To the Editor
Cao et al¹ provided an emphasis regarding cancer prevention using aspirin in 2 large prospective cohort studies: the Nurses’ Health Study and Health Professionals Study. Overall cancer risk reduction was minimal, with a relative risk of 0.97 (95% CI, 0.94-0.99). The major benefit was for gastrointestinal cancers, mainly colorectal cancers. In 2016, colorectal cancer is estimated to ... [Show full abstract] make up 8% of all new cancer cases in United States.² The US Preventive Services Task Force recommends low-dose aspirin therapy for primary prevention of colorectal cancer for patients from age 50 to 59 years if they have a life expectancy of at least 10 years and are willing to take it for at least 10 years.³ In their study, the effect of aspirin therapy was cumulative and needed at least 6 years to show benefit.