Pseudomyxoma peritonei: role of 18F-FDG PET in preoperative evaluation of pathological grade and potential for complete cytoreduction.

ABSTRACT

INTRODUCTION: For pseudomyxoma peritonei (PMP), survival depends on pathological grade and completeness of cytoreductive surgery. The aim of the study was to assess the ability of preoperative 18F-FDG PET to determine these 2 prognosis indicators. MATERIAL AND METHODS: In this prospective single centre study, all patients presenting with PMP were included. They underwent a preoperative 18F-FDG PET with a double radiological evaluation and an explorative laparotomy with the objective of optimal cytoreduction followed by a hyperthermic intra-operative intraperitoneal chemotherapy (HIPEC). Patients with non resectable disease underwent debulking surgery without HIPEC. The Completeness of Cytoreduction was assessed by CC score. RESULTS: Thirty-four patients were included. PET scanning was positive for 19 patients with grade II (hybrid form) or III (Peritoneal Mucinous Carcinomatosis) and for 2 patients with grade I (disseminated peritoneal adenomucinosis), and negative for 3 patients with grade II - III and for 10 patients with grade I. PET scanning was positive for 6 patients with CC score 2 - 3 and for 16 patients with CC score 0, and negative for 2 patients with CC score 2 - 3 and for 10 patients with CC score 0. The 18F-FDG PET interpretation distinguished 2 patients groups (grade I and grade II - III) with a sensitivity of 90% and a specificity of 77%. Moreover, probability of complete cytoreduction when PET was negative was over 80%. CONCLUSION: Preoperative 18F-FDG PET may predict pathological grade and completeness of cytoreduction which are the two main prognostic factors in patients with PMP.