Gingival squamous cell carcinoma induced by zoledronic acid treatmentof breast cancer with brain metastasis: a case report and review of the literature

Zoledronic acid is prescribed to reduce bone resorption and improve bone remodeling and has recently been used to treat breast cancer. A female patient had bone-metastatic breast cancer complicated by osteonecrosis of the jaw and gingival squamous cell carcinoma (SCC) after receiving zoledronic acid. This 28-year-old patient was diagnosed with HER2-positive invasive breast cancer and underwent surgery and radiotherapy. More than 3 years later, she developed brain and skull tumor metastases and received eight cycles of zoledronic acid plus whole-brain radiation therapy and six cycles of combination chemotherapy and zoledronic acid. Eight months later, she had a jaw-related problem and was diagnosed with osteonecrosis of the jaw and gingival SCC in the left jaw. Although the zoledronic acid induced jaw and gingival squamous cell carcinoma, it led to much better overall survival than the average 4-6 months in such patients.