Histological grading of transitional cell tumours of the bladder. Value of histological grading (WHO) in prognosis.

Mortality among 139 patients with transitional cell tumour of the bladder was studied. Tumours were reevaluated according to the grading system recommended by WHO. The absolute 5-year survival of histologically benign papilloma cases was 68%, of grade I carcinoma cases 64%, of grade II carcinoma cases 42% and of grade III carcinoma patients 34%. Clinical staging (UICC), however, would have been more effective than histological grading (WHO) for prognostic purposes. 3 of the 14 patients with histologically benign papilloma in this study developed grade I carcinoma during follow-up periods of between 4.5 and 24 years. Following radical treatment all recurrences were papillomas. The study suggests that histological grading should be used to complement clinical staging in prognosis and that with half-yearly check-ups and elimination of any tumours thus detected, patients with papilloma rarely develop carcinomas of higher grade than grade I.