Prediction of Patient Outcome in Pathologic Stage T2 Adenocarcinoma of the Prostate: Lack of Significance for Microvessel Density Analysis

Abstract

Objectives. Some patients with palpable intermediate- and high-grade, margin-free, organ-confined prostate cancer experience recurrence following prostatectomy. We studied the ability of microvessel density and other factors to predict recurrence in such patients with pathologic Stage T2 cancer. Methods. Between 1987 and 1991, 307 patients underwent radical prostatectomy for Gleason score 6 to 9, margin-free, organ-confined prostate cancer at Mayo Clinic, Rochester, Minnesota. Specimens from 147 patients with sufficient cancer tissue for immunohistochemical staining with Factor VIII-related antigen were studied by computer-assisted digital image analysis for optimized microvessel density (OMVD). The correlation of deoxyribonucleic acid (DNA) ploidy, Gleason score, OMVD, unilateral disease, bilateral disease, and preoperative prostate-specific antigen (PSA) to cancer recurrence was assessed using the Cox model. Biochemical recurrence was defined as postoperative increase in PSA of greater than 0.2 ng/mL, and clinical recurrence was defined as positive biopsy or metastasis on bone scan. Results. Mean follow-up for all patients was 6.1 years, with 12 deaths (1 due to prostate cancer) and 58 cases of clinical and/or biochemical recurrence. OMVD was not significantly associated with DNA ploidy, Gleason grade, unilateral disease, bilateral disease, or preoperative PSA. Preoperative PSA was the strongest predictor of clinical and/or biochemical recurrence in both univariate and multivariate analysis. OMVD was not a significant univariate or multivariate predictor of clinical and/or biochemical recurrence. The estimated relative risk of clinical and biochemical recurrence associated with a change in OMVD from the 25th percentile (OMVD 45) to the 75th percentile (OMVD 84) was 1.08 (95% confidence interval 0.79 to 1.47). Conclusions. Preoperative PSA was the strongest predictor of clinical and/or biochemical recurrence of prostate cancer in this group of patients. Optimized microvessel density did not predict outcome in a select cohort of patients with palpable intermediate- and high-grade, margin-free, organ-confined prostate cancer (TNM stage T2N0M0).