The follow-up of patients after colorectal cancer surgery mainly consists of blood CEA assessments. These blood assessments could be done at home and could be beneficial in terms of patients' well-being and societal cost-effectiveness. Capillary blood sampling can be an alternative to venipuncture in home based or decentralized surveillance as it can be performed by the patient themselves. Before home based capillary sampling can be implemented, feasibility, reliability, and satisfaction for serum CEA measurements has to be determined.
The goal of this study is to determine the feasibility of CEA assessments at home using (automated) capillary sampling in patients in the follow-up after treatment for colorectal cancer.~The main questions it aims to answer are:~To determine the success rate of capillary sampling at home by the patient~To assess reliability and satisfaction of (automated) capillary CEA measurements Participants will be asked to perform automated capillary sampling and lancet capillary sampling at home twice after regular check-up visits in the hospital, with an interval of 3-6 months in between. During this hospital visit, a CEA measurement in blood sampled by venipuncture will be performed to act as a reference for the CEA measurements in (automated) capillary blood to be sampled at home.~Reliability of CEA measurements will be assessed for automated capillary and lancet capillary sampling compared to venipuncture.~Satisfaction in terms of patient reported outcomes (pain, burden, ease of use, and preference) will be evaluated.