Aspirin Use Shows Greater Benefit for Colon Cancer Risk Reduction in Individuals with Unhealthy Lifestyles: JAMA

USA: A recent study published in JAMA Oncology concluded that people who are at higher risk for colorectal cancer due to an unhealthy lifestyle may benefit from aspirin in terms of reducing their risk factors.

Colorectal cancer is the cancer of the colon or rectum. Unhealthy lifestyle, obesity, low physical activity, smoking, heavy alcohol consumption, presence of ulcerative colitis, and Crohn's disease are the risk factors which are associated with colorectal cancer. Considering this, Daniel R. Sikavi, from the Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, et.al conducted a study to evaluate whether the usage of aspirin is linked to the risk of colorectal cancer considering different lifestyle risk factors.

For this purpose, the research team conducted a prospective cohort study involving women nurses from 1980 to 2018 and male health professionals from 1986 to 2018. Data analysis was conducted between October 1, 2021- May 22, 2023.

The study assessed several outcomes, including the 10-year cumulative incidence of colorectal cancer (CRC) adjusted for multiple variables, the absolute risk reduction (ARR) with regular aspirin use, and the number needed to treat to achieve this benefit, all based on lifestyle scores. Additionally, it evaluated the multivariable-adjusted hazard ratios for developing CRC according to different lifestyle scores. Based on body mass index, alcohol intake, physical activity, and smoking a healthy lifestyle score was calculated. Regular consumption of aspirin tablets was defined as taking 2 or more standard tablets each week.

The findings revealed that:

• The average baseline age of the 107,655 study participants—comprising 63,957 women from the Nurses' Health Study and 43,698 men from the Health Professionals Follow-Up Study—was 49.4 years.

• Over 3,038,215 person-years of follow-up, 2,544 new cases of colorectal cancer were recorded. The 10-year cumulative incidence of CRC was 1.98% for participants who used aspirin regularly, compared to 2.95% for those who did not, resulting in an absolute risk reduction (ARR) of 0.97%.

• The ARR from aspirin use was highest among individuals with the poorest lifestyle scores and decreased progressively with improving lifestyle scores.

• The 10-year absolute risk reduction for participants with lifestyle scores of 0 to 1 (indicating the least healthy lifestyles) was 1.28%. In comparison, the ARR for those with lifestyle scores of 4 to 5 (indicating the healthiest lifestyles) was 0.11%.

• The number needed to treat with aspirin over 10 years was 78 for participants with scores of 0 to 1, 164 for those with a score of 2, 154 for those with a score of 3, and 909 for those with scores of 4 to 5.

• Among the elements of the healthy lifestyle score, the most significant differences in absolute risk reduction (ARR) from aspirin use were found for body mass index and smoking.

“The researchers concluded that lifestyle risk factors are valuable for identifying individuals who have a more favorable risk-benefit profile for cancer prevention with aspirin use”, the researchers concluded.

Reference

Sikavi, D. R., Wang, K., Ma, W., Drew, D. A., Ogino, S., Giovannucci, E. L., Cao, Y., Song, M., Nguyen, L. H., & Chan, A. T. (2024). Aspirin Use and Incidence of Colorectal Cancer According to Lifestyle Risk. JAMA oncology, 10.1001/jamaoncol.2024.2503. Advance online publication. https://doi.org/10.1001/jamaoncol.2024.2503