Retrograde en bloc resection for non-muscle invasive bladder tumor can reduce the risk of seeding cancer cells into the peripheral circulation

OBJECTIVE: To ascertain whether en bloc resection could reduce the risk of seeding cancer cells into the circulation during the resection of non-muscle invasive bladder cancer (NMIBC). METHODS: Patients with primary NMIBC were enrolled in this prospective study from October 2017 to May 2018. Patients were allocated to receive conventional transurethral resection of the bladder (TURB) or retrograde en bloc resection technique of the bladder tumor (RERBT). Blood samples (1 ml) for circulating tumor cell (CTC) enumeration were drawn from the peripheral vein prior to resection (PV1), immediately after resection of the tumor base (PV2), and at 12 h after resection (PV3). Intra-group comparisons of the changes in the number of CTCs identified among the PV1, PV2, and PV3 blood samples were performed in each group. RESULTS: A total of 21 patients (12 in the RERBT group and 9 in the TURB group) were recruited. For patients receiving TURB, the level of CTCs identified in PV3 was significantly higher than that in PV1 (p = 0.047). However, there was no significant difference in CTC counts before and after resection in the RERBT group. CONCLUSION: RERBT did not increase the number of tumor cells in the bloodstream.