Can we Use a Simple Blood Test to Reduce Unnecessary Adverse Effects From Radiotherapy by Timely Identification of Radiotherapy-resistant Rectal Cancers? MeD-Seq Rectal Study

Pathological Response Rate, Circulating Tumour DNA

Chemoradiation therapy (CRT) followed by surgery is currently the standard of care to treat patients with locally advanced rectal cancer (LARC). CRT reduces local recurrences, but is associated with significant damage to the surrounding healthy tissue that can severely impact quality of life. Additionally, a proportion of patients (hardly) benefit from CRT. We aim to develop a diagnostic innovation, which can enable a more selective and thereby more effective use of the available therapies for rectal cancer patients. The objective of this study is to investigate whether patients can be identified who will response to CRT prior to start of the CRT in rectal cancer and therefore avoid possible severe side effects in patients who will not reponse on CRT.