Oligometastatic state predicts a favorable outcome for renal cell carcinoma patients with bone metastasis under the treatment of sunitinib

BACKGROUND The aim of the study was to investigate whether RCC patients with oligometastatic state of bone metastasis treated with sunitinib had a favorable clinical outcome. RESULTS 22 patients were classified into oligometastatic state of bone metastasis with a median OS of 30.1 months (95%CI: 26.3 to 33.8 months). The 45 patients with non-oligometastatic state had a median OS of 12.7 months (95%CI: 9.43 to 16.0 months). Kaplan-Meier analysis showed significant difference between them (Log Rank test p<0.001). When we set patients with only multiple bone (at least 5 sites) metastases as a single group, there was still significant difference between oligometastatic state group and non-oligometastatic state groups. In multivariate Cox proportion hazard ratio analysis, metastatic states (p=0.012), MSKCC score (p=0.002), ECOG (p=0.001) and lymph nodes metastasis (p=0.000) were significantly associated with prognosis. The integration of metastatic state into the MSKCC risk model improved the c-index from 0.651 to 0.752. METHODS 67 patients from Fudan University Shanghai Cancer Center with bone metastatic RCC were divided into 2 metastatic states. One included those with oligometastatic state of bone metastasis with less than 5 sites of bone metastasis. The other involved those patients with multiple bone metastases (at least 5 sites) or together with other sites of metastasis. Then patients with only multiple bone (at least 5 sites) metastases were set into a single group. CONCLUSIONS RCC patients with oligometastatic state of bone metastasis treated with sunitinib had a favorable clinical outcome.