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

• Published in: Radiation oncology (London, England) England), 2021-01, Vol.16 (1), p.11-8, Article 11
• Main Authors: Yang, Dae-Myoung, Palma, David A, Kwan, Keith, Louie, Alexander V, Malthaner, Richard, Fortin, Dalilah, Rodrigues, George B, Yaremko, Brian P, Laba, Joanna, Gaede, Stewart, Warner, Andrew, Inculet, Richard, Lee, Ting-Yim
• Format: Article
• Language: English
• Subjects: [18F]FDG; Ablation; Biomarkers; Blood; Blood flow; Blood vessels; Blood volume; Cancer therapies; Cell proliferation; Computed tomography; Criteria; CT perfusion; Dynamic positron emission tomography (PET); Fluorine isotopes; Lung cancer; Medical imaging; Metabolism; Non-small cell lung cancer (NSCLC); Non-small cell lung carcinoma; Parameter estimation; Parameter modification; Pathologic complete response (pCR); Patients; Perfusion; Permeability; Positron emission; Positron emission tomography; Prediction models; Pulmonary arteries; Radiation; Radiation therapy; Scanners; Secondary analysis; Small cell lung carcinoma; Solid tumors; Stereotactic ablative radiation therapy (SABR); Surgery; Tomography; Tumors
• ISSN: 1748-717X; 1748-717X
• DOI: 10.1186/s13014-021-01747-z

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 is difficult. This prospective study aimed to develop a predictive model for true pathologic complete response (pCR) to SABR using imaging-based biomarkers from dynamic [ F]FDG-PET and CT Perfusion (CTP). Twenty-six patients with early-stage NSCLC treated with SABR followed by surgical resection were included, as a pre-specified secondary analysis of a larger study. Dynamic [ F]FDG-PET and CTP were performed pre-SABR and 8-week post. Dynamic [ F]FDG-PET provided maximum and mean standardized uptake value (SUV) and kinetic parameters estimated using a previously developed flow-modified two-tissue compartment model while CTP measured blood flow, blood volume and vessel permeability surface product. Recursive partitioning analysis (RPA) was used to establish a predictive model with the measured PET and CTP imaging biomarkers for predicting pCR. The model was compared to current RECIST (Response Evaluation Criteria in Solid Tumours version 1.1) and PERCIST (PET Response Criteria in Solid Tumours version 1.0) criteria. RPA identified three response groups based on tumour blood volume before SABR (BV ) and change in SUV (ΔSUV ), the thresholds being BV  = 9.3 mL/100 g and ΔSUV  = - 48.9%. The highest true pCR rate of 92% was observed in the group with BV