Methods
prostate, lung, colorectal, and ovarian cancer, Cancer
SECONDARY, CANCER
This cohort study was a secondary analysis of the PLCO Cancer Screening Trial, a large, multicenter randomized clinical trial that evaluated the efficacy of prostate, lung, colorectal, and ovarian cancer screening examinations in reducing mortality. The PLCO Cancer Screening Trial was approved by the institutional review boards of all study sites. Participants provided written informed consent for the original and ancillary studies. Additional approval for the current study was not required because data use in ancillary studies was included in the original consent and all data were deidentified. This study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology (