¹⁸F-FDG PET/CT Predict Short-term Outcome Early In The Course Of Chemoradiotherapy In Stage ? Adenocarcinoma Of Lung

Objective: The aim of this study is to investigate the role of standard uptake values,metabolic tumor volume and total lesion glycolysis in ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography to predict the short-term outcome of chemoradiotherapy in patients with stage III adenocarcinoma of lung.Methods: This is a prospective study of 22 consecutive patients with locally advanced non-small cell lung cancer?NSCLC??stage IIIA/IIIB?who were treated with concurrent chemoradiotherapy in Shandong Cancer Hospital affiliated to Shandong University from March 1st in 2015 until August 31 st in 2016.All patients were evaluated by ¹⁸F-FDG PET/CT before and following 60 Gy radiotherapy with a concurrent cisplatin/pemetrexed chemotherapy regimen,which were administered every 21 days for a total of four to six cycles.Semiquantitative assessment was used to determine maximum and mean SUVs?SUVmax/SUVmean?,metabolic tumor volume?MTV?and total lesion glycolysis?TLG?.Short-term outcome was assessed according to the Response Evaluation Criteria in Solid Tumors based on the CTs which were carried out before the treatment and four weeks after chemoradiotherapy.Statistical significant differences of unpaired quantitative parameters were analyzed by the t test or non-parametric test.All P values were two-sided,and P value less than 0.05 were considered statistically significant.Results: The differences of SUVmax,SUVmean,CEA,CT values,MTV and TLG at baseline PET/CT scans between the responders and the nonresponders were not significant?all P>0.05?.In the responders,the SUVmax fell from 11.67?±6.45?to 5.08?±3.14?after initial concurrent chemoradiotherapy.In nonresponders,this fell from 11.75?±3.48?to 9.67?±5.49?.There was a mean reduction in SUVmax of 47.96% and 17.15% in responders and nonresponders,respectively.The SUVmax of post-treatment was significantly different between responders and nonresponders?P=0.009?.And the change rate before and after treatment of SUVmax??SUV?was significantly different,too,P=0.011.In the responders,the MTV fell from 60.08?±46.21?to 7.86?±8.77?after initial concurrent chemoradiotherapy.In nonresponders,this fell from 102.13?±98.25?to 60.18?±19.51?.There was a mean reduction in MTV of 70.62% and 17.03% in responders and nonresponders,respectively.The change rate before and after treatment of MTV??MTV?was significantly different,P=0.016.In the responders,the TLG fell from 202.30?±2.43?to 29.88?±38.75?after initial concurrent chemoradiotherapy.In nonresponders,this fell from 407.49?±5.85?to 286.59?±4.97?.There was a mean reduction in TLG of 75.56% and 23.00% in responders and nonresponders,respectively.The change rate before and after treatment of TLG??TLG?was significantly different,P =0.034.The thresholds of post-SUVmax,?SUVmax,?MTV and ?TLG defined by ROC curve analysis were 8.6,25.6,38.1 and 49.3,respectively.The ?MTV and ?TLG predicted treatment response?AUC=0.568 and 0.568 respectively?less accurately than did post-SUVmax and ?SUVmax which predicted treatment response heavily?AUC=0.889 and 0.844?.Conclusion: In conclusion,the study proved that ¹⁸F-FDG PET/CT can predict short-term outcome early in the course of chemoradiotherapy in stage ? adenocarcinoma of lung which showed that post-SUVmax,?SUVmax,?MTV and ?TLG had differentiate the responders from nonresponders after the concurrent chemoradiotherapy.The ?MTV and ?TLG predicted treatment response less accurately than did post-SUVmax and ?SUVmax which predicted treatment response heavily.Based on the result,it may help to decide whether additional dose escalation is needed and would allow adequate time to design a boost treatment without requiring a break in therapy.