PATIENT CHARACTERISTICS: Age: 30 to under 75 Performance status: Physician's assessment of good general health required Life expectancy: At least 5 years Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Cardiovascular: No NYHA class III/IV status No history of angina No history of MI No history of stroke or TIAs No peripheral vascular disease No bleeding diathesis including hemorrhagic stroke No prophylactic aspirin for cardiovascular disease Other: No documented peptic ulcer disease within past 15 years No aspirin sensitivity including: Aspirin-induced asthma Bronchial hyper-reactivity Urticaria Angioedema No requirement for sodium warfarin or other anticoagulant No frequent (greater than 36 times/year) NSAID use within the past 5 years No recurrent arthritis or other musculoskeletal problems No narcotic or alcohol dependency (unless there has been at least a 6-month period of abstinence) No prior or concurrent malignancy within 5 years (including metastases) except nonmelanomatous skin cancer No pregnant or nursing women Effective contraception required of fertile women