Abstract 5586: Circulating tumor cells as the prognostic marker for non-remission and disease-specific mortality of patients with thyroid cancer

Patients with thyroid cancer usually have good prognosis. However, 15-20% of patients ultimately develop recurrence and disease-related death. In this study, we investigate whether the number of circulating tumor cells (CTCs) expressing either epithelial cell adhesion molecule (EpCAM), podoplanin (PDPN, a marker related to poor prognosis in patients with thyroid cancer), or thyroid-stimulating hormone receptor (TSHR, a marker for thyroid cells) is a prognostic marker for non-remission and disease-specific mortality (DSM) of patients with thyroid cancer. Blood samples were collected from patients (n = 128) after thyroidectomy or radioactive iodide therapy. After enrichment of CTCs by a negative selection PowerMag system, enumeration and subtyping of the CD45-depleted cells were performed by immunofluorescence staining using the antibodies aginst EpCAM, TSHR, and PDPN, respectively. Our data revealed that the number of EpCAM+-CTCs (p < 0.001) and PDPN+-CTCs (p < 0.001), and TSHR+-CTCs (p < 0.001) for patients in the non-remission group (n = 43) was significantly higher when compared to the remission group (n = 85). At the cutoff of 40, 14, and 47 cells/mL for EpCAM+-CTCs, TSHR+-CTCs, and PDPN+-CTCs, the accuracy of the assay was equivalent to 80.4%, 76.6%, and 77.3%, respectively. On the other hand, the number of EpCAM+-CTCs (p < 0.001), PDPN+-CTCs (p = 0.013), and TSHR+-CTCs (p < 0.001) for patients in the DSM group (n = 17) was significantly higher when compared to the patients who survived (n = 111). At the cutoff of 27, 25, and 9 cells/mL for EpCAM+-CTCs, TSHR+-CTCs, and PDPN+-CTCs, the accuracy of the assay was equivalent to 69.5%, 67.2%, and 68.5%, respectively. These data together indicate that CTC testing is worthy to be considered as a routine clinical test to benefit clinical care of patients with thyroid cancer. Citation Format: Ching-Ping Tseng, Jen-Der Lin, Miaw-Jene Liou, Wei-Shan Hung, Hsueh-Ling Hsu, Kong-Kit Leong, Yu-Ting Chen, Ju-Chien Cheng. Circulating tumor cells as the prognostic marker for non-remission and disease-specific mortality of patients with thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5586.