OBJECTIVES: I. Determine whether screening with flexible sigmoidoscopy and chest x-ray can reduce mortality from colorectal and lung cancer, respectively, in men and women aged 55-74. II. Determine whether screening with digital rectal examination (DRE) plus serum prostate-specific antigen (PSA) can reduce mortality from prostate cancer in men aged 55-74. III. Determine whether screening with CA 125 and transvaginal ultrasound can reduce mortality from ovarian cancer in women aged 55-74. IV. Assess other screening variables for each of the above interventions including sensitivity, specificity, and positive predictive value. V. Assess the incidence, stage, and survival experience of cancer cases. VI. Investigate the mortality predictive value of biologic and/or prognostic characterizations of tumor tissue as intermediate endpoints.

OUTLINE: This is a randomized study. Patients are stratified by participating center, gender, and age (55-59 vs 60-64 vs 65-69 vs 70-74). Patients are randomized to one of two treatment arms. Arm I (Control): Patients receive standard medical care. Arm II: All patients undergo an initial sigmoidoscopic examination and chest x-ray; men also undergo DRE and PSA testing and women undergo a transvaginal ultrasound and CA 125 test. A scheduling and tracking procedure is implemented to ensure regular attendance at repeat screens for subjects screened negative or for those who are designated suspicious or positive at screening but for whom subsequent diagnostic procedures do not reveal prostate, lung, colorectal, or ovarian cancer (follow-up diagnostic procedures are through their own medical care environment). Patients diagnosed via a screening test with cancer of the prostate, lung, colorectum, or ovary are referred for treatment in accordance with current accepted practice for appropriate stage of disease, patient age, and medical condition; a procedure is provided for contact with qualified medical personnel to insure appropriate therapy. DRE (men only), transvaginal ultrasound (women only), and chest x-ray are repeated annually for 3 years. Patients who have never smoked do not receive a third chest x-ray. PSA testing (men only) and CA 125 tests (women only) are repeated annually for 5 years; the sigmoidoscopic exam is repeated 5 years after the initial exam. A Periodic Survey of Health questionnaire is mailed to each participant annually for 13 years to identify all prevalent and incident cancers of the prostate, lung, colorectum, and ovary as well as all deaths that occur among both screened and control subjects during the trial.

PROJECTED ACCRUAL: A total of 74,000 women and 74,000 men (37,000 for each gender/arm) will be accrued for this study from 10 screening centers (10,000-20,000/center).

DISEASE CHARACTERISTICS: See General Eligibility Criteria

PATIENT CHARACTERISTICS: Men and women aged 55-74 with no known prior cancer of the colon, rectum, lung, prostate, or ovary No routine surveillance for a medical condition involving the above sites No participation in another cancer screening or primary prevention trial

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: No prior or concurrent finasteride for benign prostatic hypertrophy Radiotherapy: Not specified Surgery: No prior surgical removal of the entire colon, one lung, or the entire prostate Other: No concurrent treatment for cancer other than nonmelanomatous skin cancer