- Compare the effectiveness of a computer-tailored, correspondence course vs standardized materials in promoting changes in diet and physical activity (PA) behaviors in patients with early stage prostate or breast (closed to accrual as of 8/1/03) cancer who currently do not practice goal behavior in at least 2 of the following 3 areas: performance of moderate PA for at least 150 minutes per week; consumption of at least 5 servings of vegetables or fruit daily; or consumption of a diet with less than 30% fat (with less than 10% of kilocalories from either saturates or polyunsaturates).