Value of the neoadjuvant chemotherapy with PET/CT metabolic tumor volume (MTV) in advanced gastric cancer of intestinal type

Abstract

Objective To investigate the feasibility and effectiveness of 18 F-FDG PET/CT in neoadjuvant chemotherapy (NAC) response in the patients with resectable advanced gastric cancer of intestinal type.Methods Forty-one patients (28 males and 13 females) with gastric cancer of intestinal type were recruited in this study.All patients received NAC and radical gastric resection,FDG PET/CT was performed before and after NAC and the histopathologic response were detected by postoperative histopathology.The reduction rates of SUVmax and MTV after NAC at primary tumor were calculated and the correlations with histopathologic grades of regression were analyzed using the Spearman correlation analysis.Prediction of pathologic response by SUVmax and MTV was assessed using ROC analysis.x2 test and Z test were also used to analyze the accuracy of Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 and reduction rate of SUVmax for predicting the pathologic response after NAC.Results Twenty patients had effective outcomes according to the histopatholgic response and others didn't.Both of the two metabolic parameters showed significant correlation with the histopathologic grades of regression,while the correlation factor of tumor MTV reduction rate was higher (r=0.763,P＜0.01) than that of SUVmax reduction rate (r=0.434,P＜0.01).The AUC for predicting response was 0.789 with SUVmax reduction rate and 0.943 with MTV reduction rate (Z=2.1 14,P＜0.05).The cutoff value of MTV reduction rate was set to 49.4％ for the highest accuracy for prediction of histopathologic response with a sensitivity of 90.0％ (18/20) and specificity of 90.5％ (19/21).The MTV with PET/CT was a better predictor for histopathologic response than that of RECIST 1.0 criteria (accuracy:90.2％(37/41) vs 80.5％(33/41);x2=7.14,P＜0.05).Conclusions 18F-FDG PET/CT MTV can be used as an important indicator for assessment of NAC response in patients with resectable advanced gastric cancer of intestinal type. Key words: Stomach neoplasms; Drug therapy; Tomography, emission-computed; Tomography, X-ray computed; Deoxyglucose