Please use this link to access this publication. Abstract Introduction: Aromatase inhibitors (AIs) are commonly used for postmenopausal women with hormone receptor-positive breast cancer. Nearly two-thirds of women on AIs have arthralgias, joint stiffness, and/or bone pains referred to as aromatase inhibitor-induced musculoskeletal syndrome (AIMSS), leading to poor adherence. Preclinical and clinical data suggest topical cannabinoids can reduce inflammation in arthritis. Materials and Methods: We conducted a randomized trial assessing feasibility, tolerability, and preliminary efficacy of topical cannabis for women with stage 1–3 breast cancer experiencing AIMSS. Women were randomized 1:1 to cannabidiol (CBD) vs. delta-9-tetrahydrocannabinol (THC) balms. The balm was applied three times daily to...