Fig. 1.

Schematic overview of the study. Tissue from metastatic and primary CRC tumours was obtained via resection or biopsy prior to starting a new line of systemic treatment. PDOs were cultured and screened for standard-of-care treatments while the patient received standard systemic treatment. PDO drug screens were optimized by comparing various methods using a limited set of 5–11 PDOs, either among one another or by correlation with patient response. For all patients, organoid and patient response were compared for treatment given after the organoid was established