Purpose: One problem in the treatment of urothelial cancers, in particular of upper urinary tract cancers, is multifocal synchronous and/or metachronous tumor development in the heterotopic urothelium. We investigated the abilities of exfoliated cells in the urine of patients with urothelial cancers to colonize and proliferate in vitro.
Materials and methods: Short-term cultures of 129 urine samples obtained from patients with urothelial cancers and 53 samples from healthy volunteers were compared as to the growth potential of urinary-exfoliated cells and clinico-pathological features, in particular tumor localization and evidence of intraluminal tumor recurrence.
Results: Primary cell outgrowth occurred in 112 (86.8%) of the 129 cell cultures from the patients and in 29 (54.7%) of the 53 from the healthy volunteers (p < 0.0001). "Sufficient cell growth" (more than 10(5) cells per flask) was obtained for 77 (59.7%) of the 129 cultures from patients and 7 (13.2%) of the 53 from the healthy volunteers (p < 0.0001). In terms of tumor localization, the rate of sufficient cell growth was significantly higher for patients with upper urinary tract tumor (21/25, 84.0%) than for those with bladder tumor (56/104, 53.8%) (p = 0.0062). Proportional hazard regression analysis showed that only the growth potential of the urinary-exfoliated cells was significantly predictive of intravesical tumor recurrence in patients with superficial bladder tumors (p = 0.011).
Conclusions: The potentials for the colonization and proliferation of urinary-exfoliated cells are associated with intraluminal multifocal tumor recurrence of urothelial cancers.