Imaging, Diagnosis, Prognosis Metabolic Tumor Volume of [F]-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Predicts Short-Term Outcome to Radiotherapy With or Without Chemotherapy in Pharyngeal Cancer

Purpose: This study aimed to investigate whether metabolic tumor volume (MTV) measured from [F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) predicts short-term outcome to radiotherapy with or without chemotherapy and disease-free survival (DFS) in patients with pharyngeal cancers. Experimental Design: The MTVs of primary sites with or without neck nodes were measured in 82 patients. Short-term outcome was assessed using the treatment response evaluation by the Response Evaluation Criteria in Solid Tumors and recurrence events during follow-up (complete response/no recurrence or residual disease/recurrence). Results: A total of 64 patients had complete response/no recurrence as of the last follow-up. A cutoff of 40 mL for the MTV was the best discriminative value for predicting treatment response. By univariate analyses, patients with MTV >40 mL showed a significantly lower number of complete response/no recurrence than did patients with MTV ≤40 mL [68.2% versus 87.8%; hazard ratio (HR), 3.34; 95% confidence interval (95% CI), 1.09-10.08; P = 0.03], as is the same in tumor-node-metastasis stage (87.5% for I-II versus 90% for III versus 63.8% for IV; P = 0.02). However, MTV was only a significant predictor of short-term outcome by multivariate analyses (HR, 4.09; 95% CI, 1.02-16.43; P = 0.04). MTV >40 mL indicated a significantly worse DFS than MTV ≤40 mL (HR, 3.42; 95% CI, 1.04-11.26;P = 0.04). The standardized uptake value for the primary tumor did not show any correlation with treatment outcome or DFS. Conclusion: MTV has a potential value in predicting short-term outcome and DFS in patients with pharyngeal cancers. (Clin Cancer Res 2009;15(18):5861–8) The tumor-node-metasis (TNM) stage (1) defines the T stage as the extent of primary tumor in terms of size in the greatest dimension and invasion to adjacent structure; it defines the N stage in terms of the size and multiplicity of involved lymph nodes. As stage is considered the most important prognostic factor, it is reasonable to assume that an advanced stage reflects tumor burden in the whole body of a patient more accurately than does an early tumor stage. Tumor burdens or tumor volumes, however, do not exactly correlate with tumor stage (2), because the size of the tumor in its greatest dimensions is not representative of the three-dimensional tumor volume. Although the two-dimensional parameter of a tumor is an important factor in surgical treatment, tumor burden, usually three-dimensional volumetric data, has become another important factor to be considered in radiotherapy or chemotherapy. Therefore, more reliable prognostic factors are needed for malignancies, for which the treatment of choice is nonsurgical. Standardized uptake value (SUV), a semiquantitative parameter in [F]-fluorodeoxyglucose positron emission tomography (FDG-PET) or fused [F]-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), is known to be a significant factor for prognosis and treatment guidance in many malignancies (3–8). Metabolic tumor volume (MTV), defined as the volume of tumor tissues with increased FDG uptake, is a novel index in FDG-PET and is the least studied factor so far. FDG target volume in previous studies was calculated mostly by visual delineation of tumor edge or Authors' Affiliations: Departments of Otorhinolaryngology-Head and Neck Surgery, Nuclear Medicine, Internal Medicine, Division of HematologyOncology, Radiation Oncology, Radiology, and Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea Received 12/20/08; revised 5/11/09; accepted 5/27/09; published OnlineFirst 9/8/09. Grant support: This work was supported by the Samsung Biomedical Research Institute (#SBRI C-A8-214-2). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Requests for reprints:Chung-HwanBaek,DepartmentofOtorhinolaryngologyHead and Neck Surgery, SamsungMedical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, 135-710, Seoul, Korea. Phone: 82-2-3410-3576; Fax: 82-2-3410-6987; E-mail: [email protected]. F 2009 American Association for Cancer Research. doi:10.1158/1078-0432.CCR-08-3290 5861 Clin Cancer Res 2009;15(18) September 15, 2009 www.aacrjournals.org Published Online First on September 8, 2009 as 10.1158/1078-0432.CCR-08-3290 Research. on May 1, 2017. © 2009 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Published OnlineFirst September 8, 2009; DOI: 10.1158/1078-0432.CCR-08-3290