Advancing treatment outcomes for peritoneal surface malignancies in low- and middle-income countries: Insights from the first multicenter study in north Africa.

e16476 Background: Peritoneal surface malignancies (PSM) are highly aggressive cancers with limited treatment access in low- and middle-income countries (LMICs). Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) has redefined survival outcomes globally, yet its feasibility and impact in LMICs remain underexplored. This first multicenter study in North Africa aimed to evaluate the efficacy and implementation of CRS with or without HIPEC, providing a critical benchmark for global oncology care in resource-limited settings. Methods: This retrospective cohort study included patients with histologically confirmed PSM (arising from colorectal cancer, pseudomyxoma peritonei, ovarian cancer, gastric cancer, or mesothelioma) treated with complete CRS with or without HIPEC between January 2014 and December 2020 at three tertiary centers in Rabat (Morocco), Tunis (Tunisia), and Batna (Algeria). The study protocol, including treatment protocols and endpoints—overall survival (OS), disease-free survival (DFS), and severe postoperative morbidity (Clavien-Dindo grade ≥ IIIa)—was reviewed prior to implementation. Multivariate Cox regression was used to identify independent predictors of survival outcomes. Results: A total of 391 patients were included in the study, with colorectal cancer (43%), pseudomyxoma peritonei (36%), ovarian cancer (12%), gastric cancer (6%), and mesothelioma (2%) as the primary tumor types. Complete cytoreduction (CC-0/1) was achieved in 88% of cases, and HIPEC was performed in 39%. Severe morbidity occurred in 22% of cases, with spleno-pancreatectomy, incomplete cytoreduction, and HIPEC identified as significant predictors. Mortality was reported in 6% of cases. The median overall survival (OS) was 68 months, with 1- and 5-year survival rates of 97% and 56%, respectively. The median disease-free survival (DFS) was 48 months. Patients undergoing CRS with HIPEC had significantly longer OS compared to those receiving CRS alone (70 months vs. 64 months, p = 0.016). No significant difference in DFS was observed between the two groups. Independent predictors of improved OS included primary tumor type, PCI, CC score, and HIPEC. For DFS, older age and lower tumor burden were protective factors, while incomplete cytoreduction was associated with worse outcomes. Conclusions: This pioneering study establishes that CRS and HIPEC are feasible and effective in LMICs, achieving survival outcomes comparable to high-income settings. With a median OS of 68 months and significant improvements in long-term survival, we highlight the potential for CRS and HIPEC to deliver meaningful disease control and long-term survival, even in resource-constrained settings. These results set a foundation for scaling advanced PSM treatments in LMICs, setting a new standard for global oncology care.