Abstract 1728: CTCs and CTM as prognostic factors in sarcoma patients

Abstract

Abstract Background: Sarcomas represent 1% of all cancers in adults, 8% in adolescents and young people, and 10% in children. Even though it is a rare cancer, it contributes to a significant loss of years of life in comparison with other types of cancer (Amankwah, et al., 2013). The presence of isolated Circulating Tumor Cells (CTCs) or Circulating Tumor Microemboli (CTM) in the blood of patients with sarcoma may be early markers of tumor invasion, because it is known that these cells circulate in the blood for months or years before the development of metastases (Paterlini-Brechot and Benali, 2007; Klain, 2009; Rhim et al., 2012). Objective: To isolate and quantify CTCs and CTM from sarcoma patients, evaluating their presence and correlation with progression free survival (PFS). Methods: The blood (approximately 8mL) was prospectively collected from patients with different types of high degree sarcoma. Blood was collected before the beginning of chemotherapy. The samples were processed and filtered on ISET (Isolation by Size of Epithelial Tumor Cells, Rarecells, France) system for the isolation and quantification of CTCs and CTMs. Later, was performed immunocytochemistry (ICC) with anti-CD45 antibody and counterstained with hematoxylin-eosyn for leucocytes population exclusion. The cutoff was estimated using the maximum of the standardized log-rank statistic proposed by Lausen & Schumacher (1992). Results: we analyzed 11 high degree sarcoma patients before the beginning of treatment (any treatment line). The median age was 53 years-old (18-77) and 54,5% were male. The median CTCs number was 2.0 CTCs/mL (1.0-11.0) at baseline. By Kaplan-Meier test, we observed that patients with CTC number below the established cutoff (4.5 CTCs/mL) had better PFS compared to those above the cutoff (7.4 vs. 1.0 months respectively; P= 0.006). Moreover, patients without CTM had also better PFS compared to those patients with the presence of CTM (7.6 vs. 2.7 months respectively; P= 0.13). Conclusion: this is the first study to demonstrate, besides the CTC and CTM presence in sarcoma patients, its real prognostic value, even in a limited sample. Our next step is to characterize these cells to better understand its capability to promote tumor progression. Citation Format: Alexcia C. Braun, Celso A. Mello, Marcelo P. Corassa, Vanessa S. Alves, Emne A. Abdallah, Ulisses R. Nicolau, Mônica Taiane de Macedo Díaz, Bianca de Cássia Troncarelli de Campos Parra Flores, Marcelo F. Fanelli, Patrizia Paternili-Brechót, Ludmilla T. Chinen. CTCs and CTM as prognostic factors in sarcoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1728. doi:10.1158/1538-7445.AM2017-1728