After nearly 12 years of follow-up, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial has shown that screening with flexible sigmoidoscopy reduces colorectal-cancer incidence by 21% ...and mortality by 26%.
Colorectal cancer is the second leading cause of cancer-related deaths in the United States.
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Colorectal-cancer mortality
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and incidence
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are reduced with screening by means of fecal occult-blood testing. Endoscopic screening with flexible sigmoidoscopy or colonoscopy is more sensitive than fecal testing for the detection of adenomatous polyps, the precursor lesions of colorectal cancer.
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Three European randomized trials of flexible sigmoidoscopy have been performed.
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In the United Kingdom, one-time screening with flexible sigmoidoscopy significantly reduced the incidence of colorectal cancer (by 23%) and associated mortality (by 31%).
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In Italy, an 18% reduction in incidence and a nonsignificant 22% . . .
CONTEXT Screening for ovarian cancer with cancer antigen 125 (CA-125) and transvaginal ultrasound has an unknown effect on mortality. OBJECTIVE To evaluate the effect of screening for ovarian cancer ...on mortality in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. DESIGN, SETTING, AND PARTICIPANTS Randomized controlled trial of 78 216 women aged 55 to 74 years assigned to undergo either annual screening (n = 39 105) or usual care (n = 39 111) at 10 screening centers across the United States between November 1993 and July 2001. INTERVENTION The intervention group was offered annual screening with CA-125 for 6 years and transvaginal ultrasound for 4 years. Participants and their health care practitioners received the screening test results and managed evaluation of abnormal results. The usual care group was not offered annual screening with CA-125 for 6 years or transvaginal ultrasound but received their usual medical care. Participants were followed up for a maximum of 13 years (median range, 12.4 years 10.9-13.0 years) for cancer diagnoses and death until February 28, 2010. MAIN OUTCOME MEASURES Mortality from ovarian cancer, including primary peritoneal and fallopian tube cancers. Secondary outcomes included ovarian cancer incidence and complications associated with screening examinations and diagnostic procedures. RESULTS Ovarian cancer was diagnosed in 212 women (5.7 per 10 000 person-years) in the intervention group and 176 (4.7 per 10 000 person-years) in the usual care group (rate ratio RR, 1.21; 95% confidence interval CI, 0.99-1.48). There were 118 deaths caused by ovarian cancer (3.1 per 10 000 person-years) in the intervention group and 100 deaths (2.6 per 10 000 person-years) in the usual care group (mortality RR, 1.18; 95% CI, 0.82-1.71). Of 3285 women with false-positive results, 1080 underwent surgical follow-up; of whom, 163 women experienced at least 1 serious complication (15%). There were 2924 deaths due to other causes (excluding ovarian, colorectal, and lung cancer) (76.6 per 10 000 person-years) in the intervention group and 2914 deaths (76.2 per 10 000 person-years) in the usual care group (RR, 1.01; 95% CI, 0.96-1.06). CONCLUSIONS Among women in the general US population, simultaneous screening with CA-125 and transvaginal ultrasound compared with usual care did not reduce ovarian cancer mortality. Diagnostic evaluation following a false-positive screening test result was associated with complications. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00002540
CONTEXT The effect on mortality of screening for lung cancer with modern chest radiographs is unknown. OBJECTIVE To evaluate the effect on mortality of screening for lung cancer using radiographs in ...the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. DESIGN, SETTING, AND PARTICIPANTS Randomized controlled trial that involved 154 901 participants aged 55 through 74 years, 77 445 of whom were assigned to annual screenings and 77 456 to usual care at 1 of 10 screening centers across the United States between November 1993 and July 2001. The data from a subset of eligible participants for the National Lung Screening Trial (NLST), which compared chest radiograph with spiral computed tomographic (CT) screening, were analyzed. INTERVENTION Participants in the intervention group were offered annual posteroanterior view chest radiograph for 4 years. Diagnostic follow-up of positive screening results was determined by participants and their health care practitioners. Participants in the usual care group were offered no interventions and received their usual medical care. All diagnosed cancers, deaths, and causes of death were ascertained through the earlier of 13 years of follow-up or until December 31, 2009. MAIN OUTCOME MEASURES Mortality from lung cancer. Secondary outcomes included lung cancer incidence, complications associated with diagnostic procedures, and all-cause mortality. RESULTS Screening adherence was 86.6% at baseline and 79% to 84% at years 1 through 3; the rate of screening use in the usual care group was 11%. Cumulative lung cancer incidence rates through 13 years of follow-up were 20.1 per 10 000 person-years in the intervention group and 19.2 per 10 000 person-years in the usual care group (rate ratio RR; 1.05, 95% CI, 0.98-1.12). A total of 1213 lung cancer deaths were observed in the intervention group compared with 1230 in usual care group through 13 years (mortality RR, 0.99; 95% CI, 0.87-1.22). Stage and histology were similar between the 2 groups. The RR of mortality for the subset of participants eligible for the NLST, over the same 6-year follow-up period, was 0.94 (95% CI, 0.81-1.10). CONCLUSION Annual screening with chest radiograph did not reduce lung cancer mortality compared with usual care. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00002540
Background & Aims The recommended timing of surveillance colonoscopy for individuals with adenomatous polyps is based on adenoma histology, size, and number. The burden and cost of surveillance ...colonoscopy are significant. The aim of this study was to examine the use of surveillance colonoscopy on a community-wide basis. Methods We retrospectively queried participants in the Prostate, Lung, Colorectal, and Ovarian Cancer screening trial in 9 US communities about use of surveillance colonoscopy. Subjects whose initial colonoscopy showed advanced adenoma (AA), nonadvanced adenoma (NAA), or no adenoma (NA) findings were included. Colonoscopy examinations were confirmed by reviewing colonoscopy reports. Results Of 3876 subjects selected for inquiry, 3627 (93.6%) responded. The cumulative probability of a surveillance colonoscopy within 5 years was 58.4% (n = 1342) in the AA group, 57.5% in those with ≥3 NAAs (n = 117), 46.7% in those with 1–2 NAAs (n = 905), and 26.5% (n = 1263) in subjects with NAs. Within 7 years, 33.2% of subjects with AAs received ≥2 surveillance examinations versus 26.9% for those with ≥3 NAAs, 18.2% for those with 1 or 2 NAAs, and 10.4% for those with NAs. Incomplete colonoscopy, family history of colorectal cancer, or interval adenomatous findings could explain only a minority of surveillance colonoscopy in low-risk subjects. Conclusions In community practice, there is substantial overuse of surveillance colonoscopy among low-risk subjects and underuse among subjects with AAs. Interventions to better align use of surveillance colonoscopy with risk for advanced lesions are needed.
Background & Aims Surveillance colonoscopy is recommended for subjects with a history of adenomas but there is limited information on the yield of surveillance. Methods A sample of subjects in the ...Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial with abnormal flexible sigmoidoscopy and follow-up colonoscopy were queried about subsequent surveillance colonoscopy over a 10-year period. Medical records were obtained to verify procedure dates and histologic findings. Subjects with advanced adenomas, nonadvanced adenoma, nonadenomatous polyps, and no polyps at baseline were included. Results At the first surveillance, 10.5% had advanced adenoma and 37% had any adenoma in the advanced adenoma group (n = 1057), compared with rates of 6.8% and 32% (nonadvanced adenoma: n = 765), 4.9% and 22% (nonadenomatous polyps: n = 658), and 3.1% and 16% (no polyps: n = 127) ( P < .0001, linear trend test). Mean (SD) time intervals (years) from baseline colonoscopy to first surveillance were 3.4 (2.0) for advanced adenoma, 4.3 (2.0) for nonadvanced adenoma, 4.5 (2.0) for nonadenomatous polyps, and 4.7 (2.0) for no polyps. There were no increasing (or decreasing) trends in the observed rate of advanced adenoma or any adenoma with time to the initial surveillance examination in any baseline group. Among subjects with a second surveillance examination, adenoma findings at both baseline and first surveillance influenced the rates of advanced adenoma and any adenoma at second surveillance. Conclusions Subjects with baseline advanced adenomas are more likely to have recurrent advanced adenomas at initial surveillance. The lack of association between recurrence rates and time to surveillance suggests limitations in our understanding of the biology of adenoma development.
Background The 5-year overall survival rate of lung cancer patients is approximately 15%. Most patients are diagnosed with advanced-stage disease and have shorter survival rates than patients with ...early-stage disease. Although screening for lung cancer has the potential to increase early diagnosis, it has not been shown to reduce lung cancer mortality rates. In 1993, the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was initiated specifically to determine whether screening would reduce mortality rates from PLCO cancers. Methods A total of 77 464 participants, aged 55–74 years, were randomly assigned to the intervention arm of the PLCO Cancer Screening Trial between November 8, 1993, and July 2, 2001. Participants received a baseline chest radiograph (CXR), followed by three annual single-view CXRs at the 10 US screening centers. Cancers were classified as screen detected and nonscreen detected (interval or never screened) and according to tumor histology. The positivity rates of screen-detected cancers and positive predictive values (PPVs) were calculated. Because 51.6% of the participants were current or former smokers, logistic regression analysis was performed to control for smoking status. All statistical tests were two-sided. Results Compliance with screening decreased from 86.6% at baseline to 78.9% at the last screening. Overall positivity rates were 8.9% at baseline and 6.6%–7.1% at subsequent screenings; positivity rates increased modestly with smoking risk categories (Ptrend < .001). The PPVs for all participants were 2.0% at baseline and 1.1%, 1.5%, and 2.4% at years 1, 2, and 3, respectively; PPVs in current smokers were 5.9% at baseline and 3.3%, 4.2%, and 5.6% at years 1, 2, and 3, respectively. A total of 564 lung cancers were diagnosed, of which 306 (54%) were screen-detected cancers and 87% were non–small cell lung cancers. Among non–small cell lung cancers, 59.6% of screen-detected cancers and 33.3% of interval cancers were early (I–II) stage. Conclusions The PLCO Cancer Screening Trial demonstrated the ability to recruit, retain, and screen a large population over multiple years at multiple centers. A higher proportion of screen-detected lung cancers were early stage, but a conclusion on the effectiveness of CXR screening must await final PLCO results, which are anticipated at the end of 2015.
Heterocyclic amines (HAA) are animal carcinogens that are present in meat cooked at high temperature and in tobacco smoke. These compounds require activation by cytochrome P450 1A2 (CYP1A2) and ...N-acetyltransferase-2 (NAT2) before they can damage DNA. This study tested the hypotheses that well-done meat and cigarette smoking increase the risk of adenoma, the precursor to most colorectal cancers, especially in individuals with rapid CYP1A2 and rapid NAT2 activities.
An endoscopy-based case-control study of adenoma was conducted among Caucasians, Japanese and native Hawaiians to test this hypothesis. The overall diet and consumption of well-done meat cooked by various high-temperature methods were assessed by interview in 1016 patients with a first adenoma and 1355 controls with a normal endoscopy. A caffeine test was used to assess CYP1A2 and NAT2 activities in 635 cases and 845 controls. Logistic regression was used to account for matching factors and potential confounders.
Smoking was associated with an increased risk of adenoma. Weak non-significant elevated OR were observed for the main effects of HAA intakes or NAT2 activity. However, the combined effects of HAA intakes and NAT2 activity were statistically significant. Subjects in both the upper tertiles of NAT2 activity and HAA intake were at increased risk of adenoma compared with subjects in the lower tertiles of NAT2 activity and exposure (2-amino-3,4,8-dimethylimidazo4,5-fquinoxaline intake OR 1.70, 95% CI I 1.06 to 2.75; 2-amino-3,8-dimethylimidazo4,5-fquinoxaline intake OR 1.91, 95% CI 1.16 to 3.16; and 2-amino-1-methyl-6-phenylimidazo4,5-bpyridine intake OR 2.14, 95% CI 1.31 to 3.49).
The data suggest that rapid N-acetylators with high HAA intake may be at increased risk of adenoma.
Background
The prostate component of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was undertaken to determine whether there is a reduction in prostate cancer mortality ...from screening using serum prostate-specific antigen (PSA) testing and digital rectal examination (DRE). Mortality after 7-10 years of follow-up has been reported previously. We report extended follow-up to 13 years after the trial.
Methods
A total of 76 685 men, aged 55-74 years, were enrolled at 10 screening centers between November 1993 and July 2001 and randomly assigned to the intervention (organized screening of annual PSA testing for 6 years and annual DRE for 4 years; 38 340 men) and control (usual care, which sometimes included opportunistic screening; 38 345 men) arms. Screening was completed in October 2006. All incident prostate cancers and deaths from prostate cancer through 13 years of follow-up or through December 31, 2009, were ascertained. Relative risks (RRs) were estimated as the ratio of observed rates in the intervention and control arms, and 95% confidence intervals (CIs) were calculated assuming a Poisson distribution for the number of events. Poisson regression modeling was used to examine the interactions with respect to prostate cancer mortality between trial arm and age, comorbidity status, and pretrial PSA testing. All statistical tests were two-sided.
Results
Approximately 92% of the study participants were followed to 10 years and 57% to 13 years. At 13 years, 4250 participants had been diagnosed with prostate cancer in the intervention arm compared with 3815 in the control arm. Cumulative incidence rates for prostate cancer in the intervention and control arms were 108.4 and 97.1 per 10 000 person-years, respectively, resulting in a relative increase of 12% in the intervention arm (RR = 1.12, 95% CI = 1.07 to 1.17). After 13 years of follow-up, the cumulative mortality rates from prostate cancer in the intervention and control arms were 3.7 and 3.4 deaths per 10 000 person-years, respectively, resulting in a non-statistically significant difference between the two arms (RR = 1.09, 95% CI = 0.87 to 1.36). No statistically significant interactions with respect to prostate cancer mortality were observed between trial arm and age (P
interaction = .81), pretrial PSA testing (P
interaction = .52), and comorbidity (P
interaction = .68).
Conclusions
After 13 years of follow-up, there was no evidence of a mortality benefit for organized annual screening in the PLCO trial compared with opportunistic screening, which forms part of usual care, and there was no apparent interaction with age, baseline comorbidity, or pretrial PSA testing.
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: Research on the association between fruit and vegetable intake and risk of colorectal adenoma is inconclusive. OBJECTIVE: We studied whether intake of fruit, vegetables, or their ...subgroups is associated with a lower risk of prevalent colorectal adenoma. DESIGN: In men and women (aged 55-74 y) who were screened for colorectal cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) (1993-2001), we compared 3057 cases with at least one prevalent histologically verified adenoma of the distal large bowel with 29 413 control subjects. Using a food-frequency questionnaire, we quantified intake of fruit and vegetables in the 12 mo before screening as energy-adjusted pyramid servings/d (ps/d). Adjusted odds ratios (ORs) and 95% CIs were estimated by logistic regression. RESULTS: Risk of distal adenoma was significantly lower among subjects in high (almost equal to5.7 ps/d) versus low (almost equal to1.2 ps/d) quintiles of total fruit intake (OR: 0.75; 95% CI: 0.66, 0.86, P for trend <0.001), which was not completely explained by dietary folate or fiber intake. Inverse associations between adenoma and total fruit intake were observed regardless of adenoma histopathology and multiplicity. However, the protective effect was seen only for colon and not rectal adenoma. Total vegetable intake was not significantly associated with reduced risk of adenoma. ORs for colorectal adenoma among persons with high versus low intakes of deep-yellow vegetables, dark-green vegetables, and onions and garlic were significantly related to lower risk of adenoma, although the P for trend for dark-green vegetables was not significant. CONCLUSION: Diets rich in fruit and deep-yellow vegetables, dark-green vegetables, and onions and garlic are modestly associated with reduced risk of colorectal adenoma, a precursor of colorectal cancer.
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