Conversion to Complete Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Malignant Peritoneal Mesothelioma After Bidirectional Chemotherapy.

BACKGROUND: This report aims to describe preliminary results concerning secondary resectability after bidirectional chemotherapy for initially unresectable malignant peritoneal mesothelioma (MPM).

METHODS: Between January 2013 and January 2016, 20 consecutive patients treated for diffuse MPM not suitable for upfront surgery received bidirectional chemotherapy associating intraperitoneal and systemic chemotherapy. Evaluation of the response to chemotherapy was assessed clinically and by laparoscopy.

RESULTS: The median peritoneal cancer index (PCI) score at staging laparoscopy was 27 (range 15-39). Altogether, 118 intraperitoneal chemotherapy cycles were administered without any specific adverse catheter-related event. Concerning tolerance, 85% of the patients experienced no pain or mild pain during chemotherapy administration. The clinical response rate was 60% after a median of three chemotherapy cycles. At laparoscopic reevaluation, the median PCI was 18 (range 0-35), and a secondary resectability was considered for 55% of the patients. Complete cytoreduction surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) was finally achieved for 10 patients (50%), with a median intraoperative PCI score of 14 (range 6-30). After a median follow-up period of 18 months, the 2-year overall survival rate was 83.3% for the patients treated by CRS followed by HIPEC and 44% for the patients treated by bidirectional chemotherapy.

CONCLUSION: Bidirectional chemotherapy is a promising, well-tolerated treatment capable of increasing the resection rate for selected patients with diffuse MPM initially considered as unresectable or borderline resectable. For patients with definitively unresectable disease, bidirectional chemotherapy achieves a higher clinical response rate.