RESUMO
PURPOSE: To compare the usefulness of the World Health Organization (WHO) 1973 classification with the WHO/International Society of Urological Pathology (ISUP) classification in pTa bladder tumors. MATERIALS AND METHODS: A retrospective analysis was performed on 132 patients (107 men and 25 women; mean age 69 years) with a initial diagnosis of pTa bladder carcinoma. Median follow-up were 67 months. On the WHO 1973 classification, histopathological evaluation of initial diagnostic specimens revealed 51 cases with grade1, 68 cases with grade 2, 13 cases with grade3. All histological slides were examined by one genitourinary pathologist blinded with respect to clinical outcome and were classified according to the WHO/ISUP classification. Disease progression was defined as up stage (> or = pT1). Actual probability of progression-free and recurrence-free survival rate were estimated using the Kaplan-Meier method. The Log rank test was used to determine statistical difference between actual curves. Univariate and multivariate analyses were done using Cox regression analysis. The independent variables were multiplicity, histopathological grade, and adjuvant intravesical therapy. The dependent variable was disease progression and recurrence. RESULTS: The tumors were reclassified as low grade carcinoma in 77 and high grade carcinoma in 55. During the follow-up, 68 patients experience recurrence, 14 patients experienced disease progression. On the WHO 1973 classification, the risk of recurrence was significantly lower in patients with grade 1 compared to those with grade3 (p = 0.007). On the WHO/ISUP classification, the risk of recurrence and disease progression were significantly lower in patients with low grade compared to those with high grade (p = 0.003, P = 0.01). After adjustment for tumor multiplicity and adjuvant therapy, the relative risks of recurrence and progression in the low grade carcinoma versus the high grade carcinoma was 2.0 (95% confidence intervals 1.26-3.31), 5.6 (95% confidence intervals 1.54-20.48). CONCLUSIONS: In pTa bladder carcinoma, the WHO/ISUP classification was more useful prognostic factor than the WHO 1973 classification.
