Circulating tumor cell counts in patients with localized prostate cancer including those under active surveillance

Abstract

Aim: To evaluate the clinical efficacy of a circulating tumor cell (CTC) test by comparison between healthy volunteers and patients with localized prostate cancer including those under active surveillance. Materials and Methods: CTC counts in peripheral blood were compared between patients with prostate cancer (n=45) and healthy volunteers (n=17). CTCs were identified based on the expression of epithelial cell adhesion molecule (EpCAM) and counted using a SMART BIOPSY™ SYSTEM. Results: The number of EpCAM+ cells was significantly higher in patients with cancer than in healthy volunteers. Among the low-risk patients (n=9), two had up-staging and six had up-grading. Among those up-staged, there was one case which was EpCAM+. Among those cases up-graded, three were EpCAM+. In those with stage T2 tumors, the presence of Gleason pattern 5 was positively correlated with EpCAM positivity (rho=0.59, p<0.001). Conclusion: CTC counts in localized prostate cancer were associated with Gleason pattern 5. Active treatment should be considered for patients with low-risk disease during active surveillance who are found to have EpCAM+ CTCs because of a risk of up-staging and upgrading.