal adenoma. Design Secondary analysis of the Polyp Prevention Trial (PPT) data. Setting United States. Patients Patients were 1668 self-identified whites and 153 blacks who completed the 4-year trial. Of these, 688 whites and 55 blacks enrolled in a posttrial, passive Polyp Prevention Trial Continued Follow-up Study (PPT-CFS) and underwent another colonoscopy. Main Outcome Measurements Recurrence and location of the adenoma and advanced adenoma by race-ethnicity during PPT and cumulative recurrence over a mean follow-up of 8.3 years (range, 4.9-12.4 years) among PPT-CFS enrollees. Results Blacks had similar risk of recurrence of adenoma (39.2% vs 39.4%; incidence risk ratio RR = .98; 95% CI, .80-1.20) and advanced adenoma (8.5% vs 6.4%; RR = 1.18; 95% CI, .68-2.05) as whites at the end of PPT. Recurrence risk did not differ by colon subsite. Among PPT-CFS enrollees, the cumulative recurrence rate over a maximal follow-up period of 12 years was similar for blacks and whites for adenoma (67.3% vs 67.0%; RR = 1.01; 95% CI, .84-1.21) and advanced adenoma (14.5% vs 16.9%; RR = 1.03; 95% CI, .60-1.79). Limitation There were few blacks in the long-term follow-up study. Conclusions Adenoma and advanced adenoma recurrence did not differ by race. Our study does not support more frequent surveillance colonoscopies for blacks with a personal history of adenoma as an intervention to reduce colorectal cancer disparity.
Background Despite regular colonoscopy, interval colorectal cancer (CRC) may occur. Long-term studies examining CRC rates in patients with previous colonoscopy are lacking. Objective We examined the ...rate of interval CRC in the Polyp Prevention Trial Continued Follow-up Study (PPT-CFS), an observational study of PPT participants that began after the PPT ended. Design Prospective. Setting A national U.S. community-based polyp prevention trial. Main Outcome Measurements Medical records of patients with CRC were collected, reviewed, and abstracted in a standardized fashion. Results Among 2079 PPT participants, 1297 (62.4%) agreed to participate in the PPT-CFS. They were followed for a median of 6.2 years after 4.3 years of median follow-up in the main PPT. Nine cases of CRC were diagnosed over 7626 person-years of observation (PYO), for an incidence rate of 1.2/1000 PYO. The ratio of CRCs observed compared with that expected by Surveillance, Epidemiology, and End Results was 0.64 (95% CI, 0.28-1.06). Including all CRCs (N = 22) since the beginning of the PPT, the observed compared with expected rate by Surveillance, Epidemiology, and End Results was 0.74 (95% CI, 0.47-1.05). Of patients in whom CRC developed in the PPT-CFS, 78% had a history of an advanced adenoma compared with only 43% of patients who remained cancer free ( P = .04). Limitation A relatively small number of interval cancers were detected. Conclusions Despite frequent colonoscopy during the PPT, in the years after the trial, there was a persistent ongoing risk of cancer. Subjects with a history of advanced adenoma are at increased risk of subsequent cancer and should be followed closely with continued surveillance.
Background The adenoma detection rate (ADR) is a validated and widely used measure of colonoscopy quality. There is uncertainty in the published literature as to which colonoscopy examinations should ...be excluded when measuring a physician’s ADR. Objective To examine the impact of varying the colonoscopy exclusion criteria on physician ADR. Design We applied different exclusion criteria used in 30 previous studies to a dataset of endoscopy and pathology reports. Under each exclusion criterion, we calculated physician ADR. Setting A private practice colonoscopy center affiliated with the University of Illinois College of Medicine. Patients Data on 20,040 colonoscopy examinations performed by 11 gastroenterologists from July 2009 to May 2013 and associated pathology notes. Main Outcome Measurements ADRs across all colonoscopy examinations, each physician’s ADR, and ADR ranking. Results There were 28 different exclusion criteria used when measuring the ADR. Each study used a different combination of these exclusion criteria. The proportion of all colonoscopy examinations in the dataset excluded under these combinations of exclusion criteria ranged from 0% to 92.2%. The mean ADR across all colonoscopy examinations was 39.1%. The change in mean ADR after applying the 28 exclusion criteria ranged from −5.5 to +3.0 percentage points. However, the exclusion criteria affected each physician’s ADR relatively equally, and therefore physicians’ rankings via the ADR were stable. Limitations ADR assessment was limited to a single private endoscopy center. Conclusion There is wide variation in the exclusion criteria used when measuring the ADR. Although these exclusion criteria can affect overall ADRs, the relative rankings of physicians by ADR were stable. A consensus definition of which exclusion criteria are applied when measuring ADR is needed.
Background Colonoscopy is the predominant method for colorectal cancer screening in the United States. Previous studies have documented variation across physicians in colonoscopy quality as measured ...by the adenoma detection rate (ADR). ADR is the primary quality measure of colonoscopy examinations and an indicator of the likelihood of subsequent colorectal cancer. There is interest in mechanisms to improve the ADR. In Central Illinois, a local employer and a quality improvement organization partnered to publically report physician colonoscopy quality. Objective We assessed whether this initiative was associated with an improvement in the ADR. Design We compared ADRs before and after public reporting at a private practice endoscopy center with 11 gastroenterologists in Peoria, Illinois, who participated in the initiative. To generate the ADR, colonoscopy and pathology reports from examinations performed over 4 years at the endoscopy center were analyzed by using previously validated natural language processing software. Setting A central Illinois endoscopy center. Results The ADR in the pre-public reporting period was 34.3% and 39.2% in the post-public reporting period (an increase of 4.9%, P < .001). The increase in the right-sided ADR was 5.1% ( P < .01), whereas the increase in the left-sided ADR was 2.1% ( P < .05). The increase in the ADR was 7.8% for screening colonoscopies ( P < 0.05) and 3.5% for nonscreening colonoscopies ( P < .05). All but 1 physician’s ADR increased (range −2.7% to 10.5%). There was no statistically significant change in the advanced ADR (increase of 0.8%, P = .22). Limitations There was no concurrent control group to assess whether the increased ADR was due to a secular trend. Conclusion A public reporting initiative on colonoscopy quality was associated with an increase in ADR.
Background Aberrant crypt foci (ACF) have emerged as a putative precursor to colorectal adenoma, with potential use as a biomarker of colorectal cancer. However, there are wide differences in ACF ...prevalence, dysplasia, and histologic confirmation rates across studies. These differences may, in part, be because of variability in identification of endoscopic criteria. Objective To systematically evaluate the accuracy and reliability of various endoscopic criteria used to identify ACF when using magnification chromoendoscopy (MCE). Design Images obtained via MCE were shown to participating endoscopists who diagnosed them as ACF or not and who assessed them for the endoscopic characteristics used to identify ACF in the literature. Main Outcome Measurements The predictive ability of the endoscopic criteria (crypt number, staining, margin, crypt size, epithelial thickness, and lumen shape) for histologic confirmation of ACF, and their reliability across endoscopists. The accuracy of the examiners in identifying ACF that were histologically confirmed was also assessed. Results The interrater agreement rate for all except one of the endoscopic criteria (crypt number) was low and did not improve with training. None of the criteria could significantly predict histologic confirmation of ACF. Despite training exercises, accuracy of endoscopists to correctly identify a histologically proven ACF remained low. Limitations Still images with ×40 optical magnification were analyzed rather than real-time endoscopy. All ACF samples were hyperplastic; none were dysplastic. Conclusions No endoscopic criteria evaluated by our study predicted histologic confirmation of ACF. MCE had low accuracy and poor reliability.
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