Negative-predictive value of SUVmax for Ascertaining the efficacy of osimertinib in EGFR mutation-positive non-small cell lung cancer

Background: Fluorine-(18) 2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (F-18-FDG PET/CT) is routinely used to stage non-small cell lung cancer (NSCLC). However, whether F-18-FDG accumulation in primary tumors affects the efficacy of osimertinib in patients with epidermal growth factor receptor (EGFR) mutation-positive NSCLC remains unclear. Methods: We retrospectively investigated 74 patients with advanced or postoperative recurrent EGFR mutation-positive NSCLC who underwent F-18-FDG PET/CT and were treated with osimertinib as first-line therapy between September 2018 and March 2023 at Kumamoto University Hospital. The maximum standardized uptake value (SUVmax) of each primary tumor was measured, and the patients were divided into two groups according to the median SUVmax. The effects of SUVmax on progression-free survival (PFS) and overall survival (OS) were assessed using a multivariate Cox proportional hazards model. Results: The median SUVmax was 8.2 (interquartile range: 5.5-11.4). The median PFS in the high SUVmax group (>= 8.2) was significantly shorter than that in the low SUVmax group (<8.2). The respective median PFSs were 11.2 months (95% confidence interval [CI]: 3.1-19.3 months) vs. 22.9 months (95% CI: 12.4-33.4 months) (P = 0.015), although the OS values did not differ significantly. Multivariate analysis showed that a high SUVmax was an independent negative predictive factor for PFS in patients treated with osimertinib (hazard ratio, 2.25; 95% CI: 1.15-4.39, P = 0.017). Conclusions: High primary-lesion SUVmax in patients with EGFR mutation-positive NSCLC correlated with shorter PFS with first-line osimertinib therapy, suggesting that SUVmax is a useful predictive marker for the antitumor efficacy of osimertinib.