[Positron emission tomography with 18F-FDG and cancer response to chemotherapy].

INTRODUCTION: Few data are available about the predictive value of FDG-PET-CT in the evaluation of the response to chemotherapy of patients with advanced NSCLC and its impact on subsequent survival.

METHODS: A retrospective study of patients with advanced NSCLC who underwent a FDG-PET-CT before treatment and after three cycles of first-line chemotherapy. Morphological and metabolic responses were assessed respectively using RECIST/OMS and EORTC criteria. The relation between response and survival was analysed through Cox regression models.

RESULTS: Fifty-nine patients were included in the study (stage IIIA/IIIB/IV: 9/11/39). Median survival was 40 weeks (44 deaths observed). The evaluation of treatment response (morphological or metabolic, taken alone or combined) in terms of survival failed to identify any difference between responders and patients with stable disease. Only patients with progressive disease had a significantly shorter survival. The negative predictive value of the metabolic response for the morphological response is 0.90 and that of metabolic progression for morphological progression is 0.98.

CONCLUSION: Only progressive disease differs significantly from other types of response with a more sensitive and earlier detection by PET-CT.