Assessing contamination and compliance in the prostate component of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial
Why this work is in the frame
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Bibliographic record
Abstract
BACKGROUND: Recently, the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial published 7-year complete prostate cancer mortality results, which showed no benefit of screening with prostate specific antigen (PSA) and digital rectal examination (DRE). An issue of concern was the substantial level of 'contamination', or use of PSA and DRE in control arm men. PURPOSE: To provide a detailed description of contamination in PLCO. METHODS: Surveys inquiring about the most recent PSA and DRE use were given to a sample of control arm men throughout the screening phase of PLCO (years 0-5). A probability model was utilized to translate survey results into actual frequency counts of tests. To assess the impact of contamination, Surveillance, Epidemiology, and End RESULTS: (SEER) incidence rates from the pre-screening era (1985-1987) as well as contemporaneous rates, were applied to PLCO person-years of observation. Results Of 38,350 control arm men, 2427 were surveyed. Pre-trial screening and college education were statistically significantly associated with increased contamination rates. The estimated mean number of screening PSAs (DREs) in the control arm was 2.7 (1.1); this compares to 5.0 (3.5) in the screened arm. 1984 and 2538 prostate cancers were observed in the control and screened arms, respectively, during the screening phase. In the absence of screening, 960 and 949 would have been expected; with contemporaneous incidence rates, 1630 and 1611 were expected. LIMITATIONS: Due to the limitations of the surveys, in terms of both reach and scope, the exact level of PSA and DRE use in control arm men cannot be known. CONCLUSIONS: Use of prostate screening by control arm men was substantial, but also substantially less than in screened arm men. Detailed quantitative analyses of screening use across arms are critical for understanding current and future findings from the prostate component of PLCO.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it