Adding Maximum Standard Uptake Value of Primary Lesion and Lymph Nodes in (18)F-Fluorodeoxyglucose PET Helps Predict Distant Metastasis in Patients with Nasopharyngeal Carcinoma

OBJECTIVE: To find out the most valuable parameter of (18)F-Fluorodeoxyglucose positron emission tomography for predicting distant metastasis in nasopharyngeal carcinoma. METHODS: From June 2007 through December 2010, 43 non-metastatic NPC patients who underwent (18)F-Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) before radical Intensity-Modulated Radiation Therapy were enrolled and reviewed retrospectively. PET parameters including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glucose (TLG) of both primary tumor and cervical lymph nodes were calculated. Total SUVmax were recorded as the sum of SUVmax of primary tumor and cervical lymph nodes. Total SUVmean, Total MTV and Total TLG were calculated in the same way as Total SUVmax. RESULTS: The median follow-up was 32 months (range, 23–68 months). Distant metastasis was the main pattern of treatment failure. Univariate analysis showed higher SUVmax, SUVmean, MTV, and TLG of primary tumor, Total SUVmax, Total MTV, Total TLG, and stage T3-4 were factors predicting for significantly poorer distant metastasis-free survival (p = 0.042, p = 0.008, p = 0.023, p = 0.023, p = 0.024, p = 0.033, p = 0.016, p = 0.015). In multivariate analysis, Total SUVmax was the independent predictive factor for distant metastasis (p = 0.046). Spearman Rank correlation analysis showed mediate to strong correlationship between Total SUVmax and SUVmax-T, and between Total SUVmax and SUVmax-N(Spearman coefficient:0.568 and 0.834;p = 0.000 and p = 0.000). CONCLUSIONS: Preliminary results indicated that Total SUVmax was an independently predictive factor for distant metastasis in patients of nasopharyngeal carcinoma treated with Intensity-Modulated Radiation Therapy.