To further optimize clinical care of patients with cancer there is a high need for reliable biomarkers to monitor the tumor during treatment. In this thesis the use of circulating tumor DNA to analyze the tumor at different timepoints was studied in patients with colorectal and esophageal cancer. Circulating tumor DNA is present in the blood of cancer patients and reflects the presence of tumor somewhere in the body. This research demonstrates that the levels of circulating tumor DNA in patients with non-metastatic disease are low and highly sensitive methods are required to measure this circulating tumor DNA. Furthermore, the results show that the presence of circulating tumor DNA during treatment can predict bad prognosis. Therefore, after further evaluation of its clinical utility these measurements may eventually help to make personalized treatment decisions.
Lisa Hofste (1993) obtained her Master’s degree in Biomedical Sciences at the Utrecht University after which she started with her PhD research at the Department of Human Genetics of the Radboud university medical center. Currently, she is working as an assistant clinical laboratory geneticist (not in training) at the department of Genetics of the UMC Utrecht.