Prognostic relevance of micro-vessel density in cancer of the urinary bladder.

Angiogenesis is an important factor in tumour growth and metastasis. Degree of angiogenesis (microvascular density-MVD) has been found to correlate with tumour progression and disease outcome in a number of different malignancies. We studied 88 patients undergoing cystectomy for transitional cell bladder cancer to determine if angiogenesis was associated with cancer specific survival. Microvessels were identified by immunostaining of endothelial cells for CD31. Active areas of angiogenesis ("hot spots") were selected using low magnification. The vessel count was performed using a Chalkley point graticule. The mean of 3 counts was used for statistical analysis. The median count was 3.4. Univariate analysis revealed that higher MVD was associated with worsening prognosis (p = 0.02). When adjusted for clinical stage MVD continued to predict worsening prognosis (p = 0.02). MVD was not affected by age or sex or by previous radiotherapy. MVD was associated with the risk of patients dying following pelvic recurrence (p = 0.03) and MVD was significantly higher in patients with lymph node metastasis at surgery. In conclusion, microvessel density proved to be an independent prognostic marker in transitional cell carcinoma of bladder.