Metastatic ER-positive breast cancer complicated by osteonecrosis of the jaw

What happened, in summary

At age 73, a woman had a history of a T2N1 grade 3, estrogen-receptor-positive cancer of the right breast diagnosed in 2008. She underwent right mastectomy with axillary-node sampling, received adjuvant radiation, and began anastrozole. A prior left-breast cancer and a separate non-metastatic renal cell carcinoma were managed independently.

In 2011, bone metastases developed. Anastrozole was changed to exemestane, and monthly zoledronic acid was used to reduce skeletal complications. A pathological fracture of the sternum was treated with palliative radiation. Zoledronic acid was later replaced by denosumab. Further progression led to radiation to T8–T12, changes among tamoxifen, letrozole, and later megestrol acetate, and additional radiation to the cervical spine.

After dental extractions, exposed bone in the mandible failed to heal. She developed pain, halitosis, draining fistulas, infection, and extensive necrosis involving the mandible and part of the maxilla. The condition was attributed to prolonged exposure to zoledronic acid and denosumab. Denosumab was stopped, while letrozole continued. Chlorhexidine, antibiotics, pain medicines, and wound dressings were used, but reconstructive surgery and chemotherapy were considered unsafe because of poor performance status, extensive necrosis, and infection risk.

Her bone metastases progressed through the spine, pelvis, and proximal femur. She was later admitted with sepsis, malignant hypercalcemia, acute kidney injury, and worsening jaw destruction. Palliative care arranged discharge to a nursing home for end-of-life care, and she died three weeks later.