Baseline total metabolic tumour volume on 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography-computed tomography as a promising biomarker in patients with advanced non-small cell lung cancer treated with first-line pembrolizumab.

Abstract

INTRODUCTION\nImmune checkpoint inhibitors (ICIs) have become the standard of care in the management of advanced non-small cell lung cancer (NSCLC). Nevertheless, only a small proportion of patients benefit from ICIs. The aim of the present study is to assess whether 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography-computed tomography ([18F]FDG-PET/CT)-derived parameters may be used as biomarkers in patients with advanced NSCLC receiving first-line pembrolizumab.\n\n\nMATERIALS AND METHODS\nThis is a monocentric retrospective cohort study including patients with advanced NSCLC (stage IV) and Programmed death-ligand 1 (PD-L1) expression ≥50% treated with pembrolizumab. A control group of patients treated with epidermal growth factor receptor (EGFR) inhibitors for EGFR-mutated NSCLC was also enrolled. Only patients with a positive [18F]18F-FDG PET/CT result within 60 days from treatment initiation were included.Total metabolic tumour volume (tMTV) was calculated for each lesion using a dedicated software (PET VCAR; GE Healthcare), which semiautomatically delineates the tumour s contours with a maximum standardised uptake value (SUVmax) threshold of 42% within the lesion. tMTV was obtained summing each lesion s MTV. Potential prognostic parameters for overall survival (OS) were analysed (tMTV, SUVmax, bone/liver metastasis, neutrophil:lymphocyte ratio\xa0≥4, Eastern Cooperative Oncology Group performance status\xa0≥2, lactate dehydrogenase\xa0above the upper limit of normal).\n\n\nRESULTS\nOverall, 34 patients treated with first line-pembrolizumab and 40 patients treated with EGFR tyrosine kinase inhibitors were included. In the pembrolizumab group, the median follow-up was 20.3, while the median OS was 4.7 months (95% confidence interval [CI]\xa0=\xa00.3-9.1) for patients with tMTV\xa0≥75\xa0cm3 vs not reached (NR) for patients with tMTV\xa0<75\xa0cm3 (95% CI\xa0=\xa0NR-NR; hazard ratio [HR]\xa0=\xa05.37; 95% CI\xa0=\xa01.72-16.77; p\xa0=\xa00.004). No difference was found in the control group (HR\xa0=\xa01.43; 95% CI\xa0=\xa00.61-3.34; p\xa0=\xa00.411).\n\n\nCONCLUSION\nOur data suggest\xa0that tMTV ≥75cm3 can be used as a prognostic biomarker of poor outcomes in patients with PD-L1-high advanced NSCLC treated with first-line pembrolizumab. This information could be useful for the selection of patients who may require the addition of chemotherapy to pembrolizumab.