Risk-based allocation and optimal duration of adjuvant treatment in stage II colon cancer: Model-based evaluations to provide guidance in the decision making process

This thesis focuses on the evaluation of the optimal allocation and duration of adjuvant chemotherapy in stage II colon cancer patients. We first estimated the effect of adjuvant treatment on disease-free survival in stage II colon cancer patients using pooled data from randomized clinical trials (RCTs). Subsequently, the RCT estimate was compared to estimates based on real-world data. Furthermore, the longitudinal influence of chemotherapy on a patient's quality of life was investigated. Using the findings of these studies, we developed the “Personalized Adjuvant TreaTment in EaRly stage coloN cancer” (PATTERN) model that describes disease progression and treatment of early stage colon cancer, taking pathological-, clinical- and biomarker features of the patient population into account. Using the PATTERN model, first the optimal duration of adjuvant chemotherapy in terms of quality adjusted life years and costs was evaluated. Subsequently, the cost-effectiveness of different strategies to allocate adjuvant chemotherapy in stage II colon cancer patients was assessed.