Detection and Clinical Significance of Circulating Tumor Cells in Patients Undergoing Radical Cystectomy for Urothelial Bladder Cancer

Purpose To evaluate the feasibility and the clinical significance of a PCR assay to detect CK7 mRNA expression in peripheral blood cells of patients undergoing radical cystectomy for clinically nonmetastatic bladder cancer. Patients and methods From 2005 to 2009, 59 patients undergoing radical cystectomy and pelvic lymph node dissection were prospectively investigated. Peripheral blood was collected prior to surgery and a nested PCR assay was developed to identify patients with circulating cells expressing CK7 mRNA. Preoperative, histopathological data and clinical outcome were compared to CK7 findings. Results Cytokeratin 7 expression was detected in 23/59 (38.9%) patients and correlated to T stage and lymph node status. After a median follow-up of 42 months, 29 patients experienced a recurrence, while 36 died. The presence of CK7 positive cells was significantly associated with an increased risk for recurrence and decreased survival as compared with CK7 negative patients (p<0.001 and p<0.001; hazard ratio of 8.77 and 5.2 for recurrence and overall death, respectively). The detection of CK7 positive cells was an independent predictor of recurrence and death in a multivariable analysis. Conclusion The detection of CK7 mRNA in the circulating cells of patients undergoing radical cystectomy for urothelial cancer identifies those with significantly increased risk of cancer recurrence and death.