Métastases péritonéales de cancer colorectal Cas particuliers: découverte peropératoire, métastases péritonéales et autres sites métastatiques, récidive après chirurgie de cytoréduction

Peritoneal metastases (PM) greatly impair prognosis of colorectal cancer, even more than other metastatic sites. PM should be treated by complete cytoreductive surgery (CRS). Then, complete peritoneal exploration is mandatory during colorectal primary tumour resection. In case of incidental diagnosis of synchronous PM during primary tumour surgery, the strategy should be discussed according to local expertise in peritoneal surgery and peritoneal spread of the disease. Up-front concomitant CRS might be performed in case of PM limited to peritumoral area, only after a complete peritoneal exploration by laparotomy. On the contrary, patients with more extensive PM should be referred to an expert centre in peritoneal disease, to eventually perform CRS after preoperative systemic chemotherapy or to discuss loco regional treatment otherwise. Presence of extra-peritoneal metastases is a major prognostic factor. In the case of liver metastases associated to PM, combined surgery is feasible, when both liver and peritoneal diseases are limited achieving survival benefit, despite increased postoperative morbidity. In the case of pulmonary metastases, local treatment using percutaneous thermoablation can be considered, especially in patients with limited peritonal disease in absence of extraperitoneal metastases. After curative intent PM surgical treatment, most of the patients (over 80%) will relapse, with isolated peritoneal recurrence in one third of them. At that time, iterative CRS can be performed in selected patients (limited peritoneal extent, disease-free interval > 12 months, complete CRS). Survival after such a surgical procedure is lower compared to first intent CRS, but better than that of patients treated with systemic chemotherapy.