[Clinical characteristics and prognosis of renal cell carcinoma patients with bone metastases]

Objective: To determine the status of bone metastasis (BM) and prognosis factors of patients with renal cell carcinoma (RCC) in our center. Methods: The clinical and medical records of RCC patients with BM, who were admitted to the Department of Urology, Bone Oncology and Spine Surgery, Beijing Jishuitan Hospital from August 2009 to August 2017 were collected. The gender, age, time of BM, location of BM, numbers of BM, presence or absence of visceral metastasis, pathological types of BM were investigated. The patients were followed up regularly, and the survival curves were analyzed by Kaplan-Meier method. Cox proportional hazard regression model was used to estimate the prognostic factors. Results: A total of 51 RCC patients with bone metastasis were collected. The age of patients ranged from 38 to 76 (58.6±8.2) years old, including 39 males (76.5%) and 12 females (23.5%). The ratio of male to female was 3.25∶1. The patients were followed up for 8 to 109 months, with a median follow-up time of 30 months. The follow-up rate was 90.2%. Thirty-one (60.8%) patients died at the last follow-up, with a median overall survival (OS) time of 25 months. The median OS was 38 months and 20 months in the solitary BM group (26 cases, 51.0%) and BM ≥ 2 group (25 cases, 49.0%), respectively. The difference between the two groups was statistically significant (P=0.021). The median OS was 30 months, 69 months and 17 months in the axis BM group (22 cases, 43.1%), appendicular BM group (19 cases, 37.3%) and both the axis and appendicular BM group (10 cases, 19.6%), respectively. The difference between the groups was statistically significant (P=0.012). The median OS was 22 months and 38 months in the patients with (15 cases, 29.4%) and without (36 cases, 70.6%) visceral metastases groups, respectively. The difference between the two groups was statistically significant (P=0.007). Univariate and multivariate Cox regression analysis showed that the numbers of BM (HR=3.130, 95%CI: 1.502-6.520, P=0.035) and visceral metastasis (HR=4.699, 95%CI: 1.810-9.545, P=0.001) were independent prognostic factors for RCC with BM. Conclusions: Solitary BM, no visceral metastasis are good prognostic factors for RCC with BM. For these patients, radical resection of BM is feasible to improve survival rate.