Renal toxicity and osteonecrosis of the jaw in cancer patients treated with bisphosphonates: a long-term retrospective analysis

Background: Bisphosphonates (BPs) are the mainstay of bone-directed therapy for bone metastases from multiple myelomas and a wide range of solid tumours, but some patients experience renal toxicity or osteonecrosis of the jaw (ONJ). Patients and methods: We reviewed data relating to 398 patients treated with intravenous BP for bone metastases, checking their serum creatinine levels throughout the treatment period in order to assess renal function, and seeking any signs and symptoms of ONJ recorded in their medical records. We also analysed other risk factors for renal toxicity and ONJ in patients who developed them. Results: The median treatment period was 14 months (range 1-119); 108 patients received BP for more than 1 year, and 112 for more than 2 years. Sixteen patients (4%) developed renal toxicity after a median of 24 months of BP treatment, eight of them had been treated for more than 2 years. Ten patients (2.5%) were diagnosed as having ONJ after a median of 39 months on BP, only three of them had been treated for less than 2 years. Two patients experienced both ONJ and renal toxicity. Conclusions: The low incidence of ONJ and renal toxicity indicates the safety of BP. However, prevention and early detection are still the "first-line therapy" for decreasing their occurrence further.