Hematogenous Tumor Cell Spread Following Standard Transurethral Resection of Bladder Carcinoma

Abstract

Female 94 No tumor 0 0 Female 66 Ta low grade 0 0 Male 64 T1 low grade 0 0 Female 85 Ta high grade 1 0 Male 76 T1 high grade 0 0 Male 84 T2 high grade 0 1 Male 88 T2 high grade 4 5 Male 66 T2 high grade 0 12 Cancer of the urothelium is the second most common urological malignancy. In almost 75% of all newly diagnosed tumors, bladder cancer is non–muscle-invasive (NMIBC) [1]. Prognosis varies considerably; 45% of all patients develop a muscle-invasive tumor over time and up to 78% experience local recurrence [2]. It has been shown that transurethral resection of the bladder (TURB) causes intravesical tumor cell spreading and seeding of identical tumor cell clones in the bladder [3]. Therefore, we hypothesized that TURB causes spreading of tumor cells not only intravesically but also hematogenously. To test this hypothesis, we initiated a small study measuring circulating tumor cells (CTCs) before and after resection to ascertain feasibility for future prospective trials. Eight patients with suspicion of urothelial bladder cancer according to ultrasound and/or cystoscopy were included in the trial. To establish the impact of standard TURB on CTC occurrence, a blood sample was taken immediately before and after TURB. All participants gave written informed consent for use of their blood samples in scientific studies. The CellSearch system has been approved by the US Food and Drug Administration as a diagnostic tool for detecting CTCs in metastatic prostate cancer. Targeting the epithelial cell adhesion molecule, the system is based on immunomagnetic enrichment and fluorescent labeling for semiautomated microscopic cell analysis [4]. The CellSearch system was used to enumerate CTCs in samples taken before and after TURB for each patient. In seven of eight patients, urothelial carcinoma was confirmed by histopathology. Three patients had a T2 tumor, two patients had a T1 tumor, and two patients had a Ta tumor. In two patients with high-grade tumors, CTCs were detected preoperatively, and in the patient with a high-grade T2 tumor, CTCs increased postoperatively. In two patients with muscle-invasive disease, CTCs were detectable after but not before TURB. One of these patients had massive tumor cell dissemination. All patients with