Abstract 368: Detection of circulating tumor cells in peripheral blood of renal cell carcinoma patients is correlated with survival.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Purpose: The aim of this study was to evaluate the clinical relevance of the presence of disseminated tumor cells in peripheral blood [so called circulating tumor cells (CTCs)] for renal cell carcinoma (RCC) patients after a median follow-up time of 81 months. Methods: 233 peripheral blood samples from 154 RCC patients were investigated for the presence of disseminated tumor cells (DTCs) by autoMACS technique and immunocytochemical (ICC) staining of cytokeratin. The frequency of CTCs was analyzed statistically for correlation with relevant clinical data. Results: Two kinds of tumor cells were detected: Those with expression of cytokeratin 8/18 (CK+), but also cells without a detectable CK+ expression, which we called large blue stained cells (Bl+) with a tumor-like morphology. We hypotesized, that the latter cells could be “sleeping” tumor cells. After following the CD45 autoMACS depletion protocol, we identified CTCs in 96 out of 233 peripheral blood samples (41%), which originated from 81 out of 154 (53%) RCC patients. An update to follow up the RCC patients was conducted in 2012. Besides a significant correlation between the detection of CTCs before and after primary tumor resection a significant association with prognosis was found (p < 0.002; Chi-squared test). RCC patients with CK+ CTCs in their peripheral blood had a 5 times risk of tumor-related death compared to patients without these cells. In a Kaplan-Meier-Analysis these results were confirmed (p < 0.001). Patients with large blue stained cells (Bl+) also had a shorter survival time. Conclusion: In summary, for RCC patients, the presence of CTCs was associated with a poor overall survival and significantly correlated with an increased risk of tumor-related death. It is important to evaluate CK+ tumor cells to determine the role of CTCs in tumor behavior and disease progression. Detection of CK+ CTCs in peripheral blood is a significant and independent prognostic factor for renal cell carcinoma patients. Citation Format: Steffen Goebel, Karen Bluemke, Udo Bilkenroth, Axel Meye, Susanne Fuessel, Christine Lautenschlaeger, Andres Melchior, Hans Heynemann, Paolo Fornara, Helge Taubert. Detection of circulating tumor cells in peripheral blood of renal cell carcinoma patients is correlated with survival. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 368. doi:10.1158/1538-7445.AM2013-368