Title PhD project: Lifestyle patterns after colorectal cancer diagnosis: role in cancer recurrence, comorbidities and survival
Duration: February 2017 - February 2021
Survival of colorectal cancer (CRC) has substantially improved in recent decades because of advancements in diagnosis and treatment. However, with increased survivorship many CRC patients experience CRC recurrence or new chronic conditions after previously completed treatment. Evidence is emerging that modifiable lifestyle factors, such as physical activity and dietary habits, could impact CRC survival. The role of lifestyle on other CRC outcomes, however, is unclear. Therefore, further research is needed into the impact of lifestyle on CRC recurrence and the risk of common comorbidities.
It is important to evaluate the combined effect of post-diagnostic lifestyle factors, which can be done with lifestyle pattern analyses. These analyses take the clustering of lifestyle factors within individuals into account and avoid multiple testing of single lifestyle factors. Lifestyle patterns should be assessed at various points in time during the cancer trajectory as lifestyle may change over time. Currently studies that evaluate the impact of lifestyle patterns among CRC patients on cancer outcomes are lacking.
Purpose of the project
The primary purpose of the project is to assess whether lifestyle patterns after CRC diagnosis - including diet, physical activity, smoking, alcohol consumption, adiposity, and dietary supplement use - are associated with cancer recurrence, comorbidities, and survival.
Plan of investigation
The study will be performed within two ongoing prospective cohort studies among 1,800 Dutch CRC patients. One of these cohorts is the COLON study initiated by Wageningen University. The other cohort is the EnCoRe study initiated by Maastricht UMC+.
Lifestyle patterns will be generated using two main approaches: 1) a hypothesis driven method by constructing a score based on current lifestyle guidelines for CRC patients, and 2) a data-driven method by using Principal Components Analysis. The association between lifestyle patterns and cancer recurrence, comorbidities, and death among CRC patients will be assessed by multivariable Cox proportional hazard models. To analyse changes over time, techniques for longitudinal data and Cox models with time-dependent variables will be used.
The proposed study will show whether modifiable lifestyle factors, including diet and physical activity, can impact health of CRC survivors in addition to improving overall survival.
Relevance to the patient
Currently, CRC patients are advised to follow lifestyle recommendations for the general public to prevent the development of cancer. The ultimate goal of this proposal is to empower CRC patients by providing lifestyle recommendations specifically for CRC survivors to prevent cancer recurrence. This will provide guidance to CRC survivors on how to influence their risk of CRC recurrence and comorbidities after diagnosis themselves. This study will provide the scientific evidence that is needed before recommendations specific for tertiary prevention can be established.