FDG-PET parameters as predictors of pathologic response and nodal clearance in patients with stage III non-small cell lung cancer receiving neoadjuvant chemoradiation and surgery

Publication date: Available online 19 April 2017
Source:Practical Radiation Oncology
Author(s): Andrea L. Arnett, Ann T. Packard, Kristin Mara, Aaron S. Mansfield, Dennis A. Wigle, Michael G. Haddock, Sean S. Park, Kenneth R. Olivier, Yolanda I. Garces, Kenneth W. Merrell
ObjectivePathologic complete response (pCR) following neoadjuvant chemoradiation (CRT) is associated with improved outcomes in Stage III NSCLC. Conflicting results exist regarding the value of FDG-PET in predicting pCR. This study evaluated the association between postCRT FDG-PET and pCR utilizing novel FDG-PET parameters.MethodsThis retrospective study included patients with treated with CRT and resection. All underwent pre- and post-CRT FDG-PET imaging. Standard uptake value (SUVmax), standard uptake ratio (SUR), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured.ResultsIn total, 44 patients were included for review. The majority had cT2 disease (59.0%).Median radiation dose was 60Gy (45–70.2Gy). Rate of pCR and near-pCR within the primary lesion was 29.5% and 45.5%, respectively. Average reduction in SUVmax was 9.2, whereas SUR normalized to mediastinum and liver showed mean reductions of 4.7 and 3.5, respectively. No association was found between pCR and either MTV or TLG. Reduction in SUVmax and SUR were significantly associated with increased rate of pCR (p≤0.02). A threshold of >75% decrease in SUR-Liver showed significant association with near-pCR (diagnostic odds ratio [DOR]: 8.3; p=0.007). No correlation was found between nodal FDG-PET parameters and nodal pCR.ConclusionsOur results indicate SUV and SUR have utility in predicting pCR after neoadjuvant CRT. SUR parameters trended toward higher DORs, suggesting improved predictive utility compared to SUVmax. Notably, no association was found with nodal pCR.Furthermore, MTV and TLG changes were not predictive, potentially due to inflammation after full dose radiation, but this warrants further investigation.



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