The predictive value of muscularis mucosae invasion and p53 over expression on progression of stage T1 bladder carcinoma

PURPOSE: We determine the significance of muscularis mucosae invasion and nuclear p53 over expression on the progression of stage T1 transitional cell bladder cancer. MATERIALS AND METHODS: The pathological findings in 149 cases of T1 tumors diagnosed between 1973 and 1996 were reviewed. Diagnosis was stage T1 in 94 tumors in which the muscular layer was clearly identifiable and disease-free. Mean followup was 64.9 months (range 5 to 288). T1 bladder cancers were subclassified into 2 groups, with (T1b) or without (T1a) muscularis mucosae invasion. The p53 nuclear antibody immunoreactivity was determined with antibody D07 and a cutoff point at 15%. RESULTS: T1 subclassification was possible in all 94 patients. Of all tumors 37.2% expressed p53 nuclear over expression. Univariate statistical analysis showed that p53 expression (p <0.05) and tumor invasion depth (p <0.001) significantly correlated with progression. However, on multivariate analysis only invasion depth (p <0.0001) and associated carcinoma in situ (p <0.03) remained independently significant as predictors of progression. CONCLUSIONS: In our study the depth of tumor invasion was a significant independent predictor of progression in patients with T1 bladder cancer. This result suggests that the depth of invasion in stage T1 should be included in the histopathological report.