Intralesional Bleomycin Injections for Vascular Malformations: A Systematic Review and Meta-Analysis

Background: Vascular malformations are congenital anomalies of the vascular system. Intralesional bleomycin injections are commonly used to treat vascular malformations. However, pulmonary fibrosis could potentially be a severe complication, known from systemic bleomycin therapy for malignancies. In this study, the authors investigate the effectiveness and safety of bleomycin (A2, B2, and A5) injections for vascular malformations, when possible relative to other sclerosants. Methods: The authors performed a PubMed, Embase, Cochrane Central Register of Controlled Trials, and gray literature search for studies (1995 to the present) reporting outcome of intralesional bleomycin injections in patients with vascular malformations (n ≥ 10). Predefined outcome measures of interest were size reduction, symptom relief, quality of life, adverse events (including pulmonary fibrosis), and patient satisfaction. Results: Twenty-seven studies enrolling 1325 patients were included. Quality of evidence was generally low. Good to excellent size reduction was reported in 84 percent of lymphatic and 87 percent of venous malformations. Pulmonary fibrosis was never encountered. Meta-analysis of four studies on venous malformations treated with bleomycin versus other sclerosants showed similar size reduction (OR, 0.67; 95 percent CI, 0.24 to 1.88) but a significantly lower adverse event rate (OR, 0.1; 95 percent CI, 0.03 to 0.39) and fewer severe complications after bleomycin. Symptom relief, quality of life, and patient satisfaction were reported inadequately. Conclusions: The authors’ data suggest that bleomycin is effective in reducing the size of lymphatic and venous malformations, and leads to a lower adverse event rate and fewer severe complications than other sclerosants. The included literature does not provide evidence that pulmonary fibrosis is a complication of intralesional bleomycin injections. This study represents the “best available” evidence; however, only low- to moderate-quality studies were available. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.