Clinical value of 18 F-FDG and 18 F-FLT PET/CT for the detection of primary and regional lymph node metastasis of gastric cancer

Abstract

Objective To evaluate the value of 18F-FDG and 18F-FLT PET/CT for the detection of primary and regional lymph node metastasis of gastric cancer.Methods Thirty-seven patients with gastric cancer underwent preoperative 18F-FLT and 18F-FDG PET/CT within one week from March 2011 to April 2013.Postoperative histopathology confirmation was obtained in all patients.The PET/CT images were assessed visually and semi-quantitatively.Two-sample t and x2 tests were analyzed using SPSS 13.0.Results For the detection of primary gastric cancer,the sensitivities of 18 F-FLT and 18 F-FDG PET were 89.2％ (33/ 37) vs 91.9％(34/37),respectively (x2=0.158,P＞0.05).The 18F-FLT SUVmax of 16/37 cases with diffuse-type gastric cancer was significantly higher than that of 21/37 cases with intestinal-type gastric cancer (6.89±1.38 vs 3.79±2.45,t=4.533,P＜0.05) ; while 18F-FDG SUVmaxwas not significantly different between the two subgroups (7.13± 1.97 vs 6.36±2.32,t =1.066,P＞0.05).For the detection of regional lymph node metastasis,the sensitivity,specificity and accuracy of 18F-FLT and 18F-FDG were 64.8％(35/54) vs 88.9％(48/54),97.6％(246/252) vs 82.9％(209/252),91.8％(281/306) vs 84.0％(257/306),respectively (x2 =8.796,30.948,8.854,all P＜0.05).The overall sensitivity,specificity and accuracy by both tracers were 92.6％(50/54),98.8％(249/252) and 97.7％(299/306).Conclusions 18F-FLT might be a better or complementary tracer to 18F-FDG for the detection of diffuse-type gastric cancer.Compared with 18FFDG PET/CT,18F-FLT PET/CT may be less sensitive but more specific and accurate for the detection of regional lymph node metastasis.The overall diagnostic accuracy can be improved by using both tracers. Key words: Stomach neoplasms ; Neoplasm metastasis ; Lymph nodes; Tomography, emission-computed ; Tomography, X-ray computed ; Thymidine; Deoxyglucose