Baseline CT QVT (vascular tortuosity) score predicts OS benefit from bevacizumab in 1L metastatic non-squamous NSCLC

In this retrospective biomarker analysis of SWOG S0819 (NCT00946712), QVT (Quantitative Vessel Tortuosity) Score—an automated CT radiomic measure of chaotic tumor vasculature—was derived from baseline scans in treatment-naïve stage IV non-squamous NSCLC treated with carboplatin/paclitaxel with (56%) or without (44%) bevacizumab (n=334). A significant QVT×bevacizumab interaction on overall survival (p=0.007; doubly robust IPTW + covariate adjustment) suggested treatment effect heterogeneity: bevacizumab benefit increased across QVT quartiles, reaching HR=0.40 in Q4 (p=0.0003) versus no benefit in Q1 (HR=0.89, p=0.64). High QVT was strongly adverse without bevacizumab (HR=3.03, p=0.003) but attenuated with bevacizumab (HR=1.71, p=0.079), consistent with anti-VEGF partially “normalizing” a high-risk vascular phenotype; historically, adding bevacizumab to carboplatin/paclitaxel improved OS from ~10.3 to 12.3 months (HR ~0.80) in ECOG 4599, so an HR ~0.40 signal (if real) would be far larger than the average, unselected benefit.