Characterization of bone metastases in patients with renal cell cancer

OBJECTIVE: To characterize the clinical features of bone metastases in patients with renal cell carcinoma (RCC) treated with interleukin-2 therapy. Bone lesions contribute to significant morbidity and mortality, and although present in up to half of patients with RCC, their behaviour and response to therapy have not been well characterized. PATIENTS AND METHODS: We evaluated skeletal metastases in 19 patients with bone lesions who received either moderate- or high-dose interleukin-2 therapy. Data on bone disease, including location and number of bone lesions, need for bone-specific therapies and use of pain medications, were noted. The response of bone lesions to interleukin-2 was compared with the response of other systemic metastatic sites. RESULTS: Skeletal metastases resulted in significant morbidity by causing pain (75%) and other complications requiring surgical and/or radiotherapeutic intervention (94%) before beginning interleukin-2 therapy. In most patients the response of bone lesions to interleukin-2 was similar to that in their other systemic sites. Treatment with interleukin-2 had no significant effect on the requirement for pain medication for bone pain. However, it may have prevented skeletal complications requiring surgery or radiotherapy. None of the patients had hypercalcaemia; there was no significant association between bone metastases and elevated alkaline phosphatase levels. CONCLUSIONS: Skeletal metastases are a significant contributor to morbidity among patients with RCC. Bone lesions respond similarly to interleukin-2 therapy as other systemic sites. Bisphosphonates appear promising for these predominantly osteolytic lesions.