Prognostic significance of mediastinal 18F-FDG uptake in PET/CT in advanced ovarian cancer.

Purpose: To evaluate the prognostic significance of increased mediastinal (18)F-FDG uptake in PET/CT for the staging of advanced ovarian cancer.

Methods: We retrospectively evaluated patients managed for FIGO stage III/IV ovarian cancer between 1 January 2006 and 1 June 2009. Patients were included if they had undergone (18)F-FDG PET/CT and surgery for initial staging. Exclusion criteria were age younger than 18 years, inability to undergo general anaesthesia, recurrent ovarian cancer, and borderline or nonepithelial malignancy. Whole-body PET/CT was performed after intravenous (18)F-FDG injection. The location of abnormal hot spots and (18)F-FDG maximal standard uptake values (SUV(max)) were recorded. We compared the complete cytoreduction and survival rates in groups defined based on mediastinal (18)F-FDG uptake and SUV(max) values. Kaplan-Meier curves of overall survival and disease-free survival were compared using the log-rank test. Hazard ratios with their 95% confidence intervals were computed. Adjusted hazard ratios were obtained using a multivariate Cox model.

Results: We included 53 patients, of whom 17 (32%) had increased mediastinal (18)F-FDG uptake. Complete cytoreduction was achieved in 14 (87.5%) of the 16 patients managed with primary surgery and in 21 (75%) of the 28 patients managed with interval surgery. Complete cytoreduction was achieved significantly more often among patients without increased mediastinal (18)F-FDG uptake (80.6% vs. 35.3%; p = 0.001). Disease-free survival was comparable between the two groups. By univariate analysis, overall mortality was significantly higher among patients with increased mediastinal (18)F-FDG uptake (hazard ratio 5.70, 95% confidence interval 1.74-18.6). The only factor significantly associated with overall survival by multivariate analysis was complete cytoreduction (adjusted hazard ratio 0.24, 95% confidence interval 0.07-0.89).

Conclusion: Increased mediastinal (18)F-FDG uptake was common in patients with advanced ovarian cancer. However, complete cytoreduction, which was significantly more frequent among patients without mediastinal (18)F-FDG uptake, was the only factor independently associated with survival.