[18F]-FDG PET-CT prediction of response to induction chemotherapy in head and neck squamous cell carcinoma: Preliminary findings

ObjectivesThe present study assessed the predictive value of [18F]-FDG PET-CT (positron emission tomography with 18-fluoro-eoxyglucose radiotracer, coupled to computerized tomography) for response to induction chemotherapy in head and neck squamous cell carcinoma (HNSCC).Material and methods[18F]-FDG PET-CT was systematically performed before treatment initiation and after the first cycle of chemotherapy. Results were compared with those of endoscopy and pathologic analysis of biopsy and surgical specimens.ResultsThis preliminary study included 21 previously untreated HNSCC patients. A decrease of more than 30% in SUVmax (maximum standard uptake value) during induction was predictive of tumor response to chemotherapy (P = 0.04). PET-CT measurement of hypermetabolic volume based on a predetermined SUV threshold (SUV = 2.5), on the other hand, proved non-predictive.ConclusionThese preliminary findings are promising. A larger sample, however, would be required in order to determine a more precise SUVmax reduction cut-off threshold during induction. Other methods for determining metabolic volume thresholds will be investigated. If functional imaging proves contributive, it could enable early screening of non-responders, avoiding unnecessary intoxication.