Upper urinary tract tumors after primary superficial bladder tumors: prognostic factors and risk groups.

PURPOSE: We evaluated the prognostic factors of primary superficial bladder cancer that may predict a metachronous upper urinary tract tumor. We also determined whether the incidence of upper urinary tract disease varies according to risk group based on primary superficial bladder tumor classification.
MATERIALS AND METHODS: We studied disease evolution in a cohort of 1,529 patients with a primary superficial bladder tumor. To determine the prognostic factors of upper urinary tract cancer we performed multivariate analysis using Cox regression. Independent variables were grade, T stage, multiplicity, tumor size, carcinoma in situ association, previous or synchronous upper urinary tract tumor and intravesical instillation. We also performed the chi-square test and Kaplan-Meier survival analysis to assess the variable incidence of upper urinary tract tumors according to primary superficial bladder tumor risk group classification.
RESULTS: The incidence of upper urinary tract cancer was 2.6%. The only factor prognostic for an upper urinary tract tumor was multiplicity (relative risk 2.7, 95% confidence interval [CI] 1.06 to 6.84). All patients with an upper urinary tract tumor had a previously recurrent primary superficial bladder tumor. In the low, intermediate and high risk groups the incidence of upper urinary tract cancer was 0.6% (relative risk 1), 1.8% (relative risk 3.1, 95% CI 0.4 to 23.9) and 4.1% (relative risk 8.3, 95% CI 1.1 to 61.6), respectively (chi-square and log rank tests p = 0.007 and p <0.05, respectively).
CONCLUSIONS: A higher risk of upper urinary tract cancer must be expected in cases of multiple primary superficial bladder tumors. This finding supports the multicentricity theory of transitional cell carcinoma. Primary superficial bladder tumor classification by risk group is also useful for predicting the various risks of metachronous upper urinary tract cancer.