Screening for Prostate Cancer in Older Patients (PLCO Screening Trial)

Exclusion Criteria: * Men who at the time of randomization are less than 55 or greater than or equal to 75 years of age * Individuals undergoing treatment for cancer at this time, excluding basal-cell and squamous-cell skin cancer * Individuals with known prior cancer of the colon, rectum, lung, prostate * This includes primary or metastatic PLCO cancers * Individuals with previous surgical removal of the entire colon, one lung, or the entire prostate * Individuals who are participating in another cancer screening or cancer primary prevention trial * Males who have taken Proscar/Propecia/finasteride in the past 6 months * NOTE: Individuals who are already enrolled in the trial when their physician prescribes finasteride are not prevented from taking this medication. As a result, these participants will continue to be screened and followed just as those participants who are not on finasteride. * NOTE: Men who are taking Tamoxifen are not excluded from any part of the PLCO Screening Trial. * Individuals who are unwilling or unable to sign the informed consent form * Males who have had more than one PSA blood test in the past three years * Individuals who have had a colonoscopy, sigmoidoscopy, or barium enema in the past three years