Correlation Between Lymph Node Involvements, Survival And Primary Tumor Metabolic Parameters In Patients With Esophageal Squamous Cell Carcinoma

Part 1: Correlation between lymph node involvements and clinical and pathological parameters in esophageal squamous cell carcinoma patientsObjective: Lymph node involvement is an important factor in the planning of therapeutic strategies, particularly limited surgical resection and radiation field in patients with esophageal squamous cell cancer. Fluor-¹⁸-fluorodeoxyglucose positron emission tomography with computed tomography (¹⁸F-FDG PET-CT) has been used in the initial diagnosis, staging work-up, follow-up, and early detecting recurrence in many kinds of cancer. ¹⁸F-FDG uptake within the primary tumor correlates with aggressiveness on PET-CT studies. The more metabolically active the tumor, the more aggressive are the findings. The aim of this study was to determine whether ¹⁸F-FDG uptake of the primary tumor and the clinical and pathological parameters are predictors of lymph node metastasis in patients with esophageal squamous cell cancer.Methods: From March 2004 to March 2008, forty-night patients with esophageal squamous cell cancer were studied. All patients underwent a thoracotomy within 1 week of the ¹⁸F-FDG PET study. Multivariate and univariate analyses were performed with logistic analysis to assess the joint effects of the variables (age, sex, tumor length, T stage, differentiation grade, ¹⁸F-FDG uptake and so on) on lymph node involvement. Comparing group means use one-way ANOVA. Results: The mean SUV_max and MTV of lymph node metastasis group are 12.2±5.6 and 24.6±23.2 respectively, while they are 8.4±6.8 and 9.2±10.6 in the without lymph node metastasis group (P=0.047;P=0.015). Univariate and Multivariate analyses showed MTV was a significant factor for lymph node involvement (P=0.002, HR=8.171; P=0.030, HR=5.254).Conclusions: A significant correlation exists between the incidence of nodal involvement and the primary tumor MTV in patients with esophageal squamous cell carcinoma. And the value of primary lesion MTV is also the factor that should not be ignored in addition to considering the imaging of lymph nodes themselves. In patients with esophageal squamous cell carcinoma, MTV is a strong predictor of lymph node metastasis.Part 2: The correlation between FDG PET-CT metabolic tumor volume and prognosis in patients with esophageal squamous cell cancer after resectionObjective: Traditional prognostic factors can't predict treatment outcome reliably. Therefore, identification of novel prognostic factors that potentially predict outcome is thus of great interest. The identification of prognostic factors that accurately correlate with treatment outcome would help in the election which esophageal squamous cell cancer (ESCC) patients might benefit from more aggressive multimodality treatment, and consequently improve prognosis. In many kinds of cancer patients, ¹⁸F-FDG PET-CT has been used in the initial diagnosis, staging work-up, and early detection of recurrence. Furthermore, some studies have shown that tumor FDG uptake may have prognostic significance, in that patients with high FDG uptake generally have less favorable outcomes. Though many studies about the usefulness of FDG uptake have been made, the prognostic value of _maximum standard uptake value (SUV_max) and metabolic tumor volume (MTV) in resectable ESCC patients is still under investigation. This study evaluates the prognostic value of tumor burden measured by serial ¹⁸F-FDG PET-CT in patients with ESCC.Methods: Forty-night EC patients who had ¹⁸F-FDG PET-CT scan before surgery were studied retrospectively. Median duration of overall survival was 29 months (range, 8–57 months). The prognostic significances of MTV and other clinic-pathological variables (age, sex, histological grade, maximum SUV of primary tumor, tumor length measured on PET-CT, T stage, N stage, M stage, AJCC stage, number of the lymph nodes metastases and the location) were assessed by Kaplan-Meier analysis and multivariate Cox model.Results: In the univariate analysis, AJCC stage (X²=16.206, HR=1.177, P<0.001), N stage (X²=9.536, HR=10.833, P=0.002), T stage (X²=5.810, HR=2.397, P=0.016), number of the lymph nodes metastases (X²=11.423, HR=1.567, P=0.001), and MTV (X²=3.872, HR=2.433, P=0.049) were significant predictors of survival. Multivariate analysis showed that MTV and stage were independent predictors of survival (X²=4.525, HR=1.170, P=0.033; X²=4.875, HR= 3.071, P=0.027). Analysis using Kaplan-Meier curves revealed prolonged survival of low-MTV group as compared to high-MTV group (Log Rank, X²=4.186, P=0.041).Conclusions: In this study, high tumor burden assessed by PET-CT MTV is an independent poor prognostic feature in resectable esophageal squamous cell cancer; MTV is valuable for predicting tumor survival and treatment response. Patients with a high MTV may benefit from more aggressive treatment.