SIGNIFICANCE OF TUMOR ANGIOGENESIS IN CLINICALLY LOCALIZED PROSTATE CARCINOMA TREATED WITH EXTERNAL-BEAM RADIOTHERAPY

Objectives. To determine the prognostic significance of microvessel de nsity (a measure of tumor angiogenesis) in comparison with other progn ostic factors for patients with clinically localized prostatic carcino ma treated with external beam radiotherapy. Methods. Microvessel densi ty was quantified within the initial invasive carcinoma from the diagn ostic transurethral resection specimen of 25 patients with a mean foll ow-up of 44 months. Microvessels were identified by immunohistochemica l staining of endothelial cells for factor VIII-related antigen in for malin-fixed, paraffin-embedded tissue. Microvessels were counted in a x200 field (0.754 mm(2)) in the area of maximal angiogenesis. Results. Microvessel density correlated with several pretreatment prognostic f actors, including prostate-specific antigen (PSA) (p < 0.0001), tumor grade (p = 0.006), and ploidy (p = 0.016). The degree of tumor angioge nesis also correlated with outcome following external beam radiotherap y. The mean microvessel count in the nine tumors from patients who fai led radiotherapy tie, 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 nand evidence of failure (p < 0.0001). Increased micr ovessel density was also associated with a significantly worse actuari al outcome at 4 years using either biochemical relapse (rising PSA) or a composite endpoint of rising PSA or clinical relapse (p = 0.0005). Conclusions. The intratumoral quantification of tumor angiogenesis may prove valuable as a prognostic indicator in patients with clinically localized prostate cancer treated with radiotherapy.