Value of random mucosal biopsies in the management of superficial bladder cancer.

115 newly diagnosed patients with Ta-T1, G1-G2 superficial transitional cell carcinoma of the bladder underwent four quadrant biopsies of normal-looking bladder mucosa, in addition to the endoscopic treatment of the primary tumour or tumours. In 88 (77%) patients all the biopsies were normal; in the other 27 (23%) at least one biopsy revealed dysplasia or carcinoma in situ or G1-G2 carcinoma. 88 patients presented with a single tumour, of which 14 (16%) had abnormal biopsies compared to 13 (48%) of the 27 presenting with multiple tumours. The difference between the 2 groups was statistically significant (p < 0.01). The incidence of freedom from new tumours at 5 years was 68% in patients with normal biopsies compared to 33% in patients with abnormal biopsies (p = 0.002). In patients presenting with multiple tumours and in those with single tumours and abnormal biopsies, the incidence of freedom from new tumours was significantly lower than in those presenting with single tumours and normal mucosal biopsies (p = 0.002). The study shows that the exercise of performing random mucosal biopsies is particularly useful in patients presenting with single tumours, in order to identify those who are more likely to develop new tumours over the longer term. Such patients could be offered early prophylactic intravesical chemotherapy. The study did not substantiate tumour implantation as a factor for new tumour development in superficial bladder cancer.