The prognostic value of basement membrane morphology, tumour histology and morphometry in superficial bladder cancer

Abstract

This analysis evaluated the prognostic importance of clinical, histological (WHO grade, papillary status, tumour-infiltrating lymphocytes) and morphometric factors (mitotic index, mean nuclear area, SD of nuclear area) in a cohort of 132 patients with a Ta-T1 transitional cell bladder cancer followed-up for over 8 years. Special attention was given on the state of the subepithelial basement membrane (BM) and subepithelial vascular density as demonstrated by type IV collagen immunostaining. Defects in the BM and dense vascular network were related to nodular growth pattern, high histological grade, rapid cancer cell proliferation and a dense inflammatory cell infiltrate (tumour-infiltrating lymphocytes, TIL) in tumour stroma. The most important predictor of progression was the mitotic index (P < 0.0001) followed by vascular density (P = 0.0054), the state of the BM (P = 0.0056), density of TIL (P = 0.0193), WHO grade (P = 0.0356) and papillary status (P = 0.0448). In univariate survival analysis the mitotic index (P < 0.0001), the state of the BM (P < 0.0001), subepithelial vascular density (P = 0.0013) and WHO grade (P = 0.01) predicted survival. In a multivariate analysis the mitotic index (P < 0.0001) and the state of the BM (P = 0.008) were independent predictors. The results show that the evaluation of the mitotic rate and investigation of the continuity of the BM should be done whenever the prognosis of Ta-T1 tumours of the bladder is assessed.