Bardia A et al did however determine as part of a cohort study that cancer incidence and cancer mortality was reduced even in patients that used aspirin infrequently compared to those that never used it. In that study, women with the lowest all-cause mortality took aspirin 2-5 times per week. There was no statistically significant impact on cancer incidence or mortality among women who used non-aspirin NSAIDs, compared to those who did not. (28)
The safest approach is that aspirin should not be used specifically for cancer prevention, but if aspirin is used for cardiovascular disease prevention, there may be a small added benefit of cancer prevention.