Bone Mineral Density as an Individual Prognostic Biomarker in Patients with Surgically-Treated Brain Metastasis from Lung Cancer (NSCLC)

Simple Summary Bone mineral density (BMD) has been shown to be a relevant imaging biomarker for various chronic debilitating diseases. The present study investigated the prognostic value of preoperative BMD values in patients with surgically-treated brain metastasis (BM) related to non-small-cell lung cancer (NSCLC). BMD values were measured in the first lumbar vertebra (L1) in preoperative CT scans and referenced to age-adjusted reference values. Pathologic BMDs were found to exhibit an impaired median overall survival and increased 1-year mortality in the study cohort, and could therefore aid as easily accessible and relevant biomarkers for prognostic assessment and treatment guidance. Patients with BM are in advanced stages of systemic cancer, which may translate into significant alterations of body composition biomarkers, such as BMD. The present study investigated the prognostic value of BMD on overall survival (OS) of 95 patients with surgically-treated BM related to NSCLC. All patients were treated in a large tertiary care neuro-oncological center between 2013 and 2018. Preoperative BMD was determined from the first lumbar vertebrae (L1) from routine preoperative staging computed tomography (CT) scans. Results were stratified into pathologic and physiologic values according to recently published normative reference ranges and correlated with survival parameters. Median preoperative L1-BMD was 99 Hounsfield units (HU) (IQR 74-195) compared to 140 HU (IQR 113-159) for patients with pathological and physiologic BMD (p = 0.03), with a median OS of 6 versus 15 months (p = 0.002). Multivariable analysis revealed pathologic BMD as an independent prognostic predictor for increased 1-year mortality (p = 0.03, OR 0.5, 95% CI 0.2-1.0). The present study suggests that decreased preoperative BMD values may represent a previously unrecognized negative prognostic factor in patients of BM requiring surgery for NSCLC. Based on guideline-adherent preoperative staging, BMD may prove to be a highly individualized, readily available biomarker for prognostic assessment and treatment guidance in affected patients.