Objectives: To determine the prognostic significance of microvessel density (a measure of tumor angiogenesis) in comparison with other prognostic factors for patients with clinically localized prostatic carcinoma treated with external beam radiotherapy.
Methods: Microvessel density was quantified within the initial invasive carcinoma from the diagnostic transurethral resection specimen of 25 patients with a mean follow-up of 44 months. Microvessels were identified by immunohistochemical staining of endothelial cells for factor VIII-related antigen in formalin-fixed, paraffin-embedded tissue. Microvessels were counted in a x200 field (0.754 mm2) in the area of maximal angiogenesis.
Results: Microvessel density correlated with several pretreatment prognostic factors, including prostate-specific antigen (PSA) (p < 0.0001), tumor grade (p = 0.006), and ploidy (p = 0.016). The degree of tumor angiogenesis also correlated with outcome following external beam radiotherapy. The mean microvessel count in the nine tumors from patients who failed radiotherapy (ie, had rising PSA and/or clinical relapse) was 97.0 +/- 33.6 (+/- SD) per x200 field compared with 46.1 +/- 17.1 for the 16 patients with no evidence of failure (p < 0.0001). Increased microvessel density was also associated with a significantly worse actuarial outcome at 4 years using either biochemical relapse (rising PSA) or a composite endpoint of rising PSA or clinical relapse (p = 0.0003).
Conclusions: The intratumoral quantification of tumor angiogenesis may prove valuable as a prognostic indicator in patients with clinically localized prostate cancer treated with radiotherapy.