Use of 18F-FDG PET/CT in the preoperative evaluation of patients diagnosed with peritoneal carcinomatosis of ovarian origin, candidates to cytoreduction and hipec. A pending issue

• CT showed the better results confirming ovarian peritoneal disease than 18F-FDG PET/CT.
• CT and 18F-FDG PET/CT present a low detection capability for LSS-3 injury.
• Main utility of 18F-FDG PET/CT is the evaluation of extraperitoneal extension.

PurposeTo evaluate the clinical usefulness of the results obtained with 18F-FDG PET/CT in relation to CT in the preoperative staging of patients with peritoneal carcinomatosis secondary to primary or recurrent ovarian cancer candidates to cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC).Material and methodsA retrospective study comparing the results obtained with CT and 18F-FDG PET/CT in the preoperative evaluation of a series of 59 patients was performed. In all patients the peritoneal carcinomatosis index (PCI) was determined by preoperative radiological CT and 18F-FDG PET/CT and compared with surgical PCI, which was considered as reference.ResultsOf the 59 patients studied, in 55 peritoneal carcinomatosis presences were confirmed (4 patients had complete responses to neoadjuvant chemotherapy). The mean surgical, CT and 18F-FDG PET/CT PCI was 9.46 ± 7.70, 3.69 ± 3.96 and 2.25 ± 1.02, respectively. In the global disease detection, CT showed a higher positive likelihood ratio (LR+) than 18F-FDG PET/CT (15.3, 95% CI 8.35–28.04 vs. 3.47, 95% CI 3.36–5.11) and a lower negative likelihood ratio (LR-) than 18F-FDG PET/CT (0.67, 95% CI 0.61–0.73 vs. 0.82, 95% CI 0.76–0.88). In every region of the abdomen the CT showed a greater LR+ than 18F-FDG PET/CT and a lower LR- than 18F-FDG PET/CT.ConclusionsCT showed the best diagnostic results compared to 18F-FDG PET/CT to confirme the presence of peritoneal disease. The lower performance of the 18F-FDG PET/CT suggests that the main utility of 18F-FDG PET/CT is to evaluate a possible metastatic extraperitoneal spread of the disease.