Tumor size predicts the survival of patients with pathologic stage T2 bladder carcinoma - A critical evaluation of the depth of muscle invasion

BACKGROUND. Accurate examination of radical cystectomy specimens is critica l for stratifying patients into prognostically important groups and determi ning the need for adjuvant treatment. Evidence has accumulated that cancers invading the superficial muscle wall (T2a) behave similarly to those invad ing the deep muscle wall (T2b). Quantitative analysis of the depth of invas ion in relation to patient outcome is needed. METHODS, The authors systematically evaluated the depth of invasion by micr ometer measurement and its relation to the survival of 64 patients with bla dder carcinoma pathologic classification as pT2 who had long term follow-up after radical cystectomy. Numerous clinical and pathologic variables were analyzed with univariate and multivariate Cox proportional hazards models. The mean age of patients was 64 years, and their mean follow-up was 8.3 yea rs. RESULTS. There was no significant difference in clinical outcome between pa tients with T2a carcinoma and those with T2b. Lymph node metastasis and tum or size were each significantly associated with distant metastasis free and cancer specific survival. Ten-year distant metastasis free and cancer spec ific survival were 100% and 94%, respectively, for patients with tumors <3 cm (P = 0.006) and 68% and 73%, respectively, for patients with tumors grea ter than or equal to 3 cm (P = 0.005). After adjustment for lymph node stat us, tumor size maintained significance in predicting distant metastasis fre e survival (risk ratio, 1.5; 95% confidence interval, 1.1-2.0; P = 0.009) a nd cancer specific survival (risk ratio, 1.5; 95% confidence interval, 1.1- 1.9; P = 0.01). Age was associated with recurrence free survival and all-ca use survival. None of the other variables, including gender, vascular invas ion, presence of carcinoma in situ, pathologic classification (T2a vs. T2b) , depth of invasion, depth of muscle invasion, ratio of depth of invasion t o bladder wall thickness, and percentage of muscle wall invasion, were sign ificantly associated with patient outcome. CONCLUSIONS, The findings of this study indicate that the subclassification of T2 bladder carcinoma by depth of muscle invasion is of no prognostic va lue; conversely, tumor size, an easily measured factor, is predictive of di stant metastasis free and cancer specific survival. Cancer 1999;85:2638-47, (C) 1999 American Cancer Society.