Prognostic value of early FDG PET response imaging and peripheral immunologic biomarkers: sub-study of a phase II trial of risk-adaptive chemoradiation for unresectable non-small cell lung cancer

Abstract Introduction We seek to examine the prognostic value of FDG-PET imaging during chemoradiation for unresectable non-small cell lung cancer (NSCLC) for survival and hypothesize tumor PET response is correlated with peripheral T-cell function. Methods 45 patients with AJCCv7 stage IIB-IIIB NSCLC enrolled on a phase II trial and received platinum-doublet chemotherapy concurrent with 6-weeks of radiation (NCT###). FDG-PET was performed prior to treatment start and after 24 Gy of radiation (week 3). PET response status was prospectively defined by multifactorial radiologic interpretation. PET responders received 60 Gy in 30 fractions, while non-responders received concomitant boosts to 74 Gy in 30 fractions. Peripheral blood was drawn synchronously with PET imaging, from which germline DNA sequencing, T-cell receptor (TCR) sequencing, and plasma cytokines analysis were performed. Results Median follow-up was 18.8 months, 1-year overall-survival (OS) 82%, 1-year progression-free survival (PFS) 53%, and 1-year locoregional control (LRC) 88%. Higher mid-treatment PET total lesion glycolysis was detrimental to OS (1-yr 87% vs. 63%, p Conclusions Mid-chemoradiation PET imaging is prognostic for survival; PET response may be linked to tumor and peripheral T-cell biomarkers.