EVALUATION OF CHEMOTHERAPY RESPONSE IN PATIENTS WITH ADVANCED HEAD AND NECK-CANCER USING [F-18] FLUORODEOXYGLUCOSE POSITRON-EMISSION-TOMOGRAPHY

Background. [F-18]Fluorodeoxyglucose (FDG)-positron emission tomograph y (PET) can measure the metabolic activity of tissues; FDG-PET may be able to predict response to chemotherapy by identifying changes in tum or metabolism. Measurement of response to treatment may help improve s urvival in the management of advanced head and neck cancer. We evaluat ed this particular use of FDG-PET in patients participating in a neoad juvant organ-preservation protocol using taxol and carboplatin and com pared pathologic response after chemotherapy with changes in tumor met abolism measured by FDG-PET. Methods. Serial FDG-PET studies (n = 56) were performed in patients (n = 28) with stage III/IV head and neck ca ncer participating in a neoadjuvant organ-preservation protocol. The F DG-PET studies were performed before and after chemotherapy. All patie nts had tissue biopsies before and after chemotherapy. Patients were c lassified as pathologic complete response (PCR) or residual disease (R D) based on tissue biopsies. Visual analysis of PET scans was performe d to identify patients with complete response by PET, and these findin gs were compared with pathology results. Metabolic changes were also e valuated using standardized uptake ratios (SUR) of FDG. Results. The s ensitivity and specificity of PET for residual cancer after therapy wa s 90% (19/21) and 83% (5/6), respectively. Two patients had initially negative biopsies and positive PET studies for persistent disease. Pat hology review and rebiospy led to confirmation of the PET results in t hese cases, giving a sensitivity of 90% for initial tissue biopsy. Con clusions. In this preliminary analysis, FDG-PET was accurate in classi fying response to chemotherapy in most patients. Fluorodeoxyglucose-PE T may identify residual viable tumor when it is otherwise undetectable . (C) 1997 John Wiley & Sons, Inc.