Clinical Features and Prognostic Factors of Metastatic Non-Clear Cell Renal Cell Carcinoma: A Multicenter Study from the Turkish Oncology Group Kidney Cancer Consortium.

INTRODUCTION: We aimed to evaluate clinical features, prognostic factors, and treatment preferences in patients with non-clear cell renal cell carcinoma (nccRCC).

METHODS: Patients with metastatic nccRCC were selected from the Turkish Oncology Group Kidney Cancer Consortium (TKCC) database. Clinical features, prognostic factors, and overall survival (OS) outcomes were investigated.

RESULTS: A total of 118 patients diagnosed with nccRCC were included in this study. The median age at diagnosis was 62 years (interquartile range: 56-69). Papillary (57.6%) and chromophobe tumors (12.7%) are common histologic subtypes. Sarcomatoid differentiation was present in 19.5% of all patients. When the patients were categorized according to the International Metastatic RCC Database Consortium (IMDC) risk scores, 66.9% of the patients were found to be in the intermediate or poor risk group. Approximately half of the patients (55.9%) received interferon in the first line. At the median follow-up of 53.2 months (95% confidence interval [CI]: 34.7-71.8), the median OS was 19.3 months (95% CI: 14.1-24.5). In multivariate analysis, lung metastasis (hazard ratio [HR]:2.22, 95% CI: 1.23-3.99) and IMDC risk score (HR: 2.35, 95% CI: 1.01-5.44 for intermediate risk; HR: 8.86, 95% CI: 3.47-22.61 for poor risk) were found to be independent prognostic factors.

CONCLUSION: In this study, survival outcomes are consistent with previous studies. The IMDC risk score and lung metastasis are the independent prognostic factors for OS. This is an area that needs research to better treat this group of patients and create new treatment options.