Table 4.

Primary and secondary prevention strategies of CRC.

Primary

(i) Diet. A diet high in vegetables, fruits, dairy products, olive oil, fish, and whole grains and low in red and processed meats has been shown to lower CRC risk [21–23].

(ii) Physical Activity. Physically active individuals have 24% lower risk of CRC development than those who have a sedentary lifestyle. Physical activity promotes the production of interleukin-6 (IL-6) and decreases the expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) in plasma and colon, leading to enhanced immunity [24, 25].

(iii) NSAIDs. They reduce the risk of CRC by blocking cyclooxygenase (COX) enzymes, so inhibit prostaglandin production, which are known to promote tumor angiogenesis and cell proliferation [26].

Secondary

(i) Fecal Tests. Fecal occult blood test (FOBT) and fecal immunochemical test (FIT) detect hidden blood in the stool, while fecal DNA test detects DNA in the stool [27–29].

(ii) Flexible Sigmoidoscopy. It is performed using an endoscope that allows the examination of the surface up to 60 cm from the anal verge (rectum, sigmoid colon, and part of the descending colon). It is done after colon lavage using enema or administering laxatives without the need of sedation [30].

(iii) Colonoscopy. It is performed using an endoscope, which allows an examination of the entire colon surface. It must be done under intravenous sedation and requires being on a low-residue diet, colon lavage using laxatives, and drinking plenty of water the day before the test [31].