Tumor necrosis or cavity on baseline CT scan as a negative predictive biomarker for immune checkpoint inhibitors in advanced lung squamous cell carcinoma.

Abstract

e20556 Background: Current predictive biomarker for immune checkpoint inhibitors (ICIs) does not distinct according to histologic subtype. We hypothesize that necrosis or cavity on baseline CT scan in lung squamous cell carcinoma (LSCC) is predictive of treatment for ICIs. Methods: This was a multicenter retrospective analysis of patients with advanced LSCC. All eligible patients must had received either first-line chemotherapy only (chemotherapy group), or ICIs as monotherapy or combined with chemotherapy (ICIs group). Radiotherapy to thorax was not allowed. Baseline contrast-enhanced CT were reviewed by independent radiologist in each center. Radiologic finding was correlated with outcomes. Results: Total of 538 patients were eligible with 270 patients in the chemotherapy group and 268 patients in ICIs group. Baseline characteristics were well balanced. Tumor necrosis or cavity was identified in 111 (41.1%) in chemotherapy group and 99 (36.9%) in ICIs group. In chemotherapy group, there was no difference in PFS between patients with or without necrosis or cavity (5.33 vs 4.97 months, Hazard Ratio (HR) 1.05, 95% confidence interval (CI), 0.81-1.36, p= 0.726). In contrast, there was significant difference in PFS in ICIs group favoring patients without tumor necrosis or cavity (8.7 vs 6.5 months, HR 0.67, 95% CI 0.42–0.63, p< 0.001). Multivariate Cox analysis confirmed necrosis or cavity as an independent unfavorable predictive factor for PFS (HR 0.68; 95% CI, 0.51-0.9; p= 0.007). Conclusions: Tumor necrosis or cavity on baseline chest CT scan is a promising predictive biomarker for ICIs in LSCC, and this observation warrant further investigation.