Clinical characteristic and survival analysis of distant metastatic sarcomatoid renal cell carcinoma: A study of 378 patients

Objective: To analyse the clinical characteristic and survival of distant metastatic sarcomatoid renal cell carcinoma(sRCC), compare the differences between single lung metastases and single bone metastases, and identify the prognostic factors for distant metastatic sRCC patients. Methods: : Data from the SEER database between 2004 and 2016 were analyzed, overall survival (OS) between different groups were compared by the Kaplan-Meier method and the Log-rank test, prognostic factors associated with OS were identified by univariate and multivariate Cox proportional hazards models. Results: : Among the 378 patients with distant metastatic sRCC, 128 were single lung metastases(33.86%), 66 were single bone metastases(17.47%), 59 were “lung + bone” metastases(15.60%), and the total number of other sites of metastases was 125(33.07%).Patients with single lung metastases had a higher proportion of T3 and T4 stages than those with single bone metastases( P ＜0.001).The median OS of 378 patients was 4 months, and there was no statistically significant difference in OS between patients with single lung metastases and single bone metastases (χ2=4.643, P = 0.200). Surgery(cytoreductive nephrectomy) and chemotherapy were good prognostic factors for patients with distant metastatic sRCC regardless of sites of metastases , as well as for patients with single lung metastases,while chemotherapy was not found to affect the OS of patients with single bone metastases. Conclusion: Distant metastatic sRCC had a very poor prognosis, single lung metastases and single bone metastases were main metastatic sites and had different characteristics and prognostic factors,patients should receive specific treatment and management.