Objectives: We retrospectively analyzed the survival of renal cell carcinoma patients with bone metastases, and identified prognostic factors and a model predictive for survival in these patients.
Methods: Fifty patients with renal cell carcinoma with osseous metastases were treated at Hokkaido University Hospital between 1980 and 2004. The relationship between several clinical features and survival was examined univariately. The Cox proportional hazards model was then used to form a multivariate model.
Results: The median survival time from the diagnosis of bone metastasis was 12 mo, and overall survival at 2 yr was 37%. Clinical features correlated with longer survival in the multivariate analysis were a long interval (24 mo or more) between the diagnosis of kidney cancer and that of osseous metastasis (hazard ratio [HR]: 2.608; 95% confidence interval [CI], 1.031-6.599) and the absence of extraosseous metastases (HR: 2.523; 95%CI, 1.023-6.220). By combining these two favorable factors, renal cell carcinoma patients with osseous metastases could be categorized into two different groups. The median time to death in 20 patients with zero favorable factors (poor prognosis) was 5 mo. On the other hand, 30 patients had one or two favorable factors (good prognosis); the median survival time in this group was 30 mo. There was a significant difference in survival duration between the two groups (p<0.001).
Conclusions: Two prognostic factors predicting survival were identified and used to categorize renal cell carcinoma patients with bone metastasis into two prognostic groups.