- Screening for colorectal cancer is usually based on family history and age (in people with no family history).
- Current risk model for assessment of colorectal cancer uses a combination of genetic and lifestyle factors.
- The findings help to conclude that lifestyle factors like diet, physical exercise, body mass index and alcohol influence the risk of cancer more than genetics.
The risk of colorectal cancer can be reduced by improving lifestyle.
Researchers of the Colorectal Cancer research group of Bellvitge Biomedical Research Institute (IDIBELL), led by Dr. Víctor Moreno, and linked to the Catalan Institute of Oncology (ICO), the University of Barcelona (UB) and the Epidemiology and Public Health CIBER (CIBEResp), have issued the first predictive risk model of colon and rectal cancer based on Spanish data that combines genetic and lifestyle information.
‘People should be encouraged to adopt and achieve a healthier lifestyle as lifestyle factors weigh more than genetics in deciding the risk of colorectal cancer.’
Researchers used a combination of lifestyle and genetic information to subdivide the population into different groups according to their colon cancer risk.
"A risk model is a mathematical tool that allows us to predict who is most likely to suffer from a particular disease, in this case colon cancer," explains Dr. Moreno, head of ICO's Cancer Prevention and Control Program.
are tumors that arise from the lining of the large intestine. The risk of developing this cancer increases after the age of 50 years.
A diet low in fibers, high in fat, having a history of colorectal polyps, ulcerative colitis or Crohn's disease or family history increases the risk of colorectal cancers.
There was an estimated 134,490 number of cases of colon and rectal cancers and 49,190 related deaths in 2016 in U.S.
Assessing the Risk Using Lifestyle-Genetic Model
To develop this model, the researchers used data from the 10,106 participants included in the "MCC-Spain" Spanish multicentre study.
All participants were interviewed to analyze known risk factors like diet, physical exercise, body mass index, alcohol and family history of cancer.
To test the genetic predisposition of developing colon and rectal cancer, a blood test was performed in a subgroup of 1,336 cases of colorectal cancer and 2,744 controls.
The findings helped the research team to conclude that lifestyle influences cancer risk more than genetics.
Changing of a risky lifestyle choice is changed (for example, if a healthy weight is obtained), can compensate for having 4 genetic risk predisposition points (risk alleles).
"This is important considering that lifestyle, unlike genetic traits, is somewhat modifiable, while genetic susceptibility is inherited from our parents", says Dr. Gemma Ibáñez, a digestologist and first author of the study.
"In fact, the items we have identified as risk markers correlate with the recommendations set by the European Cancer Code to reduce the risk of cancer." Ibáñez added.
"Today, screening for colon cancer in patients with no family history is based solely on age. If we include information about lifestyle and genetics, we could classify the population into groups of greater or lesser risk, which would allow us to offer a more personalized follow-up", adds Dr. Moreno, who is also a professor at the UB Faculty of Medicine and Health Sciences.
"There are no studies that say what patients think about genetic tests, or whether they want to be informed of their chances of having certain diseases, and we think it is very relevant," says Dr. Ibanez.
Using the new model the researchers want to evaluate the utility of the risk score system for colon cancer by applying it prospectively in the population of Baix Llobregat.
The findings are published in Scientific Reports
- Cancer Stat Facts: Colon and Rectum Cancer - (https://seer.cancer.gov/statfacts/html/colorect.html)
- Colorectal Cancer - (https://medlineplus.gov/colorectalcancer.html
- Gemma Ibáñez et al. Risk Model for Colorectal Cancer in Spanish Population Using Environmental and Genetic Factors: Results from the MCC-Spain study. Scientific Reports; (2017) doi:10.1038/srep43263