Utility of 18F-FDG PET/CT in patients with advanced squamous cell carcinoma of the uterine cervix receiving concurrent chemoradiotherapy: a parallel study of a prospective randomized trial

The aim of this prospective study was to assess the usefulness of F-18-FDG PET/CT performed before and during treatment for predicting treatment failure in patients with advanced squamous cell carcinoma of the uterine cervix treated with concurrent chemoradiotherapy (CCRT). Patients with cervical squamous cell carcinoma, International Federation of Gynecology and Obstetrics stage III/IVA or positive pelvic or paraaortic lymph node (LN) metastasis without other distant metastasis on PET/CT entering a randomized trial of CCRT (AGOG 09-001) were eligible. PET/CT scans were performed at baseline, during week 3 of CCRT and 2 - 3 months after CCRT. PET/CT parameters were correlated with sites of failure and overall survival (OS). The resulting predictors developed from the study cohort were validated on two independent datasets using area under the curve values, sensitivities and specificities. With a median follow-up of 54 months for survivors, 20 (36 %) of the 55 eligible patients were proven to have treatment failure. Sites of failure were local in five, regional in 11, and distant in 11. Four predictors for local failure, three for regional failure, and four for distant failures were identified. After validation with two independent cohorts of 31 and 105 patients, we consider the following as clinically useful predictors: pretreatment metabolic tumour volume (MTV) and during-treatment cervical tumour MTV for local failure; during-treatment SUVnode (maximum standardized uptake value of LNs) for regional and distant failure, and during-treatment MTV for distant failure. During-treatment SUVnode (P = .001) and cervical tumour MTVratio (P = .004) were independent significant predictors of OS by stepwise Cox regression. PET/CT imaging before and during treatment is useful for predicting failure sites and OS, making tailored therapeutic modifications feasible with potential outcome improvement during primary therapy.