Bladder cancer diagnosis by flow cytometry. Correlation between cell samples from biopsy and bladder irrigation fluid

Results of flow cytometry (FCM) examinations of bladder irrigation specimens were compared with those of FCM examinations of cell suspensions from bladder biopsies of 44 urologic patients. The fluorescent dye, acridine orange (AO), was used to stain DNA and RNA differentially and abnormal urothelial cells were identified by their relative content of nucleic acids. Granulocytes and squamous cells could be distinguished from transitional cells in this procedure, and did not interfere with the analyses. Of 28 patients with papillary carcinoma, carcinoma in situ, and invasive carcinoma 27 were identified through FCM examination of irrigation cytology specimens; the one false-negative result was from a low-grade papillary carcinoma. Of 7 patients with papilloma, FCM examinations of irrigation specimens were positive in 4 and negative in 3. Results of FCM studies of biopsy specimens were in good but not complete agreement with those of irrigation specimens. In several cases, irrigation FCM disclosed tumor stemlines that were not identified in biopsy specimens. Discrepancies of this kind seemed most likely due to differences in sampling. Irrigation FCM seems to be a sensitive method for assessing multiple-site bladder tumors, and may be a useful technique for monitoring the course of conservatively managed bladder tumors.