How to measure peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) is the spread of a tumour in the peritoneum, sometimes originating from a primary tumour (mesothelioma, peritoneal serous carcinoma) and other times arising from a metastasis from another organ (ovary, colon, appendix, stomach). While it was previously considered incurable, significant improvements have been made thanks to new techniques such as cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). Patients who can benefit from these treatments are identified by radiologists who use imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET-CT). It is important to have an awareness of the different forms of presentation, methods of quantifying tumour burden (peritoneal carcinomatosis index, PCI), and criteria for unresectability for an accurate assessment of the disease's status. All this information should be shared and discussed in multidisciplinary boards for optimal and consensus-driven decision-making.