Objective <p>Minimally invasive percutaneous cement injection is a valuable palliative method for managing symptomatic pelvic bone metastases in patients with advanced cancer, offering pain relief. However, despite its efficacy, the associated safety profile — particularly the risk of pulmonary cement embolism — is poorly understood. This study aimed to identify the mechanisms and risk factors of pulmonary cement embolism to provide clinical guidance for its prevention.</p> Materials and methods <p>Data from 208 patients who underwent percutaneous cementoplasty for pelvic metastatic lesions between 2008 and 2024 were retrospectively analyzed. After excluding patients who did not undergo perioperative computed tomography (CT, n = 50), 158 patients were enrolled in this study. Data on preoperative factors potentially linked to the vascularity of pelvic metastases and intraosseous pressure during cement injection were collected. From 2021 to 2023, an additional decompression needle was used during cement injection to maintain the intraosseous pressure below 10&#xa0;kPa. Pulmonary cement embolism was assessed using pre- and postoperative CT scans.</p> Results <p>Pulmonary cement embolism occurred in 20 (12.7%) patients. Hypervascular primary cancers, hepatocellular carcinoma, and thyroid cancer, were significantly associated with pulmonary embolism (p = 0.05). Pre-injection radiation therapy showed a protective effect (p = 0.02). No other factors, including intraosseous pressure, were significant.</p> Conclusion <p>Pulmonary cement embolism is more likely related to tumor vascularity than a high intraosseous pressure during cement injection. Thus, when dealing with highly vascular tumors, increased caution is necessary to prevent embolisms. Whenever feasible, radiation therapy should be prioritized over cement injection to reduce the risk of pulmonary cement embolism.</p>