Circulating Tumor Cells Can Indicate The Spread Of Prostate Cancer Through Local Invasion In Addition To Hematogenous Metastasis

Circulating tumor cells (CTC) have been shown to be correlated with metastasis and poor prognosis in prostate cancer, but there are few studies describing the relationship between circulating tumor cells and local invasion in prostate cancer. Our aim was to determine whether circulating tumor cells predicted local invasion before distant metastasis occurs in prostate cancer. Blood samples from 77 treatment-naive patients with prostate cancer were analyzed for CTCs. The CTCs were enriched with 7.5 mL blood using an EpCAM-independent assay and identified using immunostaining-fluorescence in situ hybridization. The number of CTCs was significantly different between the patients with and without local invasion (P < 0.001). The patients with distant metastasis had more CTCs than the patients without distant metastasis (P < 0.001). There was no significant difference in the number of CTCs in the patients with and without lymph node metastasis (P = 0.0079). The patients with 3 CTCs or more per 7.5 mL blood had poorer survival rates and higher hazards ratios (HR). In this study, we demonstrate that the presence of CTCs is associated with not only distant metastasis but also with local invasion.