Objective: To determine if the morphologic subgrouping of grade I bladder tumors between papillary neoplasm of low malignant potential and low grade papillary carcinoma is of clinical and survival value.
Material and methods: All 257 consecutive patients diagnosed of superficial bladder cancer between 1990 and 1995 in HU Reina Sofia of Cordoba were reviewed and further reclassified according to WHO/ISUP consensus classification of urothelial neoplasms of the bladder. Of the tumors 12 were urothelial papilloma, 51 were papillary neoplasm of low malignant potential, 43 were low grade papillary carcinoma Ta, 65 were low grade papillary carcinoma T1 and 37 were high grade papillary carcinoma. Eleven patients were reevaluated as T2 tumors and 38 (14.8%) were lost of control. All patients were reviewed with a follow-up at least of 5 years. We compare the results between groups with Fisher test and the risk factors for recurrence and progression are analyzed by multivariate analysis (Odds ratio). The survival function was calculated using Kaplan-Meier estimates and compared with the log-rank test.
Results: There are no differences between groups respect the age or sex distribution. The differences in the multiplicity are not significant and only the mean size is higher in papillary low grade carcinoma. About the risk factors for recurrence and progression of the disease, only is significative the tumor size. Rarely, the use of chemotherapy seems to play a role in the recurrence. There are no differences in recurrence and progression between the groups, although the percentages are always higher in the papillary low grade carcinoma group.
Conclusions: There are enough clinical differences between the two groups and we consider them as distinct pathologic entities. Only the higher tumoral size is prognostic factor in each group. We think that the use of chemotherapy must be avoided in this low grade bladder tumors.