Pulmonary Hemorrhage in Patients Treated With Thoracic Stereotactic Ablative Radiotherapy and Antiangiogenic Agents.

Introduction: Severe pulmonary hemorrhage can occur in patients treated with thoracic stereotactic ablative radiotherapy (SABR) and vascular endothelial growth factor inhibitors (VEGFis). There is limited understanding of which patients are at risk for toxicity with the combination of thoracic SABR and VEGFis or how the risk differs over either therapy alone.

Methods: We evaluated a prospectively maintained cohort of 690 patients with 818 pulmonary tumors treated with highly conformal SABR. Rates of any-grade and grade 3 plus (G3+) pulmonary hemorrhage were compared between patients treated with or without VEGFi therapy across tumor locations. Outcomes were compared between patients treated with SABR plus VEGFi and a propensity-matched cohort of those treated with VEGFi therapy alone.

Results: Treatment with VEGFi plus SABR was associated with higher rates of G3+ pulmonary hemorrhage compared with those treated with SABR alone for the overall cohort (3-y incidence: 7.9% versus 0.6%, p < 0.01) and those with central tumors (19.1% versus 3.3%, p = 0.04). When further subdivided, there were significantly higher toxicity rates with VEGFi for the ultracentral (9.0% versus 45.0%, p = 0.044), but not central nonabutting tumors (0.0% versus 1.3%, p = 0.69). There was an increased incidence of G3+ hemorrhage in patients treated with VEGFi plus SABR compared with VEGFi alone (9.6% versus 1.3%, p = 0.04).

Conclusions: The combination of VEGFi and SABR was associated with an increased risk of high-grade pulmonary hemorrhage over either therapy alone. Low rates of toxicity were observed when excluding patients with SABR to ultracentral tumors and applying highly conformal SABR techniques.