The objective of this retrospective study was to evaluate the prognostic significance of volume-based metabolic markers of PET/CT along with clinical characteristics in patients with in-operable cervical carcinoma.
Methods: Fifty-eight patients with cervical carcinoma (stage IIB-IVB) underwent FDG PET/CT for pretreatment evaluation and included in this study. Patients were staged according to International Federation of Gynecology and Obstetrics [FIGO] system. After chemoradiation therapy, patients were evaluated for persistent disease (PD) by clinical examinations, smear tests, pelvic MRI and PET/CT. Based upon follow-up results, clinical characteristics (patient age, tumor histology, FIGO stage) and PET/CT findings such as presence of PET-positive pelvic/para-aortic lymph nodes (LN), metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum standardized uptake values (SUVmax) of tumor and lymph nodes were analyzed for disease persistence. Survival analysis for disease-free survival and overall survival was performed with Kaplan-Meier method using PET findings and clinical characteristics.
Results: At the time of last follow-up (mean: 22 ± 12.6 months, range 6-48), 38 patients (65 %) had PD, 20 patients (35 %) had no evidence of disease (NED). Patient age, tumor histology, MTV, TLG and tumor SUVmax did not differ between groups. The frequency of PET-positive pelvic/para-aortic lymph nodes (84 vs. 60 %, p = 0.03), LN SUVmax (10.2 vs. 6.5, p = 0.02), and FIGO stage differed significantly between PD and NED groups. Cox proportional hazards model demonstrated advanced FIGO stage and the presence of PET-positive para-aortic LN were independent predictors for PD. Both disease-free survival and overall survival curves showed progressive worsening as the disease advanced, p = 0.015. PET LN status was the most important prognostic indicator for disease-free survival and overall survival. The worst outcome curves were detected for patients with PET-positive para-aortic lymph nodes among all patients, p = 0.03.
Conclusion: Advanced FIGO stage and the presence of FDG-avid para-aortic lymph nodes on pretreatment PET/CT are significant prognostic biomarkers for PD and decreased overall survival in patients with in-operable cervical carcinoma independent from MTV, TLG, tumor and lymph node SUVmax.