Screening for prostate cancer and subsequent treatment is of unknown benefit but carries known treatment related morbidity and mortality risks. The recent enthusiasm for screening in the United ...States contrasts sharply with the more cautious attitudes of the European and Canadian medical communities. Current data from screening series without randomization and controls are inadequate to determine screening benefit. The prostate, lung, colorectal and ovarian cancer (randomized, controlled) screening trial of the National Cancer Institute, to include 74,000 men (and 74,000 women) 60 to 74 years old, has a design power of 90% to determine a 20% reduction of prostate cancer mortality from a baseline and 3 subsequent annual screens using prostate specific antigen and digital rectal examination. Randomization of participants into this trial began on November 16, 1993. Ten screening centers nationwide, a coordinating center, a laboratory and a biorepository are participating under contract.
CONTEXT: The necessary frequency of endoscopic colorectal cancer screening after a negative examination is uncertain. OBJECTIVE: To examine the yield of adenomas and cancer in the distal colon found ...by repeat flexible sigmoidoscopy (FSG) 3 years after a negative examination. DESIGN, SETTING, AND PARTICIPANTS: Participants were drawn from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO), a randomized, controlled community-based study of cancer screening. The mean (SD) age was 65.7 (4.0) years at study entry (1993-1995) and 61.6% were men. Individuals underwent screening FSG at baseline and at 3 years as part of the protocol and were referred to their personal physicians for further evaluation of screen-detected abnormalities. Results from subsequent diagnostic evaluations were tracked in a standardized fashion. Of 11 583 eligible for repeat screening FSG 3 years after an initial negative examination, 9317 (80.4%) returned. MAIN OUTCOME MEASURES: Polyp or mass detection in distal colon at year 3 repeat FSG; incidence of adenoma or cancer in distal colon at year 3 examination; determination of reason for detection (increased depth of insertion or improved preparation at the year 3 examination or detection in a previously examined area). RESULTS: A total of 1292 returning participants (13.9%) had a polyp or mass detected by FSG 3 years after the initial examination. In the distal colon, 3.1% (292/9317) were found to have an adenoma or cancer. The incidence of advanced adenoma (n = 72) or cancer (n = 6) in the distal colon was 78 (0.8%) of 9317. Of individuals with advanced distal adenomas detected at the year 3 examination, 80.6% (58/72) had lesions found in a portion of the colon that had been adequately examined at the initial sigmoidoscopy. CONCLUSIONS: Repeat FSG 3 years after a negative examination will detect advanced adenomas and distal colon cancer. Although the overall percentage with detected abnormalities is modest, these data raise concern about the impact of a prolonged screening interval after a negative examination.
The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial is enrolling 148,000 men and women ages 55–74 at ten sreening centers nationwide with balanced randomization to intervention ...and control arms. For prostate cancer, men receive a digital rectal examination and a blood test for prostate-specific antigen. For lung cancer, men and women receive a posteroanterior view chest X-ray. For colorectal cancer, men and women undergo a 60-cm flexible sigmoidoscopy. For ovarian cancer, women receive a blood test for the CA125 tumor marker and transvaginal ultrasound. Members of the control arm continue with their usual care. Follow-up in both groups will continue for at least 13 years from randomization to assess health status and cause of death. The primary endpoint is mortality from the four PLCO cancers, which accounts for about 53% of all cancer deaths in men and 41% of cancer deaths in women in the United States each year. Blood specimens are collected from screened participants, buccal cell DNA from controls, and histology slides from cases; these are maintained in a biorepository. Participants complete a baseline questionnaire (covering health status and risk factors) and a dietary questionnaire. More than 12,000 participants were enrolled in the pilot phase (concluded in September 1994). Changes in the eligibility criteria followed. As of April 2000, enrollment exceeded 144,500. Data are scanned into designated on-site computers for uploading by participant identification number to the coordinating center for quality checks, archival storage, and preparation of analysis datasets for use by the National Cancer Institute (NCI). Scientific direction is provided by NCI scientists, trial investigators, external consultants, and an independent data safety and monitoring board. Performance and data quality are monitored via data edits, site visits, random record audits, and teleconferences. The PLCO trial is formally endorsed by the American Cancer Society and has been ranked by the American Urological Association as one of the most important prostate cancer studies being conducted. Special efforts to enroll black participants are cosponsored by the U.S. Centers for Disease Control and Prevention.
To test whether annual screening with transvaginal ultrasonography and CA 125 reduces ovarian cancer mortality.
Data from the first four annual screens, denoted T0-T3, are reported. A CA 125 value at ...or above 35 units/mL or an abnormality on transvaginal ultrasonography was considered a positive screen. Diagnostic follow-up of positive screens was performed at the discretion of participants' physicians. Diagnostic procedures and cancers were tracked and verified through medical records.
Among 34,261 screening arm women without prior oophorectomy, compliance with screening ranged from 83.1% (T0) to 77.6% (T3). Screen positivity rates declined slightly with transvaginal ultrasonography, from 4.6 at T0 to 2.9-3.4 at T1-T3; CA 125 positivity rates (range 1.4-1.8%) showed no time trend. Eighty-nine invasive ovarian or peritoneal cancers were diagnosed; 60 were screen detected. The positive predictive value (PPV) and cancer yield per 10,000 women screened on the combination of tests were similar across screening rounds (range 1.0-1.3% for PPV and 4.7-6.2 for yield); however, the biopsy (surgery) rate among screen positives decreased from 34% at T0 to 15-20% at T1-T3. The overall ratio of surgeries to screen-detected cancers was 19.5:1. Seventy-two percent of screen-detected cases were late stage (III/IV).
Through four screening rounds, the ratio of surgeries to screen-detected cancers was high, and most cases were late stage. However, the effect of screening on mortality is as yet unknown.
ClinicalTrials.gov, www.clinicaltrials.gov, NCT00002540
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The development of low-dose spiral computed tomography (CT) has rekindled hope that effective lung cancer screening might yet be found. Screening is justified when there is evidence that it will ...extend lives at reasonable cost and acceptable levels of risk. A screening test should detect all extant cancers while avoiding unnecessary workups. Thus optimal screening modalities have both high sensitivity and specificity. Due to the present state of technology, radiologists must opt to increase sensitivity and rely on follow-up diagnostic procedures to rule out the incurred false positives. There is evidence in published reports that computer-aided diagnosis technology may help radiologists alter the benefit-cost calculus of CT sensitivity and specificity in lung cancer screening protocols. This review will provide insight into the current discussion of the effectiveness of lung cancer screening and assesses the potential of state-of-the-art computer-aided design developments.
Prostate volume correlates both with prostate-specific antigen (PSA) values and with the presence of benign prostatic hyperplasia (BPH). Here we examine the relationship between prostate volume and ...PSA level in a large, geographically diverse sample of men undergoing prostate cancer screening.
We followed 35,323 men enrolled in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. Each man was screened with digital rectal examination (DRE) and PSA levels for up to 4 years. Prostate volume was estimated by DRE performed by trained examiners at the PLCO sites. Linear and logistic regression was used to assess the effect of prostate volume and age on PSA levels. Regression coefficients were adjusted for the effect of prostate volume measurement error.
Prostate volume estimated by DRE showed considerable measurement error. Averaging volume over screening visits and accounting for examiner bias greatly reduced this error. Linear regression analysis showed a slope of 0.030/cm
3 of log PSA on prostate volume when correcting for measurement error (95% confidence interval CI, 0.029 to 0.031). Age was independently associated with (log) PSA, with a slope of 0.022 per year. Logistic regression analysis of the risk of having an elevated PSA value (exceeding 4 ng/mL) showed an odds ratio of 1.9 (95% CI, 1.8 to 2.0) associated with a 10 cm
3 increase in prostate volume. The correlation of log PSA and prostate volume was 0.37. Prostate volume was not correlated with body mass index and showed weak correlation (
r = 0.14) with age.
Prostate volume and age are independently associated with increased PSA levels in a population of men undergoing screening.
The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, which is randomizing 74,000 screening arm participants (37,000 men, 37,000 women; ages 55–74) and an equal number of nonscreened ...controls, is a unique setting for the investigation of the etiology of cancer and other diseases and for the evaluation of potential molecular markers of early disease. At entry,b aseline information is collected by questionnaire on dietary intake, tobacco and alcohol use, reproductive history (for women), family history of cancer, use of selected drugs, and other selected risk factors. Blood samples collected at the baseline screening exam are aliquoted to serum, plasma, red blood cell, and buffy coat fractions. At the next two annual screening visits, serum samples are collected. At the third annual reexamination, cryopreserved whole blood is obtained, in addition to serum, plasma, red blood cell, and buffy coat fractions. At the fourth and fifth years, serum, plasma, and buffy coat are collected. All blood samples are shipped to a central repository for long-term storage at −70°C. Dietary questionnaires and buccal cells for DNA analysis are obtained from nonscreened controls. Cancer cases are identified through annual follow-up questionnaires, and all deaths are identified through vital status tracing mechanisms. Procedures are being developed to obtain archival pathologic material for selected cases of cancer and related diseases. Initial investigations are focusing on the etiology of colorectal cancer and on the operative characteristics of tests for the early detection of colorectal and prostate cancer.
OBJECTIVE
To determine patterns of repeat prostate biopsy in a cohort of men undergoing prostate cancer screening who have a negative initial biopsy.
SUBJECTS AND METHODS
The Prostate, Colorectal, ...Lung, and Ovarian (PLCO) cancer screening trial is an ongoing study the prostate component of which consists of six annual screens with measurements of prostate‐specific antigen (PSA) level and a digital rectal examination (DRE). The diagnostic follow‐up of positive screening results is done by the subject’s healthcare provider outside the purview of the PLCO. We analysed the experience of repeat biopsy in men in the PLCO with an initial negative biopsy. Men were divided by indication for initial biopsy into those with suspicious PSA levels and those with suspicious DRE findings.
RESULTS
The probability of having a repeat biopsy within 3 years of initial biopsy was 43% for 1736 men with suspicious PSA levels and 13% for 1025 men with suspicious DRE findings. Rates of third and fourth biopsy after a previous negative biopsy were similar to the initial repeat biopsy rate in PSA‐positive men. Most men had a repeat biopsy only after having an additional round of screening. The PSA level and PSA velocity determined after initial biopsy were independent risk factors for a repeat biopsy, both in PSA‐positive and DRE‐positive men. High‐grade prostatic intraepithelial neoplasia was a risk factor for repeat biopsy before any repeat PSA or DRE testing.
CONCLUSION
The experience of this cohort should be generally representative of patterns of care for repeat biopsy in men undergoing periodic screening. These data can provide context to the debate over optimum practices for repeat biopsy.
Annual screening with PSA, although of unproven benefit, is currently used for prostate cancer early detection. A large fraction of screened men have low (less than 2 ng/ml) initial PSA. The yield ...over time of positive PSA screens (ie more than 4 ng/ml) in these men has not been well characterized in large cohorts in the United States.
Men in the screening arm of the PLCO received baseline PSA and annual tests for 5 years. 30,495 of these men had baseline PSA 4 ng/ml or less. We estimated the cumulative probability of converting to PSA greater than 4 at years 1 through 5 as a function of baseline PSA.
Among men with baseline PSA less than 1 ng/ml, 1.5% converted by year 5 (95% CI 1.2-1.7). Among men with baseline PSA of 1.0 to 1.99 ng/ml, 1.2% (95% CI 0.9-1.3) and 7.4% (95% CI 6.8-8.1) converted by year 1 and 5, respectively. A total of 33.5% and 79% of men with initial PSA of 2.0 to 2.99 and 3.0 to 4.0, respectively, converted by year 5. Of men with baseline PSA less than 1 ng/ml converting to PSA more than 4 ng/ml, 8% were diagnosed with cancer within 2 years of conversion. About 10% of men with baseline PSA less than 1 ng/ml and negative baseline DRE had a positive DRE within 3 years.
For men choosing PSA screening, screening every 5 years for baseline PSA less than 1 ng/ml and every 2 years for PSA 1 to 2 ng/ml could result in a 50% reduction in PSA tests and in less than 1.5% of men missing earlier positive screens, but with an unknown effect on prostate cancer mortality.
To critically evaluate the evidence for recommending the screening of asymptomatic men for prostate cancer with a blood test to detect a prostate-specific antigen (PSA).
Relevant articles on ...screening for prostate cancer were identified from MEDLINE searches, from the authors' files, and from the bibliographies of identified articles.
In the absence of controlled prospective trials, the studies are primarily retrospective and contain information about the sensitivity, specificity, and predictive values of tests used to screen for prostate cancer; the natural history of untreated prostate cancer; the morbidity, mortality, and costs of definitive treatment; and reviews of screening study biases.
Potential treatment-related mortality and costs that could be incurred by screening were estimated using defined assumptions.
Although screening for prostate cancer has the potential to save lives, because of possible overdiagnosis, screening and subsequent therapy could actually have a net unfavorable effect on mortality or quality of life or both. Given the performance characteristics of the test, widespread screening efforts would probably cost billions of dollars.
The net benefit from widespread screening is unclear. A randomized prospective study of the effect of screening on prostate cancer mortality has therefore been initiated by the National Cancer Institute.
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