The efficacy of urinary cytology in the detection of recurrent bladder tumours.

In a prospective study, 71 patients with superficial transitional cell carcinoma of the bladder were given topical immunotherapy with bacillus Calmette-Guerin after transurethral resection and the impact of cystoscopy and bladder wash-out cytology in assessment of recurrent tumours was investigated. Sixteen recurrences were noted histopathologically during the follow-up and 15 of them were also diagnosed properly by wash-out cytology (sensitivity 93.8%). During the follow-up, 10 patients had positive cytology results without evidence of recurrent tumour and 6 of them had recurred cystoscopically in 3 months' time. However, the remaining 4 patients were still tumour-free cystoscopically after a follow-up of 6 months (specificity 92.7%, positive predictive value 78.9%). Although, some false-positive results may be obtained by urine cytology after topical immunotherapy, urine cytology seems to be a reasonable alternative to more invasive and expensive methods during the follow-up of bladder tumours.