Predicting pathological complete response (pCR) after stereotactic ablative radiation therapy (SABR) of lung cancer using quantitative dynamic [18F]FDG PET and CT perfusion: a prospective exploratory clinical study

Abstract Background Stereotactic ablative radiation therapy (SABR) is effective in treating inoperable stage I non-small cell lung cancer (NSCLC), but imaging assessment of response after SABR difficult. This prospective study aimed to develop a predictive model for true pathologic complete (pCR) using imaging-based biomarkers from dynamic [ 18 F]FDG-PET and CT Perfusion (CTP). Methods Twenty-six patients with early-stage NSCLC treated followed by surgical resection were included, as pre-specified secondary analysis larger study. Dynamic CTP performed pre-SABR 8-week post. provided maximum mean standardized uptake value (SUV) kinetic parameters estimated previously developed flow-modified two-tissue compartment while measured blood flow, volume vessel permeability surface product. Recursive partitioning (RPA) was used establish the PET predicting pCR. The compared current RECIST (Response Evaluation Criteria Solid Tumours version 1.1) PERCIST (PET Response 1.0) criteria. Results RPA identified three groups based on tumour before (BV ) change SUV max (?SUV ), thresholds being BV = 9.3 mL/100 g ?SUV ? 48.9%. highest pCR rate 92% observed group < 48.9% worst ? (0%). achieved excellent prediction (Concordance: 0.92; P 0.03). showed poor 0.54 0.58, respectively). Conclusions In this study, we that significantly better than criteria predict SABR. which correlates microvessel density proliferation, respectively warrants validation sample size studies. Trial registration MISSILE-NSCLC, NCT02136355 (ClinicalTrials.gov). Registered May 8, 2014, https://clinicaltrials.gov/ct2/show/NCT02136355