Is cancer interacting with diseases such as diabetes in overweight patients?
Heinz Freisling will study common cancers associated with adiposity, such as bowel and breast (in postmenopausal women), and cancers with a particularly strong association with adiposity and diabetes
Topic: Combination of cancers
Institution: International Agency for Research on Cancer (IARC)
"Recently, I had the pleasure to visit the office of WCRF International in London and I was impressed to see the enthusiasm and spirit of all the great persons working there and collectively contributing to cancer prevention. I find it very reassuring that not-for-profit organisations such as the WCRF exist and support independent research on the impact of modifiable lifestyle factors on preventable cancer burden"
– Heinz Freisling
Obesity and cancer risk, and overall and cancer specific mortality among cancer patients: the role of comorbidities
Overweight and obesity are established risk factors for several common cancers such as bowel cancer. Cancer and other chronic diseases, such as cardiovascular diseases (CVD) or diabetes, often share common risk factors such as adiposity, and tend to co-occur within the same individuals. Four in ten patients with cancer have at least one other chronic condition. This indicates that there might be sub-groups among overweight and obese individuals whose cancer risk is modified by factors other than adiposity. Given the link between adiposity and the development of these diseases, comorbidities such as CVD and diabetes may modify cancer processes and synergistically stimulate biological processes that promote cancer. Furthermore, comorbid conditions may also activate additional biological processes or may influence cancer processes through external factors such as treatment for these comorbid diseases. Yet, the contribution of comorbidity to cancer risk among overweight or obese individuals is unclear. Similarly, adiposity has also been linked to poorer survival in cancer patients, and patients diagnosed with cancer who have pre-existing comorbidities such as diabetes have lower survival rates compared with those without diabetes. However, the interplay between obesity and comorbidities on cancer survival is uncertain.
Aims and objectives
The overall aim of this project is to investigate whether the occurrence of a major comorbidity – CVD or diabetes – prior to cancer modifies associations between obesity and risk of cancer development and death from cancer. We will specifically investigate common cancers associated with adiposity, such as bowel cancer and breast cancer (in postmenopausal women), and cancers with a particularly strong association with adiposity and diabetes that include pancreatic cancer and endometrial cancer.
How it will be done
In our proposed study design, we will include study participants from large population-based observational studies, who are free of cancer and comorbidities at enrolment and follow them up during adult life and eventual development of comorbidities, cancer, and death. We will compare differences in risk of cancer development and death from cancer between normal weight and overweight and obese individuals in the presence or absence of CVD or diabetes. We will also take the duration of overweight or obesity during adult life and the duration of comorbidities into consideration. We will control for other known risk factors including socio-demographic factors, education, lifestyle factors such as smoking, alcohol consumption, and diet as well as for comorbidities and cancer treatment. Finally, we will complement our study with data from large genetic studies and approaches to consolidate whether the potential associations we observe between obesity, comorbidities and cancer have a causal effect.
This project could provide a better understanding of how obesity interacts with major comorbidities related to cancer development and prognosis. This would lead to the identification of sub-groups among overweight and obese individuals, whose cancer risk is modified by factors other than adiposity. Such improved knowledge would permit a more focused approach to preventive or management strategies, and also guide interventions.