Prediction of patient outcome with 2-deoxy-2-[18F]fluoro-D-glucose-positron emission tomography early during radiotherapy for locally advanced cervical cancer.

INTRODUCTION: It is difficult to assess the individual response of locally advanced cervical cancer to chemoradiation therapy during the course of treatment. We have investigated the predictive value of positron emission tomography (PET) with 2-deoxy-2-[18F]fluoro-D-glucose (FDG) early during treatment in relation to progression-free survival.

METHODS: This prospective single-center clinical trial included women with locally advanced cervical cancer from 2004 to 2008. 2-Deoxy-2-[18F]fluoro-D-glucose-PET/computed tomography was performed at baseline, during the third week of treatment and, finally, 3 months after the completion of treatment. The images were evaluated visually, semiquantitatively with the maximum standardized uptake value, and by calculating the metabolic rate of FDG. Thirty-two patients were eligible for full evaluation.

RESULTS: The median follow-up time was 28 months (range, 5-53 months). Visual metabolic complete response on FDG-PET, after a mean irradiation dose of 23 Gy (range, 16-27 Gy), was found in 7 patients, none of which relapsed. Eleven of the 25 patients with remaining malignant hypermetabolism on the second FDG-PET relapsed. Neither maximum standardized uptake value nor metabolic rate of FDG could further discriminate between patients with low risk and patients with high risk of relapse. The follow-up FDG-PET performed 3 months after the completion of treatment identified a group of patients with poor prognosis.

CONCLUSIONS: In conclusion, FDG-PET early during chemoradiation therapy identified a small number of patients with an excellent prognosis. However, FDG-PET at this early point in time during treatment failed to predict the outcome for most patients. Future clinical trials to determine the optimal timing of predictive FDG-PET are thus warranted.