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Flexible sigmoidoscopy in the randomized prostate, lung, colorectal, and ovarian (PLCO) cancer screening trial: added yield from a second screening examination.

ABSTRACT: BACKGROUND:Among randomized trials evaluating flexible sigmoidoscopy (FSG) for its effect on colorectal cancer mortality, only the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial screened its participants more than one time. We report outcomes from the PLCO screening FSG program and evaluate the increased yield produced by a second FSG. METHODS:Participants were screened by 60-cm FSG in 10 regional screening centers at study entry and 3 or 5 years later, depending on the time of random assignment. Results from subsequent diagnostic intervention were tracked and recorded in a standardized fashion, and outcomes were compared according to sex and age. The protocol discouraged repeat FSG in persons with colorectal cancer or adenoma diagnosed after the initial FSG. RESULTS:Of 77?447 enrollees, 67?073 (86.6%) had at least one FSG and 39?443 (50.9%) had two FSGs. Diagnostic intervention occurred in 74.9% after a positive first FSG and in 78.7% after a positive repeat FSG. The second FSG increased the screening yield by 32%: Colorectal cancer or advanced adenoma was detected in 37.8 per 1000 persons after first screening and in 49.8 per 1000 persons after all screenings. The second FSG increased the yield of cancer or advanced adenoma by 26% in women and by 34% in men. Of 223 subjects who received a diagnosis of colorectal carcinoma within 1 year of a positive FSG, 64.6% had stage I and 17.5% had stage II disease. CONCLUSIONS:Repeat FSG increased the detection of colorectal cancer or advanced adenoma in women by one-fourth and in men by one-third. Screen-detected carcinomas were early stage (stage I or II) in greater than 80% of screened persons. Colorectal cancer mortality data from the PLCO, as the definitive endpoint, will follow in later publications.

SUBMITTER: Weissfeld JL

PROVIDER: S-EPMC3283538 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

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Flexible sigmoidoscopy in the randomized prostate, lung, colorectal, and ovarian (PLCO) cancer screening trial: added yield from a second screening examination.

Weissfeld Joel L JL Schoen Robert E RE Pinsky Paul F PF Bresalier Robert S RS Doria-Rose V Paul VP Laiyemo Adeyinka O AO Church Timothy T Yokochi Lance A LA Yurgalevitch Susan S Rathmell Joshua J Andriole Gerald L GL Buys Saundra S Crawford E David ED Fouad Mona M Isaacs Claudine C Lamerato Lois L Reding Douglas D Prorok Philip C PC Berg Christine D CD

Journal of the National Cancer Institute 20120131 4

<h4>Background</h4>Among randomized trials evaluating flexible sigmoidoscopy (FSG) for its effect on colorectal cancer mortality, only the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial screened its participants more than one time. We report outcomes from the PLCO screening FSG program and evaluate the increased yield produced by a second FSG.<h4>Methods</h4>Participants were screened by 60-cm FSG in 10 regional screening centers at study entry and 3 or 5 years later, depe ...[more]

PMID: 22298838

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Project description:BACKGROUND:Screening for colorectal cancer (CRC) with flexible sigmoidoscopy (FS) has been shown to reduce CRC mortality. The current study examined whether the observed mortality reduction was due primarily to the prevention of incident CRC via removal of adenomatous polyps or to the early detection of cancer and improved survival. METHODS:The Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial randomized 154,900 men and women aged 55 to 74 years. Individuals underwent FS screening at baseline and at 3 or 5 years versus usual care. CRC-specific survival was analyzed using Kaplan-Meier curves and proportional hazards modeling. The authors estimated the percentage of CRC deaths averted by early detection versus primary prevention using a model that applied intervention arm survival rates to CRC cases in the usual-care arm and vice versa. RESULTS:A total of 1008 cases of CRC in the intervention arm and 1291 cases of CRC in the usual-care arm were observed. Through 13 years of follow-up, there was no significant difference noted between the trial arms with regard to CRC-specific survival for all CRC (68% in the intervention arm vs 65% in the usual-care arm; P =.16) or proximal CRC (68% vs 62%, respectively; P = .11) cases; however, survival in distal CRC cases was found to be higher in the intervention arm compared with the usual-care arm (77% vs 66%; P<.0001). Within each arm, symptom-detected cases had significantly worse survival compared with screen-detected cases. Overall, approximately 29% to 35% of averted CRC deaths were estimated to be due to early detection and 65% to 71% were estimated to be due to primary prevention. CONCLUSIONS:CRC-specific survival was similar across arms in the PLCO trial, suggesting a limited role for early detection in preventing CRC deaths. Modeling suggested that approximately two-thirds of avoided deaths were due to primary prevention. Future CRC screening guidelines should emphasize primary prevention via the identification and removal of precursor lesions. Cancer 2017;123:4815-22. © 2017 American Cancer Society.

Project description:BackgroundScreening flexible sigmoidoscopy reduces incidence and mortality of colorectal cancer. Previously reported results from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) screening trial had a median follow-up of 12 years. Whether the benefit is sustained over the long term and remains so in both sexes and all age groups is uncertain. We report long-term results after an additional 5 years of follow-up.MethodsParticipants in the PLCO trial were recruited from the general population in the catchment areas of ten screening centres across the USA, without previous diagnosis of a prostate, lung, colorectal, or ovarian cancer or current cancer treatment. From 1993 to 2001, participants aged 55-74 years were randomly assigned to usual care or flexible sigmoidoscopy at baseline and again at 3 years or 5 years. Randomisation was done within blocks and stratified by centre, age, and sex. The primary endpoint was cause-specific mortality and secondary endpoints included incidence and tumour staging; cause of death was determined without knowledge of study arm. In this analysis, we assessed incidence and mortality rates overall, by time-period, and by combinations of sex, age at baseline (55-64 years/65-74 years), location (distal/proximal), and stage, on an intent-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT00002540.FindingsAfter a median follow-up of 15·8 years (IQR 13·2-18·0) for incidence and 16·8 years (14·4-18·9) for mortality, the incidence of colorectal cancer was significantly lower in the intervention arm (1461 cases; 12·55 per 10 000 person-years) than with usual care (1761 cases; 15·33 per 10 000 person-years; relative risk [RR] 0·82, 95% CI 0·76-0·88). Similarly, mortality was lower in the intervention arm (417 deaths; 3·37 per 10 000 person-years) than the usual care arm (549; 4·48 per 10 000 person-years; RR 0·75, 95% CI 0·66-0·85). The reduction in mortality was limited to the distal colon, with no significant effect in the proximal colon. Reductions in incidence were significantly larger in men than women (pinteraction=0·04) and reductions in mortality were significantly larger in the older age group (65-74 years vs 55-64 years at baseline; pinteraction=0·01).InterpretationReductions in colorectal cancer incidence and mortality from flexible sigmoidoscopy screening are sustained over the long term. Differences by sex and age should be examined in other ongoing trials of colorectal cancer screening to help clarify if different screening strategies would achieve greater risk reduction.FundingExtended follow-up was funded under NIH contract HHSN261201600007I.

Project description:BackgroundThe 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.MethodsA 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.ResultsCompliance 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 (P(trend) < .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.ConclusionsThe 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.

Project description:BackgroundColorectal cancer is the third most common cancer worldwide. Previous analyses have only reported follow-up after flexible sigmoidoscopy for a maximum of 12 years. We aimed to examine colorectal cancer incidence and mortality after a single flexible sigmoidoscopy screening and 17 years of follow-up.MethodsIn this multicentre randomised trial (UK Flexible Sigmoidoscopy Screening Trial), done between Nov 14, 1994, and March 30, 1999, 170 432 eligible men and women, who had indicated on a previous questionnaire that they would probably attend screening if invited, were randomly assigned (1:2) to an intervention group (offered flexible sigmoidoscopy screening) or a control group (not contacted). Randomisation was done centrally in blocks of 12, and stratified by trial centre, general practice, and household type. The nature of the intervention did not allow the staff to be masked to arm of the trial; however, randomisation was done in batches so that the control group and participants not yet randomised were unaware of their allocation status. The primary outcomes were incidence and mortality of colorectal cancer. Hazard ratios (HRs) and 95% CIs for colorectal cancer incidence and mortality were estimated for intention-to-treat and per-protocol analyses. The trial is registered with ISRCTN, number 28352761.FindingsOur cohort analysis included 170 034 people: 112 936 in the control group and 57 098 in the intervention group, 40 621 (71%) of whom were screened and 16 477 (29%) were not screened. During screening and a median of 17·1 years' follow-up, colorectal cancer was diagnosed in 1230 individuals in the intervention group and 3253 in the control group, and 353 individuals in the intervention group versus 996 individuals in the control group died from colorectal cancer. In intention-to-treat analyses, colorectal cancer incidence was reduced by 26% (HR 0·74 [95% CI 0·70-0·80]; p<0·0001) in the intervention group versus the control group and colorectal cancer mortality was reduced by 30% (0·70 [0·62-0·79]; p<0·0001) in the intervention group versus the control group. In per-protocol analyses, adjusted for non-compliance, colorectal cancer incidence and mortality were 35% (HR 0·65 [95% CI 0·59-0·71]) and 41% (0·59 [0·49-0·70]) lower in the screened group.InterpretationA single flexible sigmoidoscopy continues to provide substantial protection from colorectal cancer diagnosis and death, with protection lasting at least 17 years.FundingNational Institute for Health Research Efficacy and Mechanism Evaluation.

Project description:BACKGROUND:The benefits of endoscopic testing for colorectal-cancer screening are uncertain. We evaluated the effect of screening with flexible sigmoidoscopy on colorectal-cancer incidence and mortality. METHODS:From 1993 through 2001, we randomly assigned 154,900 men and women 55 to 74 years of age either to screening with flexible sigmoidoscopy, with a repeat screening at 3 or 5 years, or to usual care. Cases of colorectal cancer and deaths from the disease were ascertained. RESULTS:Of the 77,445 participants randomly assigned to screening (intervention group), 83.5% underwent baseline flexible sigmoidoscopy and 54.0% were screened at 3 or 5 years. The incidence of colorectal cancer after a median follow-up of 11.9 years was 11.9 cases per 10,000 person-years in the intervention group (1012 cases), as compared with 15.2 cases per 10,000 person-years in the usual-care group (1287 cases), which represents a 21% reduction (relative risk, 0.79; 95% confidence interval [CI], 0.72 to 0.85; P<0.001). Significant reductions were observed in the incidence of both distal colorectal cancer (479 cases in the intervention group vs. 669 cases in the usual-care group; relative risk, 0.71; 95% CI, 0.64 to 0.80; P<0.001) and proximal colorectal cancer (512 cases vs. 595 cases; relative risk, 0.86; 95% CI, 0.76 to 0.97; P=0.01). There were 2.9 deaths from colorectal cancer per 10,000 person-years in the intervention group (252 deaths), as compared with 3.9 per 10,000 person-years in the usual-care group (341 deaths), which represents a 26% reduction (relative risk, 0.74; 95% CI, 0.63 to 0.87; P<0.001). Mortality from distal colorectal cancer was reduced by 50% (87 deaths in the intervention group vs. 175 in the usual-care group; relative risk, 0.50; 95% CI, 0.38 to 0.64; P<0.001); mortality from proximal colorectal cancer was unaffected (143 and 147 deaths, respectively; relative risk, 0.97; 95% CI, 0.77 to 1.22; P=0.81). CONCLUSIONS:Screening with flexible sigmoidoscopy was associated with a significant decrease in colorectal-cancer incidence (in both the distal and proximal colon) and mortality (distal colon only). (Funded by the National Cancer Institute; PLCO ClinicalTrials.gov number, NCT00002540.).

Dataset Information

Flexible sigmoidoscopy in the randomized prostate, lung, colorectal, and ovarian (PLCO) cancer screening trial: added yield from a second screening examination.

Publications

Flexible sigmoidoscopy in the randomized prostate, lung, colorectal, and ovarian (PLCO) cancer screening trial: added yield from a second screening examination.

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