[Diagnostic value of flow cytometry of bladder lavage in the surveillance of bladder tumors].

DNA index and proliferation index (% greater than 2 n) of 125 bladder washings were studied with flow cytometry. Cystoscopy was positive in 49 patients and negative in 56 patients with a previous history of bladder cancer. There were 20 control patients with a normal bladder. Flow cytometric data was compared with cystoscopic and cytologic data. In the group of 49 patients with a positive cystoscopy, conventional cytology was suspicious or positive in 70% (34/49) whereas flow cytometry was positive in only 43% of the cases (21/49). The diagnostic sensitivity of flow cytometry increased with grade elevation: 7% of grade 1 tumors, 43% of grade 2 and 77% of grade 3 had a positive flow cytometric examination. In the group of 56 patients with a negative cystoscopy, flow cytometry was positive in 36% of the cases and cytology in 6% of the cases. The diagnostic sensitivity of flow cytometry was rather disappointing in the study on bladder washings. Flow cytometric follow-up of bladder washings should be reserved preferentially to patients with a poor prognosis, i.e., superficial bladder cancer with an aneuploid DNA content.