Abstract 586P
Background
Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS + HIPEC) represents the standard treatment of Malignant Peritoneal Mesothelioma (MPM) with 47% 5-year survival rate, but curative intent is frequently limited by the peritoneal extent at presentation. Palliative systemic chemotherapy (sysCT) alone achieves approximatively 10% 5-year survival rate. We previously reported our initial experience of bidirectional chemotherapy (bCT) for intially unresectable MPM as conversion option to CRS + HIPEC. The aim of this study is to analyze the impact in the management of MPM since the introduction of bCT in our center.
Methods
Patients with a histological diagnosis of MPM were enrolled and classified in upfront resectable (Res) and initially unesectable (Unres) MPM according to peritoneal extent based on CT scan and staging laparoscopy. The choice of bCT regimen between pemetrexed (500 mg/m2 combined with intravenous (IV) cisplatin 75 mg/m2 every 21 days) and oxaliplatin (100 mg/m2 combined with IV gemcitabine 1000 mg/m2 every 14 days) was performed according to previous treatments, potential side effects, and toxicity.
Results
52 patients with Res (n=24) and Unres (n=32) MPM were included (2012-2017). The mean peritoneal score index (PCI) was 17.8 ± 6 in Res and 26.8 ± 6.1 in Unres MPM (p <.001). A median of 5 cycle/patient of bCT was administered without any adverse catheter related event. Objective response was 86% (PCI 17.2 vs. 26.8, p= 0.001). Curative CRS + HIPEC was achieved in 50% of patients in Unres MPM. 90-day mortality rate was 4% and 0% (p NS) in Res and Unres MPM respectively. 3-ys DFS was 38.1% and 48.7% in bCT/CRS + HIPEC and Res groups (p NS). 3-ys OS was 90% and 78.3% in bCT/CRS+HIPEC and Res groups (p NS). Among definitively Unres MPM, median survival was 5.0 in patients treated by sysCT and and 31.9 months after bCT (p < .001), respectively.
Conclusions
bCT represents a promising model of locoregional intensification in Unres MPM with a secondary resection rate of 50% without higher toxicity providing similar survival rate compared to Res MPM in case of response as well as higher median survival in definitively Unres MPM (vs. sysCT).
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Gustave Roussy Digestive Unit Board.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.