Risk Factors

Risk factors for colorectal cancer (CRC) are categorized as either modifiable or nonmodifiable.1 Nonmodifiable risk factors include age and personal or family history of CRC.2,3 Personal or family history of CRC is associated with a high risk of developing CRC.2,3 Modifiable risk factors include many health- and wellness-related factors and are generally associated with an increased risk of CRC.2-5 In general, over half of all CRC is attributable to modifiable lifestyle factors.5

ASYMPTOMATIC PATIENTS ARE GENERALLY CONSIDERED TO BE AT AVERAGE RISK FOR CRC IN THE ABSENCE OF

 A personal history of:

  • CRC, adenomatous polyps, or IBD (including Crohn’s disease and ulcerative colitis)2,4,9
  • Radiation to the abdomen/pelvic area to treat prior cancer4
  • Cystic fibrosis and a confirmed or suspected high-risk CRC genetic syndrome (such as familial adenomatous polyposis or Lynch syndrome)3,10

A family history of:

  • First-degree relative who has had CRC or advanced lesions1
  • Familial adenomatous polyposis2,3
  • Hereditary CRC syndrome4

EACH PATIENT’S RISK MUST BE ASSESSED INDIVIDUALLY

Consider these risk factors when screening patients for CRC. The presence of these risk factors alone does not elevate patients beyond the average-risk category.

Figure depicting risk factors that can contribute towards development of colorectal cancer. The risk factors shown are cigarette smoking, diabetes, excess body weight, increased age, lack of physical activity, moderate to high consumption of alcohol and/or long-term consumption of red and processed meat, low consumption of fiber, calcium, fruits, and vegetables.
  • Having one or more first-degree relatives with CRC is associated with an increased or high risk for the development of CRC5
    • This risk is further increased when first-degree relatives with CRC are under the age of 50 years5
  • Certain factors associated with Western lifestyles are known to increase the risk of developing CRC
    • While assessment of these factors provides an important opportunity for lifestyle modification advice, their presence is not considered sufficient to elevate individuals beyond the average-risk category, and there is no evidence to support their use in stratifying subgroups of the population within the average-risk category4,11
  • In the United States, ~55% of all CRCs are attributable to modifiable lifestyle factors5

Established Colorectal Cancer Risk Factors5

Factors that increase risk Relative riskb
Hereditary and medical history
Family history of CRC
1 or more first-degree relatives 2.2
1 or more first-degree relatives diagnosed before age 50 3.6
2 or more first-degree relatives 4.0
1 or more second-degree relatives 1.7
Inflammatory bowel disease 1.7
Type 2 diabetes
Male 1.4
Female 1.2c
Modifiable factors
Heavy alcohol (daily average >3 drinks) 1.3
Obesity (body mass index ≥30 kg/m2) 1.3
Colon Male 1.5
Female 1.1
Rectum Male 1.3
Female 1.0
Red meat consumption (100 g/day) 1.1
Processed meat consumption (50 g/day) 1.2
Smoking (current vs never)
Proximal colon 1.2
Distal colon 1.1
Rectum 1.3
Factors that decrease risk
Physical activity (colon) 0.7
Dairy consumption (400 g/day) 0.9

Table adapted from ACS, 20235

  • People with a first-degree relative (parent, sibling, or child) diagnosed with CRC have 2-4x the risk of developing CRC, making timely screening critical in this population.5 Both a history of a distant relative and a family history of adenomas also increase the risk of developing CRC but to a lesser degree.2
  • Obesity, inactivity, smoking, heavy alcohol use, and high consumption of red or processed meat may also be considered when estimating CRC risk for individual patients.2,3,5
  • Learn more about genetic contributions and monitoring guidelines.

Related Topics

Footnotes

  1. This retrospective cohort study was conducted in a population of patients 18 or older with newly diagnosed metastatic colorectal cancer (mCRC). Data was sourced from linked medical and pharmacy claims data between January 2005 and June 2008 from two US-based Medstat MarketScan claims databases. Data was analyzed for comorbid conditions and medication use in the year prior to diagnosis of mCRC. Limitations include the fact that comorbidities were identified based on healthcare service use data; thus, comorbid conditions that did not trigger healthcare service use prior to diagnosis were not captured. In addition, history of smoking and obesity rates were very low, likely due to underreporting of these two conditions in claims databases. Univariate analyses were conducted to compare the comorbid conditions between patients aged ≥65 and <65 years old. In total, 12,648 patients aged ≥18 years were identified. The study was evenly populated by gender and age above and below 65, and most patients had a primary diagnosis of colon cancer (70.1%).
  2. The risk of disease in people with a particular “exposure” compared to people without the exposure. For dietary factors, the highest versus lowest consumption is compared. A value greater than 1 indicates higher risk with exposure, whereas less than 1 is a protective effect.
  3. The association was not statistically significant.

List of definitions

CRC: colorectal cancer; CVD: cardiovascular disease; IBD: inflammatory bowel disease; mCRC: metastatic colorectal cancer.


References

  1. Lewandowska A, Rudzki G, Lewandowski T, et al. Risk Factors for the diagnosis of colorectal cancer. Cancer Control. 2022;29:10732748211056692.
  2. PDQ Screening and Prevention Editorial Board. PDQ colorectal cancer prevention. National Cancer Institute. Updated March 29, 2021. Accessed May 30, 2023. https://www.cancer.gov/types/colorectal/hp/colorectal-prevention-pdq
  3. Davidson KW, Barry MJ, Mangione CM, et al. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA. 2021;325(19):1965-1977.
  4. Wolf AMD, Fontham ETH, Church TR, et al. Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society. CA Cancer J Clin. 2018;68(4):250-281.
  5. ACS. Colorectal cancer facts and figures 2023-2025. Atlanta: American Cancer Society; 2023.
  6. Ljubic B, Pavlovski M, Alshehri J, et al. Comorbidity network analysis and genetics of colorectal cancer. Inform Med Unlocked. 2020;21:100492.
  7. Hahn EE, Gould MK, Munoz-Plaza CE, et al. Understanding comorbidity profiles and their effect on treatment and survival in patients with colorectal cancer. J Natl Compr Canc Netw. 2018;16(1):23-34.
  8. Fu AZ, Zhao Z, Gao S, et al. Comorbid conditions in patients with metastatic colorectal cancer. World J Oncol. 2011;2(5):225-231.
  9. Gupta S, Lieberman D, Anderson JS, et al. Recommendations for follow-up after colonoscopy and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterol. 2020;158(4):1131-1153.e5.
  10. Scott P, Anderson K, Singhania M, Cormier R. Cystic fibrosis, CFTR, and colorectal cancer. Int J Mol Sci. 2020;21(8):2891.
  11. Rex DK, Boland CR, Dominitz JA, et al. Colorectal cancer screening: recommendations for physicians and patients from the U.S. Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol. 2017;112(7):1016-1030.