Flow cytometry of low stage bladder tumors: correlation with cytologic and cystoscopic diagnosis

Flow cytometry examinations (FCM) were carried out on 110 bladder irrigation specimens from 84 urologic outpatients who had had prior conservative treatment for low stage bladder tumors. The specimens were easily obtained, and adequately cellular in all cases. Of 60 examinations on patients with no cytoscopic abnormalities, FCM and conventional cytology were both negative in 30 and both positive in 12 instances; there were 18 with positive FCM and negative cytology. Of 15 instances with cystoscopically benign appearing papillary lesions, FCM and cytology were both negative in three and both positive in three cases; FCM was positive and cytology negative in nine. Of 35 instances with suspicious cystoscopic findings, FCM and cytology were both positive in 19 and both negative in four; FCM was positive and cytology negative in 12. There were no examples of positive conventional cytology and negative FCM. These findings indicate that, after conservative treatment of low stage tumors, FCM of bladder irrigation specimens may be a more sensitive measure of cytologic abnormalities than is conventional cytology. Specimen collection is feasible as part of the routine urologic examination in an outpatient clinic.