The relative risk was further reduced as the number of aspirin tablets (325 mg) taken per week increased (0.5–1.5 vs 2–5 vs 6–14 vs >14; Ptrend=0.001), indicating that the chemopreventive effect was dependent upon both the dose and duration of aspirin intake (7), suggesting the importance of cumulative dosage as a determinant of aspirin efficacy in these settings.