[Cytology by lavage in the follow-up of bladder neoplasms]

We evaluated the results of urinary cytology, obtained from bladder washing, in the follow-up of patients with superficial bladder tumors. For the study, we used 545 samples. These were compared with the cystoscopic findings when cytology was negative, and with the biopsy findings when positive. We observed that the sensitivity of cytology increased with tumor grade, stage and number. The highest sensitivity rate was observed for carcinoma "in situ". However, a low specificity rate was observed for single, low grade/stage lesions. False-positives diminished inversely with cytologic grading, which was only 8% for cytology grade 3. There were more false-positives in patients that were on prophylactic therapy with thiotepa. The foregoing increased with the duration of treatment. Bladder lithiasis, abacterial cystitis, urinary infection, adenoma and prostatic cancer found to yield falsely positive results. False-negatives appeared principally in single, low grade/stage tumors. We underscore the low number of false-negatives observed in patients on thiotepa or those with bladder diverticulum. Follow-up of patients with true-negative or false-positive cytology showed a higher incidence and earlier tumor recurrence in the latter patient group. We discuss all the foregoing findings and present a protocol for patient follow-up.