The prognostic effect of pretreatment 18F-FDG PET/CT metabolic parameters in locally advanced Esophageal Squamous Cell Carcinoma treated with definitive chemoradiotherapy.

INTRODUCTION: In this study, we aimed to examine the relation between pre-treatment 18F-FDG PET/CT metabolic parameters [(including the maximum standard uptake value (SUVmax), metabolic tumor volume (MTV), and tumor lesion glycolysis (TLG)] and treatment response and survival in locally-advanced Esophageal Squamous Cell Cancer (ESCC) treated with definitive chemoradiotherapy (dCRT). METHODS: A total 76 patients with locally-advanced ESCC who received dCRT between June 2015 and December 2019 were included in this retrospective study. Patients were divided into two groups as complete response (CR) or non-complete response (Non-CR) according to response to treatment. AUC was obtained as 0.749 (p < 0.001) in the ROC curve drawn by MTV for the CR. The MTV value was ≤12 cm3, with 72.1% sensitivity and 73.0% specificity. RESULTS: Of the 76 patients, 38 (50%) were male and 38 (50%) were female. The median age was 62 (39-84) years. The treatment response in 35 (46%) patients was CR. MTV value was >12cm3 in 41(54%) patients. Median follow-up time was 14.5 months. In patients with MTV>12cm3, median progression-free survival(mPFS) and median overall survival(mOS) were 9 months and 11 months, respectively, whereas mPFS and OS could not be reached in those with MTV≤12 cm3 (p < 0.001 and p < 0.001, respectively). In patients with non-CR, mPFS and mOS were 8 months and 9 months, respectively, whereas mPFS and OS could not be reached in patients with CR (p < 0.001 and p < 0.001, respectively). In multivariate analysis, age (odds ratio [OR], 1.07), ECOG PS (OR, 11.1), and MTV (OR, 4.73) were found to be the factors affecting treatment response. CONCLUSION: In our study, treatment response and MTV were found to be the factors associated with survival in patients treated with dCRT, showing the pre-treatment MTV value as a predictor of treatment response.

Texture features of primary tumor on 18F-FDG PET images in non-small cell lung cancer: The relationship between imaging and histopathological parameters.

PURPOSE: The aims of this study were to evaluate the relationships between textural features of the primary tumor on FDG PET images and clinical-histopathological parameters which are useful in predicting prognosis in newly diagnosed non-small cell lung cancer (NSCLC) patients. METHODS: PET/CT images of ninety (90) patients with NSCLC prior to surgery were analyzed retrospectively. All patients had resectable tumors. From the images we acquired data related to metabolism (SUVmax, MTV, TLG) and texture features of primary tumors. Histopathological tumor types and subgroups, degree of Ki-67 expression and necrosis rates of the primary tumor, mediastinal lymph node (MLN) status and nodal stages were recorded. RESULTS: Among the two histologic tumor types (adenocarcinoma and squamous cell carcinoma) significant differences were present regarding metabolic parameters, Ki-67 index with higher values and kurtosis with lower values in the latter group. Textural heterogeneity was found to be higher in poorly differentiated tumors compared to moderately differentiated tumors in patients with adenocarcinoma. While Ki-67 index had significant correlations with metabolic parameters and kurtosis, tumor necrosis rate was only significantly correlated with textural features. By univariate and multivariate analyses of the imaging and histopathological factors examined, only gradient variance was significant predictive factor for the presence of MLN metastasis. CONCLUSIONS: Textural features had significant associations with histologic tumor types, degree of pathological differentiation, tumor proliferation and necrosis rates. Texture analysis has potential to differentiate tumor types and subtypes and to predict MLN metastasis in patients with NSCLC.