Accuracy of peritoneal carcinomatosis extent diagnosis by initial FDG PET CT in epithelial ovarian cancer: A multicentre study of the FRANCOGYN research group.

INTRODUCTION: Peritoneal carcinomatosis extent in ovarian cancer is difficult to evaluate by imaging techniques even though it determines the surgical complexity and survival. The aim of this study was to estimate the accuracy of 2-[18F]-fluoro-2-deoxy-d-glucose (FDG)-PET CT (Positron-emission tomography coupled with Computerised Tomography) performed before any treatment, in the diagnosis of the extent of peritoneal carcinomatosis. We compared these results to per-operative observations/ histology samples obtained during surgery (laparotomy/ laparoscopy).

MATERIAL AND METHODS: All women managed for an epithelial ovarian cancer between 1st January 2000 and 30th June 2016 were included if they had a FDG PET CT, before initiation of any treatment (neoadjuvant chemotherapy or frontline cytoreductive surgery). The extent of disease on histology samples from cytoreductive surgery/observations during exploratory laparoscopy were compared with the PET CT results.

RESULTS: Over the study period, 980 women were managed for epithelial ovarian cancer, among them 90 (9.2 %) had a PET CT before any treatment. The diagnostic reliability of an ovarian lesion was 67.8 %, a colon lesion was 61.25 %, a small intestine lesion was 50.6 %, an epiploic lesion was 41.7 %, a pelvic ganglionic invasion was 62.9 % and a paraortic lymph node invasion was 61.5 %. PET CT was less effective than a standard CT examination.

CONCLUSION: PET CT is not the most effective imaging examination to estimate the extent of peritoneal carcinomatosis during the initial management of an epithelial ovarian cancer.