As more people are surviving breast cancer, more will be given bisphosphonate (BP) for bone metastases—and may be at risk for treatment adverse effects, such as atypical femoral fracture (AFF). Clinicians from Royal Victoria Hospital, Belfast, United Kingdom, describe what they learned in the first reported case of AFF caused by daily ibandronate.
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The patient, a 55-year-old woman, had been diagnosed and treated for breast cancer. Twelve years later, she began having hip and lower back pain and was diagnosed with bony metastatic spread. She was started on hormone-suppressing therapy as well as daily ibandronic acid. Four years later, she began having new lower limb and groin pain. Radiography, bone scans and other tests indicated further metastatic spread to her left femur.
While she was waiting for scheduled radiotherapy, she fell, fracturing her left femur. Radiographs revealed AFF, presumed secondary to her BP therapy rather than metastasis. She underwent intramedullary nail fixation.
Evidence suggests that AFFs are stress fractures, the clinicians say. Repetitive loading on bone can lead to micro cracks, which are even more vulnerable to stress when BPs suppress the normal bone repair process.
Atypical femoral fracture is rare. Most cases have been patients receiving intravenous BP; to the clinicians’ knowledge this is the first report of AFF with an oral BP prescribed for bone metastatic breast cancer. But incidence of AFF grows with prolonged treatment, and the risk is raised with oral dosing, which is much higher in cancer cases, the clinicians note, compared with osteoporosis.
Because patients often have prodromal pain before an overt break, the clinicians suggest asking all oncology patients on BP about pain in thigh, hip, or groin. Bone scans and magnetic resonance imaging may reveal an imminent fracture. The clinicians caution that AFFs can be bilateral, so the opposite side also should be imaged.
Source:
Espey R, Grimes S, Heyburn G, Kealey WD. BMJ Case Rep. 2017;2017. pii: bcr-2016-217489.
doi: 10.1136/bcr-2016-217489.
