The ctDNA-RECIST Trial Part One

Patients will be offered palliative systemic treatment according to standard of care. Response evaluation will be performed with the imaging-based RECIST according to standard guidelines. Treatment pauses according to institutional guidelines. Blood samples will be analyzed retrospectively to evaluate ctDNA.

"Patients are offered palliative systemic treatment according to standard of care. Response evaluation will be performed using ctDNA-RECIST.~ctDNA is measured before start of treatment. If the baseline sample is ctDNA negative the patient is transferred to an observational cohort, and sampling procedures continues as in the standard arm. If the baseline sample is ctDNA positive the patient continues in the ctDNA-RECIST guided arm. Treatment response is evaluated according to ctDNA-RECIST, and further sampling follows a predefined decision schedule."