[Clinical significance of random mucosal biopsies in patients with bladder cancer: analysis of 117 cases].

The results of multiple random biopsies from apparently non-tumor bearing mucosa were analyzed in 117 cases with bladder cancer. Of the 687 evaluable specimens, 26.5% showed abnormalities including hyperplasia (12.4%), atypical hyperplasia (5.8%), flat carcinoma in situ (6.0%) and even occult carcinoma (2.3%). The frequency of mucosal lesions increased with advancing histologic grade of visible tumors. The frequency of occult cancerous or precancerous lesions in cases with visible tumors was significantly higher than that of cases with invisible tumors. Undoubtedly the existing of occult cancerous or precancerous lesions is one of the important factors of high recurrence rate after local resection of the bladder tumors. Patients with occult cancerous or precancerous lesions should be given intensive follow-up and intravesical prophylactic therapy.