CT Hounsfield Unit value as a Treatment Response Indicator for Spinal Metastatic Lesions in Patients with Non-Small-Cell Lung Cancer

Abstract

Abstract This study aimed to determine the impact of computed tomography (CT)-measured increased Hounsfield unit (HU) values in the spinal metastatic lesions on the overall survival of patients with non-small-cell lung cancer (NSCLC), as well as to analyze the factors associated with HU increase in metastatic bone lesions. A total of 85 patients were included in this study between 2016 and 2021. HU values were evaluated in the metastatic bone lesions at the time of diagnosis of spinal metastasis (baseline), and at 3, 6, and 12 months after diagnosis. Patients were divided into two groups based on the median increase in HU between baseline and after 3 months of treatment in metastatic bone lesions. The Kaplan-Meier method was used to assess overall survival. Based on the median value of HU change (124), 42 and 43 patients were included in the HU responder and non-responder groups, respectively. The median overall survival was significantly longer in the HU responder group than in the HU non-responder group (13.7 vs. 6.4 months, P < 0.001). Multiple linear regression analysis revealed that the use of antiresorptive agents and molecularly targeted therapies were significant factors associated with an increase in HU. HU increase in spinal metastatic lesions after 3 months of treatment correlated with a significantly longer overall survival in patients with NSCLC. Thus, HU measurement may not only serve as an easy and quantitative method to evaluate the treatment response in spinal metastatic lesions, but can also predict the overall survival.