Prospective evaluation of qualitative and quantitative ¹⁸F-FDG PET-CT parameters for predicting survival in recurrent carcinoma of the cervix.
Objective: The aim of this study was to evaluate the prognostic significance of qualitative and quantitative F-fluorodeoxyglucose (F-FDG) PET-computed tomography (PET-CT) parameters in patients with recurrent cervical carcinoma.
Methods: Twenty-six patients (age: 44 ± 10.1 years) with histologically proven recurrent carcinoma of the cervix (squamous, 21; adenocarcinoma, five) were prospectively enrolled and they underwent F-FDG PET-CT before salvage therapy. The qualitative parameters included for analysis were vaginal involvement, regional nodal metastasis, and distant metastasis on PET-CT. The quantitative PET-CT parameters included were standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). Cutoff values were determined using receiver operating characteristic curve analysis. A Kaplan-Meier analysis was carried out to compare survival among groups. Impact of PET-CT parameters on progression-free survival (PFS) and overall survival (OS) was evaluated using Cox proportional hazard regression.
Results: On PET-CT, vaginal involvement was seen in 16 patients, regional nodal metastasis in 12 patients, and distant metastasis (node and lung) in 11 patients. The mean SUVmax was 6.8 ± 4, MTV was 8.2 ± 12.8 ml, and TLG was 49.6 ± 108.4 ml. On multivariate analysis, SUVmax of up to 4.9 [hazard ratio (HR): 0.026, confidence interval (CI): 0.002-0.268, P=0.002] and distant metastasis (HR: 18.88, CI: 2.14-166.24, P=0.008) were independent predictors of PFS. On multivariate analysis, SUVmax greater than 9 (HR: 19.25, CI: 2.15-172.17, P=0.008) and distant metastasis (HR: 33.88, CI: 2.17-526.61, P=0.012) were also independent predictors of OS. MTV, TLG, and regional node involvement evaluated using PET-CT were found to be significant on univariate analysis but not on multivariate analysis.
Conclusions: SUVmax and the presence of distant metastasis on F-FDG PET-CT are independent predictors of PFS and OS in patients with recurrent cervical carcinoma.