Colorectal cancer (CRC) is one of the most prevalent forms of cancer, with well over 1 million new cases diagnosed worldwide each year. Many patients present with advanced disease for which treatment options are limited, resulting in about 700,000 deaths annually. Our collaborative team has developed a personalised medicine screening platform to guide patient-specific treatment for patients with CRC. Organoids from each patient are subjected to next-generation sequencing (WES, RNAseq) to identify actionable genetic alterations. We combine this knowledge with high-throughput drug testing to identify specific drug sensitivities for each patient. In general, drug sensitivities have been consistent with known genetic susceptibilities for each sample, but we have also revealed both private and shared drug sensitivities that were unexpected. This opens new options for treatment of this otherwise incurable disease. We are initially focussing on CRC patients with the worst prognosis: those with unresectable intraperitoneal disease- the leading cause of CRC-related mortality, but this platform has broad applicability across the spectrum of gastro-intestinal tract cancers.