Key risk factors for the relative and absolute 5‐year risk of cancer to enhance cancer screening and prevention

BACKGROUND: This study identifies populations who may benefit most from expanded cancer screening. METHODS: Two American Cancer Society prospective cohort studies, Cancer Prevention Study‐II Nutrition Cohort and Cancer Prevention Study‐3, were used to identify the risk factors associated with a > 2% absolute risk of any cancer within 5 years. In total, 429,991 participants with no prior personal history of cancer were followed for cancer for up to 5 years. Multivariable Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals for association. By using these hazard ratios, individualized coherent absolute risk estimation was used to calculate absolute risks by age. RESULTS: Overall, 15,226 invasive cancers were diagnosed among participants within 5 years of enrollment. The multivariable‐adjusted relative risk of any cancer was strongest for current smokers compared with never‐smokers. In men, alcohol intake, family history of cancer, red meat consumption, and physical inactivity were also associated with risk (p < .05). In women, body mass index, type 2 diabetes, hysterectomy, parity, family history of cancer, hypertension, tubal ligation, and physical inactivity were associated (p < .05). The absolute 5‐year risk exceeded 2% among nearly all participants older than 50 years and among some participants younger than 50 years, including current or former smokers (<30 years since quitting) and long‐term nonsmokers with a body mass index >25 kg/m(2) or a first‐degree family history of cancer. The absolute 5‐year risk was as high as 29% in men and 25% in women. CONCLUSIONS: Older age and smoking were the two most important risk factors associated with the relative and absolute 5‐year risk of developing any cancer.