RT Journal Article SR Electronic T1 Early Response to Chemotherapy in Hypopharyngeal Cancer: Assessment with 11C-Methionine PET, Correlation with Morphologic Response, and Clinical Outcome JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 526 OP 532 VO 44 IS 4 A1 Eric Chesnay A1 Emmanuel Babin A1 Jean Marc Constans A1 Denis Agostini A1 Arnaud Bequignon A1 Armelle Regeasse A1 Franck Sobrio A1 Sylvain Moreau YR 2003 UL http://jnm.snmjournals.org/content/44/4/526.abstract AB Neoadjuvant chemotherapy in hypopharyngeal cancer globally improves survival, but some patients do not respond to chemotherapy and adjuvant therapy is delayed. Prediction of response to chemotherapy may allow physicians to optimize planned treatment. The aim of this study was to compare treatment response assessed early with 11C-methionine PET and morphologic response assessed after treatment completion with MRI. Methods: Thirteen patients with previously untreated squamous cell carcinoma of the hypopharynx, T3 or T4, were included. All patients received 3 courses of chemotherapy comprising cisplatin and 5-fluorouracil. 11C-Methionine PET was performed before and after the first course of chemotherapy. PET estimation of response was expressed in relative variation of mean standardized uptake value (SUVmean), maximal standardized uptake value (SUVmax), volume of 11C-methionine tumor uptake, and total tumor uptake. Posttreatment response was assessed with MRI, which was performed before the first course and after treatment completion, and expressed in relative variation of tumor volume. Patients were considered responders if their tumor volume was reduced by more than 50%. Results: The relative decrease in all PET parameters correlated significantly with the relative decrease in MRI volume. The larger area under the receiver operating characteristic curve was obtained for SUVmean (0.883), but that area was close to the area of SUVmax (0.857). For methodologic considerations, SUVmax was more reproducible. The optimal threshold of response for SUVmax was −25%, leading to a mean of 83% (range, 36%–93%) sensitivity and 86% (range, 42%–100%) specificity. Using this threshold, survival at 2 y was improved for responders (83%), compared with nonresponders (57%), but the difference was not statistically significant. Conclusion: 11C-Methionine PET provides early useful information about changes in tumor metabolism induced by chemotherapy in hypopharynx cancer. 11C-Methionine PET measurements correlate with end-of-treatment response evaluated with MRI and may thus be helpful to physicians in treatment planning by avoiding unnecessary chemotherapy courses for nonresponding patients.