Lymph node-to-primary tumor standardized uptake value ratio on PET predicts distant metastasis in nasopharyngeal carcinoma.

OBJECTIVES: To investigate the prognostic value of the relative maximum standardized uptake value (SUV) ratio between neck lymph node and primary tumor (NTR) measured by pretreatment 18F-FDG PET in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: We retrospectively reviewed patients with non-disseminated NPC who underwent PET scans before radical intensity-modulated radiotherapy (IMRT). Receiver operating characteristic analysis was performed to identify the optimal cut-off value for NTR. The prognostic value of NTR for distant metastasis-free survival (DMFS) was evaluated using Kaplan-Meier method for survival analyses and Cox regression for multivariable analysis. RESULTS: Among the 437 eligible patients, the median follow-up time was 62.9 (range, 2.1-113.0) months. Patients with high NTR (NTR > 0.9181) experienced significantly worse DMFS (5-year 80.5% vs. 91.6%, P < 0.001). In the subgroup analysis, we found that patients with high NTR had significantly lower DMFS in T1-2 category (5-year 86.1% vs. 98.1%, P = 0.002), T3-4 category (5-year 71.5% vs. 86.2%, P = 0.010), N2-3 category (5-year 75.3% vs. 86.2%, P = 0.048), and stage IVA-B (5-year 69.8% vs. 85.4%, P = 0.012). Multivariable analysis showed that NTR was an independent prognostic factor for DMFS (HR 2.20, 95% CI 1.20-4.03, P = 0.011). CONCLUSION: Pretreatment NTR is an easily accessible but potential prognosticator for DMFS in NPC patients treated by IMRT, which may help in providing more personalized treatment or designing future clinical trials.

Prognostic value of lymph node to primary tumor standardized uptake value ratio in unresectable esophageal cancer.

BACKGROUND: Unresectable esophageal cancer harbors high mortality despite chemoradiotherapy. Better patient selection for more personalized management may result in better treatment outcomes. We presume the ratio of maximum standardized uptake value (SUV) of metastatic lymph nodes to primary tumor (NTR) in 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) may provide prognostic information and further stratification of these patients. METHODS: The patients with non-metastatic and unresectable esophageal squamous cell carcinoma (SCC) receiving FDG PET/CT staging and treated by chemoradiotherapy were retrospectively reviewed. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cut-off value for NTR. Kaplan-Meier method and Cox regression model were used for survival analyses and multivariable analyses, respectively. RESULTS: From 2010 to 2016, 96 eligible patients were analyzed. The median follow-up time was 10.2 months (range 1.6 to 83.6 months). Using ROC analysis, the best NTR cut-off value was 0.46 for prediction of distant metastasis. The median distant metastasis-free survival (DMFS) was significantly lower in the high-NTR group (9.5 vs. 22.2 months, p = 0.002) and median overall survival (OS) (9.5 vs. 11.6 months, p = 0.013) was also significantly worse. Multivariable analysis revealed that NTR was an independent prognostic factor for DMFS (hazard ratio [HR] 1.81, p = 0.023) and OS (HR 1.77, p = 0.014). CONCLUSIONS: High pretreatment NTR predicts worse treatment outcomes and could be an easy-to-use and helpful prognostic factor to provide more personalized treatment for patients with non-metastatic and unresectable esophageal SCC.