Abstract
BackgroundStereotactic body radiotherapy (SBRT) demonstrates excellent local control in early stage lung cancer, however a quarter of patients develop recurrence or distant metastasis. Transforming growth factor-beta (TGF-β) supports metastasis and treatment resistance, and angiotensin receptor blockade (ARB) indirectly suppresses TGF-β signaling. This study investigates whether patients taking ARBs while undergoing SBRT for early stage lung cancer exhibited improved overall survival (OS) or recurrence free survival (RFS) compared to patients not taking ARBs. MethodsThis was a single institution retrospective analysis of 272 patients treated with SBRT for early stage lung cancer between 2009-2018. Patient health data was abstracted from the electronic medical record. OS and RFS were assessed using Kaplan-Meier method. Log-rank test was used to compare unadjusted survival between groups. Univariable and multivariable Cox proportional hazard regression models were used to estimate hazard ratios (HRs). ResultsOf 247 patients analyzed, 24 (10%) patients took ARBs for the duration of radiotherapy. There was no difference in mean age, median tumor diameter, or median biologic effective dose between patients taking ARBs or not. Patients taking ARBs exhibited increased OS (ARB=96.7 mo.; no ARB= 43.3 mo.; HR=0.25 [95% CI: 0.10 to 0.62, P = .003]) and increased RFS (median RFS, ARB=64.3 mo.; No ARB=35.1 mo.; HR=0.26 [95% CI: 0.10 to 0.63, P = .003]). These effects were not seen in patients taking angiotensin converting enzyme inhibitors (ACEIs) or statins. ConclusionsARB use while undergoing SBRT for early stage lung cancer may increase OS and RFS, but ACEI use does not show the same effect.