Healthy lifestyle factors – such as abstinence from smoking and drinking, low body mass index, and exercise – are correlated with decreased cancer incidence even in individuals with a high genetic risk.
This is according to a study – “Genetic risk for overall cancer and the benefit of adherence to a healthy lifestyle” – that appeared in Cancer Research.
As it is, genetic research continues to uncover loci, or areas in DNA, with specific changes that influence cancer risk. Through this, researchers can define polygenic risk scores (PRS) — personalized estimates of an individual’s cancer risk — based on a patient’s unique combination of these changes.
However, most PRS are generated for a specific cancer type, rather than for overall cancer risk.
“A PRS indicating risk of a certain cancer is important but not enough,” Guangfu Jin said. “We tried to create an indicator—the cancer polygenic risk score (CPRS)—to measure the genetic risk of cancer as a whole.”
For this study, Jin and his colleagues calculated individual PRS for 16 cancers in men and 18 cancers in women, using available data from genome-wide association studies involving 202,842 men and 239,659 women from the UK Biobank.
The researchers found that:
- Patients with the highest quintile CPRS were nearly twice as likely (for men) and 1.6 times as likely (for women) to have a cancer diagnosis by their most recent follow-up, in 2015 or 2016.
- 97% of patients in the study had a high genetic risk (top quintile) of at least one cancer type, suggesting that “almost everyone is susceptible to at least one type of cancer,” Jin said. “It further indicates the importance of adherence to a healthy lifestyle for everyone.”
- Patients with an unfavorable lifestyle and the highest quintile genetic risk were 2.99 times (in men) and 2.38 times (in women) more likely to develop cancer than those with a favorable lifestyle and the lowest quintile of genetic risk.
Among patients with high genetic risk, the five-year cancer incidence was 7.23% in men and 5.77% in women with an unfavorable lifestyle, compared with 5.51% in men and 3.69% in women with a favorable lifestyle. The decreased percentages are comparable to the cancer risk in individuals with intermediate genetic risk, Jin said. Similar trends were observed in all genetic risk categories, suggesting that patients could benefit from a healthy lifestyle regardless of genetic risk.
The findings “indicate that everyone should have a healthy lifestyle to decrease overall cancer risk,” Jin said. “This is particularly important for individuals with a high genetic risk of cancer. We hope our CPRS could be useful to improve a person’s awareness of their inherited susceptibility of cancer as a whole and facilitate them to participate in healthy activities.”