The Medical Advisor

Abstract Background: Drug repurposing has emerged as a strategy in oncology to identify low-cost, widely available agents with potential anticancer activity. Antiparasitic benzimidazoles (fenbendazole, mebendazole) and the macrocyclic lactone ivermectin have been proposed as adjunctive therapies in breast cancer based on preclinical mechanistic data and anecdotal clinical reports. Interest has grown within integrative oncology communities, particularly for advanced or treatment-resistant disease. Objective: To compile and summarize reported case experiences describing the use of fenbendazole, ivermectin, and mebendazole in patients with breast cancer, and to outline proposed biological mechanisms and current evidence gaps. Methods: Publicly available case reports, patient testimonials, and practitioner-shared clinical narratives involving breast cancer patients who used fenbendazole, ivermectin, or mebendazole were reviewed and categorized by disease stage, concurrent conventiona...