Colorectal Cancer: Epidemiology, Risk Factors, and Prevention

Abstract

Colorectal cancer (CRC) is the third most common cancer and the second most common cause of cancer mortality worldwide. There are disparities in the epidemiology of CRC across different populations, most probably due to differences in exposure to lifestyle and environmental factors related to CRC. Prevention is the most effective method for controlling CRC. Primary prevention includes determining and avoiding modifiable risk factors (e.g., alcohol consumption, smoking, and dietary factors) as well as increasing protective factors (e.g., physical activity, aspirin). Further studies, especially randomized, controlled trials, are needed to clarify the association between CRC incidence and exposure to different risk factors or protective factors. Detection and removal of precancerous colorectal lesions is also an effective strategy for controlling CRC. Multiple factors, both at the individual and community levels (e.g., patient preferences, availability of screening modalities, costs, benefits, and adverse events), should be taken into account in designing and implementing CRC screening programs. Health policymakers should consider the best decision in identifying the starting age and selection of the most effective screening strategies for the target population. This review aims to present updated evidence on the epidemiology, risk factors, and prevention of CRC.

Keywords: colorectal cancer; epidemiology; prevention; risk factors; screening.

Figure 1

Estimated age-standardized incidence rate for colorectal cancer, 2020 (Data source: GLOBOCAN 2020; Map production: IARC, http://gco.iarc.fr/today, accessed on 10 October 2023).

Figure 2

Age-standardized incidence rates (ASRs) (per 100,000 person-years) in 2020 (A) and estimated annual percentage changes (EAPCs) in ASRs (B) for colorectal cancer in selected transitioned (Denmark, Australia, Canada, Sweden, USA) and transitioning (Brazil, Costa Rica, Colombia, Kuwait, India) countries (Source: GLOBOCAN 2020; Figure production, B: IARC, http://gco.iarc.fr/overtime, accessed on 23 March 2023) (* subnational data).

Figure 3

Estimated annual percentage changes (EAPCs) of the age-standardized incidence rates (ASRs) for early-onset colorectal cancer (EOCRC) (age 0–49 years) in selected developed (Denmark, Australia, Canada, Sweden, USA) and developing (Brazil, Costa Rica, Colombia, Kuwait, India) countries (Source: GLOBOCAN 2020; Figure production: IARC, http://gco.iarc.fr/overtime, accessed on 23 March 2023) (* subnational data).