Postoperative cytology in relation to recurrences of superficial bladder tumours.

TNM classification allows only a partial estimation of future tumour behaviour after surgery. More knowledge on malignant potential is needed. Spreading of viable tumour cells during transurethral resection (TUR) and their possible subsequent implantation in the bladder mucosa should be an important factor influencing duration of the tumour-free interval (TFI). A total of 1384 fresh urine samples sequentially taken after surgery from 356 patients were examined in a cytological laboratory. Data analysis confirmed significant differences in TFI between the groups with negative, suspicious and positive cytology. The higher the cytological abnormalities the shorter was TFI, regardless of which histopathological tumour grade has been verified.