Application Of ¹⁸F-FDG PET/CT In Early Evaluation Of Response To Chemotherapy In Patients With Non-small Cell Lung Cancer

Objective:The relationship between the effect of early metabolism in 18F-FDG PET/CT and the conventional CT based on the RECIST standard to evaluate best objective response after chemotherapy in patients with non-small cell lung cancer(NSCLC)) was discussed to furtherly improve the application value of 18F-FDG PET/CT in early evaluation of response to chemotherapy in non-small cell lung cancer, and provide scientific guidance for clinical. Methods:To collect the patients with unresectable locally advanced or advanced NSCLC which were confirmed pathologically(by bronchoscopy, puncture biopsy or pleural effusion, sputum cytology, etc), the ECOG score from 0 to 1, the expected survival time over 3 months, the lung tumor primary cancer focus could be evaluated according to the RECIST standard, there was no history of diabetes, blood glucose was normal. According to the above standard, there were 40 cases enrolled into this study from September 2009 to December 2014 in Shanxi Province Tumor Hospital, aged from 35 to 78 years old, male 31(77.5%), female 9(22.5%), in 3 patients with unresectable stage ⅢA, 8 cases of stage ⅢB, 29 patients at stage IV, 12 cases of squamous cell carcinoma, 28 cases of adenocarcinoma. Patients were scanned by 18F-FDG PET/CT before and after the first one cycle(three weeks) of chemotherapy(undergo platinum-based doublet chemotherapy), after two cycles of chemotherapy to scan by CT of the chest. If the SUVmax reduction>30% of primary lung cancer after one cycle of chemotherapy, then was regarded as the metabolic remission, if the SUVmax reduction≤30%, it was called metabolic no relief. CT for the effect of chemotherapy to be evaluated in NSCLC according to RECIST standard, i.e. After two cycles of chemotherapy when the effect achieved CR and PR, which was objective and effective, SD and PD was objectively regarded as invalid. The data were analyzed by SPSS19.0 statistical software, the paired chi-square test and kappa test were applied to compare the difference between RECIST best objective response and 18F-FDG PET/CT metabolic response, its consistency, and calculated the 18F-FDG PET/CT to predict best objective response of chemotherapy according to RECIST for NSCLC the sensitivity, specificity, accuracy, positive predictive value and negative predictive value. Using the two-sample t-test to compare the differences of SUVmax reduction between metabolism of remission group and metabolism of non remission group, all statistical methods is 0.05 for the inspection level, P <0.05 was considered statistically significant difference. Results:According to the RECIST standard after two cycles of chemotherapy: 0 case of CR, 17 cases of PR, 19 cases of SD, 4 cases of PD, the rate of objective response was 42.5%(17/40), the rate of disease controlled was 90%(36/40). According to the SUV value after one cycle of chemotherapy: metabolic remission for 23 cases, 17 cases of metabolic no relief, the rate of metabolic remission was 57.5%(23/40). The results showed that:1.There was no difference between RECIST best objective response and 18F-FDG PET/CT metabolic response(χ2 =2.083, P=0.146>0.05), and had a good consistency(Kappa=0.413,P=0.006<0.05).2. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 82%(14/17)、61%(14/23)、70%(28/40)、61%(14/23)and 82%(14/17) respectively.3. Using the two-sample t-test to compare the difference of SUVmax reduction between metabolism of remission group and metabolism of non remission group was statistically significant(P<0.001). Conclusion:1. 18F-FDG PET/CT may predict best objective response to chemotherapy for NSCLC patients.2. Compared with the conventional CT, 18F-FDG PET/CT can be a early and accurate way to evaluate the chemotherapy effect in NSCLC.