Repeated urine cell culture in soft agar: potential role in follow-up of patients with transitional cell carcinoma.

To evaluate the persistence of cells with clonogenic properties in patients being treated for transitional cell carcinoma, 272 urine samples were collected from 75 patients and cultured in a double layer soft agar "cloning" system. The development of colonies was evaluated with growth curves based on repeated colony counting with an Omnicon automated colony counter at regular time intervals. Forty-eight patients had at least one evaluable culture. Comparing the results of colony development in culture with the clinical evaluation of the patients, 9 patients had a histologically proven recurrence preceded or accompanied by tumor colony growth in urine culture. One patient had tumor recurrence with growth negative urine culture (false negative). Fifteen patients have had growth negative urine culture with a negative follow-up (mean 19.5 months). Twenty-one patients have had growth positive urine cell cultures with no recurrence in their follow-up (mean 18.7 months). Although the follow-up times are at present relatively short, the present study suggests that repeated soft agar urine culture of patients with low-grade, low-stage bladder carcinoma may provide a means for identifying those patients at a higher risk for recurrence/progression of their disease.