Role of PET Scan in the Evaluation of Early Response to Maintenance Treatment in Advanced Non-small-cell Lung Cancer

Non small cell lung cancer is the first cause of cancer related death in France and is becoming an increasing health problem in developing countries. Recently for patient with no progression disease after first line chemotherapy, new therapies were validated in maintenance (bevacizumab) or switch maintenance treatment (erlotinib, pemetrexed) with improved survival. Until now, determination of efficiency of treatment is only based on morphological response (RECIST) and remains inappropriate to such cytostatic drugs for which there is no anatomical lesion modification. Nuclear Medicine and especially 18-FDG Positron Emission Tomography (PET) offers a biologically relevant tool for assessment of tumour response therapies. The assumption of the study is that FDG PET would allow to earlier detect a lack of response, thereafter, to modify an ineffective treatment. Indeed, nowadays the treatment is maintained up to evidence of progression disease. However, despite the increasing use of FDG PET for predicting therapeutic response, there are no validated criteria for judging response of maintenance therapy in non-small cell lung cancer. It seems necessary to determine standardized criteria response, earlier during the course of maintenance therapy in patient with non small cell lung cancer. The final aim is to optimize survival by an adapted metabolic imaging guided therapy.