Superficial bladder tumours: analysis of prognostic factors and construction of a predictive index.

OBJECTIVES

To assess the prognostic factors that could be used to predict tumour recurrence and progression, and to construct and validate a predictive index.

PATIENTS AND METHODS

Between June 1991 and December 2000, 533 patients (418 men and 115 women; mean age 55.4 years) underwent complete transurethral resection of histologically confirmed pTa and pT1 transitional cell carcinoma of the bladder, after which 377 (test series) were randomized into two subsequent studies, of six groups, to receive adjuvant intravesical sequential bacillus Calmette-Guérin (BCG) and epirubicin, BCG alone, epirubicin (50 or 80 mg), adriamycin 50 mg or no adjuvant therapy. Factors potentially affecting tumour recurrence or progression were assessed using univariate and multivariate analysis, i.e. tumour stage, histological grade, DNA ploidy, history of recurrence, multiplicity, size, tumour configuration, associated carcinoma in situ, recurrence at the first 3-month check cystoscopy and the use of adjuvant therapy. The regression coefficients determined by Cox regression analysis were used to construct a predictive index (PI). The algebraic sum of the regression coefficients of the factors with independent and significant association with disease-free survival for each case represented a proportional hazard score (PHS). The PI was validated in another series of 156 patients (validation series) in whom the same regression coefficients for the same significant factors as the test series were used to categorize it into three risk groups. Kaplan-Meier survival curves were plotted to compare the different risk categories in both test and validation series.

RESULTS

The mean (sd, range) follow-up in the test and validation series were 58 (19, 5-96) and 28.3 (14.9, 2-94) months, respectively. In the test series, tumour stage, DNA ploidy, multiplicity, history of recurrence, tumour configuration, cystoscopy result and the type of adjuvant therapy had independent significance for recurrence on multivariate analysis. For progression, the cystoscopy result, DNA ploidy and grade were the only independent and significant predictors. The ranges of PHS for the factors affecting recurrence-free and progression-free survival were 0.0-7.14 and 0.0-5.84, respectively, which were divided equally into three risk categories with significant differences on Kaplan-Meier curves and a log-rank test (P < 0.001). The three categories in the validation series were significantly different from each other and each was comparable with that in the test series.

CONCLUSIONS

Tumour stage, DNA ploidy, multiplicity, history of recurrence, tumour configuration and type of adjuvant therapy affected independently the rate of recurrence after resecting superficial bladder tumour. Recurrence at the 3-month cystoscopy, histological grade and DNA ploidy were the only predictors of progression to muscle-invasion. The PI dividing the patients into three risk groups with different treatment and follow-up strategies for recurrence and progression was reproducible in a validation series.