Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for children and young adults: experience from two high volume centers.

Objectives: peritoneal surface malignancy in children is rare with a dismal prognosis. This bicentric study evaluated CRS with HIPEC in patients aged 2-25 years. Methods: Clinicopathological and treatment-related factors were retrospectively analyzed from 21 patients undergoing CRS and HIPEC between 2009 and 2022. Endpoints were feasibility, chemotherapeutic compound, complications, and overall survival (OS). Results: The mean age was 20.4 years. The mean peritoneal cancer index (PCI) was 12.8. Mean follow-up period was 6.8 years. Median overall survival time was 2.4. 5-year survival rate was 42.9 %. 76.2 % had primary and 23.8 % recurrent disease. The most common primary tumor locations were colon (33.3 %) and appendix (14.3 %). Adenocarcinoma was the most common histological subtype (71.4 %). Univariable Cox regression analysis showed significant impaired OS after previous chemotherapy (p=0.46) and incomplete cytoreduction CCR-2 (p=0.43). No perioperative mortalities occurred. The incidence of major complications was 24 %. Conclusions: Multimodal treatment can be considered in pediatric patients with peritoneal carcinomatosis. It presents a safe and feasible therapy with manageable complications and no perioperative mortality when performed by an experienced multidisciplinary team. Indication for CRS and HIPEC in children should be an individual decision by an interdisciplinary tumor board in the absence of better alternatives.