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Colorectal Cancer: Disease Risk and Prevention
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Worldwide, colorectal cancer (CRC) is the third most common cancer.1 Global statistics estimate that close to one million deaths were due to CRC in 2022 and more than 1.9 million new cases of CRC were diagnosed the same year.1 In the United States, the American Cancer Society ranks colon and rectum cancers third for new cancer cases and second for cancer-related deaths when statistics for men and women are combined.2,3
Family history of CRC or family history of a hereditary CRC syndrome such as Lynch syndrome are considered high-risk factors for colon and rectum cancers. Additionally, advanced age and race are two other unmodifiable risk factors for CRC. While early-onset CRC in those younger than 50 years of age accounts for approximately 10% of current diagnoses and the incidence is increasing in this population,4 the majority of CRC cases are diagnosed in adults over the age of 50. For Black adults in the US, CRC is the third most common cancer, and statistics from 2021 indicate that new colon and rectum cancer cases in the US are highest among adults who identify as Black, American Indian, or Alaska Native.5,6
While some risk factors cannot be changed, others may be modified to help decrease the chances of developing colon and rectum cancers. What lifestyle-based considerations, behaviors, and personalized therapeutic approaches may help lower the risk of disease?
Lifestyle & Other Risk Factors
Several lifestyle-based and behavioral risk factors have been associated with an increased risk of developing CRC, including:7-9
- Smoking
- Decreased levels of physical activity
- Increased sedentary behaviors
- Increased alcohol intake
- Decreased consumption of fiber and plants
- Increased consumption of red and processed meats
Reporting also indicates other potential risk factors for the development of CRC, such as the following:7,10-16
- Excess weight and obesity
- Disruption of intestinal flora called gut dysbiosis, characterized by a loss of protective bacteria, an enrichment of pathogenic and cancer-promoting bacteria, and possible altered fungal composition
- Comorbidities such as type 2 diabetes, inflammatory bowel disease, and periodontal (gum) disease
Environmental toxicant exposures, including proximity to industrial complexes, may also increase the risk of CRC development.15,16 Results from a recent study showed a significantly increased odds of developing CRC among those who lived near industries, from 1 km to 3 km.15 Greater odds of CRC were reported for industries releasing air pollutants versus pollutants via water routes.15
Early-onset and late-onset colorectal cancer
As mentioned, the majority of CRC cases are diagnosed in adults who are over the age of 50, yet incidence of early-onset CRC is increasing in the US and other industrialized countries, and patients often present with advanced disease, which has led to an increase in CRC-related deaths in younger patients.4,17 In response to the increasing cases of early-onset CRC, in May 2021, the US Preventive Services Task Force lowered the recommended age for CRC screening for those adults at average risk from 50 to 45.18 However, due to the recency, the effectiveness of earlier screening on outcomes for early-onset CRC has not yet been evaluated.
Research studies continue to investigate the disease development of early-onset CRC to help identify risk factors and clarify characteristics that may distinguish the disease process and outcomes from colon and rectum cancers in older adults.13,19 A recent study identified several significant risk factors for early-onset CRC, including CRC history in a first-degree relative, a high concentration of fat in the blood, obesity, and high alcohol consumption.20 Studies have also found that patients with early-onset CRC are more likely to be diagnosed at an advanced stage, to have rectal tumors, to have less comorbidities, to be female, and to have Medicaid.17
Lifestyle Modifications for Prevention
In addition to preventative screenings, lifestyle-based approaches may help lower risk of colon and rectum cancers, including the following:21,22
- A nutrient-dense diet high in fruit, vegetables, and whole grains and low in animal fats
- Increasing physical activity
- Maintaining a healthy weight
- Limiting alcohol consumption
- Increasing soluble and insoluble fiber consumption
- Avoiding smoking
A recent large study with over three million participants overwhelmingly suggested that plant-based diets were significantly associated with both reduced risk of developing and odds of having tumors in the digestive system.23 Specific to colon and rectum cancers, the study indicated that a plant-based diet significantly reduced the risk of colorectal, rectal, and colon cancers by 24%, 16%, and 12%, respectively.23
Conclusion
Research continues to clarify the various risk factors involved in the development of both early-onset and late-onset CRC. Foundational functional medicine interventions for gut balance and health such as nutrition and movement are among those modifiable lifestyle factors that may help in cancer prevention and are also low-risk therapeutic approaches to optimize overall health and wellness.
Within the functional medicine framework, practitioners collaborate with patients to develop personalized therapeutic strategies that are most beneficial to their current conditions and concerns. Click below to find a functional medicine practitioner near you to learn more about personalized lifestyle-based interventions that help address cancer risk and support gut health.
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References
- World Cancer Research Fund International. Colorectal cancer statistics. Accessed October 7, 2024. https://www.wcrf.org/cancer-trends/colorectal-cancer-statistics/
- Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer statistics, 2022. CA Cancer J Clin. 2022;72(1):7-33. doi:3322/caac.21708
- The American Cancer Society medical and editorial content team. Key statistics for colorectal cancer. American Cancer Society. Updated January 29, 2024. Accessed October 7, 2024. https://www.cancer.org/cancer/colon-rectal-cancer/about/key-statistics.html
- Sinicrope FA. Increasing incidence of early-onset colorectal cancer. N Engl J Med. 2022;386(16):1547-1558. doi:1056/NEJMra2200869
- Giaquinto AN, Miller KD, Tossas KY, Winn RA, Jemal A, Siegel RL. Cancer statistics for African American/Black people 2022. CA Cancer J Clin. 2022;72(3):202-229. doi:3322/caac.21718
- US Cancer Statistics Working Group. US cancer statistics data visualizations tool. US Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer Institute. Published June 2024. Accessed October 7, 2024. https://gis.cdc.gov/Cancer/USCS/#/Demographics/
- Song M, Chan AT, Sun J. Influence of the gut microbiome, diet, and environment on risk of colorectal cancer. Gastroenterology. 2020;158(2):322-340. doi:1053/j.gastro.2019.06.048
- Hermelink R, Leitzmann MF, Markozannes G, et al. Sedentary behavior and cancer—an umbrella review and meta-analysis. Eur J Epidemiol. 2022;37(5):447-460. doi:1007/s10654-022-00873-6
- Papadimitriou N, Bouras E, van den Brandt PA, et al. A prospective diet-wide association study for risk of colorectal cancer in EPIC. Clin Gastroenterol Hepatol. 2022;20(4):864-873.e13. doi:1016/j.cgh.2021.04.028
- Artemev A, Naik S, Pougno A, Honnavar P, Shanbhag NM. The association of microbiome dysbiosis with colorectal cancer. Cureus. 2022;14(2):e22156. doi:7759/cureus.22156
- Coker OO, Nakatsu G, Dai RZ, et al. Enteric fungal microbiota dysbiosis and ecological alterations in colorectal cancer. Gut. 2019;68(4):654-662. doi:1136/gutjnl-2018-317178
- The American Cancer Society medical and editorial content team. Colorectal cancer risk factors. American Cancer Society. Revised January 29, 2024. Accessed October 7, 2024. https://www.cancer.org/cancer/colon-rectal-cancer/causes-risks-prevention/risk-factors.html
- Gu J, Li Y, Yu J, et al. A risk scoring system to predict the individual incidence of early-onset colorectal cancer. BMC Cancer. 2022;22(1):122. doi:1186/s12885-022-09238-4
- Xuan K, Jha AR, Zhao T, Uy JP, Sun C. Is periodontal disease associated with increased risk of colorectal cancer? A meta-analysis. Int J Dent Hyg. 2021;19(1):50-61. doi:1111/idh.12483
- García-Pérez J, Fernández de Larrea-Baz N, Lope V, et al. Residential proximity to industrial pollution sources and colorectal cancer risk: a multicase-control study (MCC-Spain). Environ Int. 2020;144:106055. doi:1016/j.envint.2020.106055
- Pritchett N, Spangler EC, Gray GM, et al. Exposure to outdoor particulate matter air pollution and risk of gastrointestinal cancers in adults: a systematic review and meta-analysis of epidemiologic evidence. Environ Health Perspect. 2022;130(3):36001. doi:1289/EHP9620
- Cheng E, Blackburn HN, Ng K, et al. Analysis of survival among adults with early-onset colorectal cancer in the National Cancer Database. JAMA Netw Open. 2021;4(6):e2112539. doi:1001/jamanetworkopen.2021.12539
- Colorectal cancer: screening. US Preventive Services Task Force. Published May 18, 2021. Accessed October 7, 2024. https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening
- REACCT Collaborative, Zaborowski AM, Abdile A, et al. Characteristics of early-onset vs late-onset colorectal cancer: a review [published correction appears in JAMA Surg. 2021;156(9):894]. JAMA Surg. 2021;156(9):865-874. doi:1001/jamasurg.2021.2380
- O’Sullivan DE, Sutherland RL, Town S, et al. Risk factors for early-onset colorectal cancer: a systematic review and meta-analysis. Clin Gastroenterol Hepatol. 2022;20(6):1229-1240.e5. doi:1016/j.cgh.2021.01.037
- National Center for Chronic Disease Prevention and Health Promotion; Division of Cancer Prevention and Control. Reducing risk for colorectal cancer. Centers for Disease Control and Prevention. Published June 20, 2024. Accessed October 7, 2024. https://www.cdc.gov/colorectal-cancer/prevention/
- Arayici ME, Mert-Ozupek N, Yalcin F, Basbinar Y, Ellidokuz H. Soluble and insoluble dietary fiber consumption and colorectal cancer risk: a systematic review and meta-analysis. Nutr Cancer. 2022;74(7):2412-2425. doi:1080/01635581.2021.2008990
- Zhao Y, Zhan J, Wang Y, Wang D. The relationship between plant-based diet and risk of digestive system cancers: a meta-analysis based on 3,059,009 subjects. Front Public Health. 2022;10:892153. doi:3389/fpubh.2022.892153