Long-term outcome of bladder papillary urothelial neoplasms of low malignant potential

Objective To evaluate the long-term outcome of bladder papillary urothelial neoplasms of low malignant potential (PUNLMP). Patients and Methods Of 475 consecutive patients with newly diagnosed bladder tumours between 1976 and 1993, 330 (69%) had superficial (Ta and T1) tumours and 53 (11%) were diagnosed as having PUNLMP. Fifty patients ( mean age at presentation 57.2 years, range 26-83; male-to-female ratio 6:1) who were followed for >5 years or until they died, were included in the present study. All histological slides were reviewed, and fulfilled the diagnostic criteria of the 1998 World Health Organization/International Society of Urological Pathology classification system. Results The mean (median, range) follow-up was 11.7 (10.8, 1.3-24.4) years. During the follow-up, 30 patients (60%) had local recurrences. The 2, 5 and 10-year recurrence-free rates were 66%, 51% and 36%, respectively. No patients developed high-grade or muscle-invasive (greater than or equal toT2) carcinomas, or upper urinary tract tumours, or died from the disease. At the last follow-up, 34 patients (68%) had been disease-free for >5 years. Conclusions Despite a high recurrence rate, PUNLMP carries a very low malignant potential. We agree with the use of the term 'papillary urothelial neoplasms of low malignant potential' instead of 'superficial bladder carcinoma (cancer)' for these tumours.