Antiresorptive drugs, which reduce bone breakdown, are an important part of treatment for breast cancer that has spread to the bones. However, their use can be associated with medication-related osteonecrosis of the jaw (MRONJ), a condition in which bone tissue in the jaw dies. In a Finnish registry study, osteonecrosis of the jaw was diagnosed in 12.6% of patients treated with denosumab during long-term follow-up.