Role of microvessel density in predicting recurrence in pathologic Stage T3 prostatic adenocarcinoma

Extraprostatic extension of prostatic adenocarcinoma (pathologic Stage T3) increases the risk of recurrence after radical prostatectomy compared with organ-confined prostate cancer. Use of microvessel density in predicting cancer recurrence in Stage pT3 cancer is poorly understood. We evaluated known predictors of recurrence, including Gleason grade, preoperative serum prostate-specific antigen (PSA), DNA ploidy, seminal vesicle involvement, and surgical margin status in comparison with optimized microvessel density (OMVD) and area-weighted microvessel density (AWMVD) in patients with Stage pT3 prostate cancer.

Between 1987 and 1989, 290 previously untreated patients underwent radical prostatectomy and were found to have pathologic Stage T3 adenocarcinoma. No patient received adjuvant therapy. Embedded prostatectomy specimens from 211 patients with sufficient tissue for immunohistochemical staining with factor VIII-related antigen were studied by computer-assisted digital image analysis for OMVD and AWMVD. The correlation of Gleason grade, preoperative PSA, DNA ploidy, seminal vesicle involvement, surgical margin positivity, OMVD, and AWMVD with clinical or biochemical failure was assessed using the Cox proportional hazards model. Biochemical failure was defined as a postoperative increase in PSA greater than 0.2 ng/mL, and clinical failure was defined as a positive biopsy or metastasis on bone scan.

The mean follow-up +/- SD for all patients was 7.1 +/- 1.8 years, with 43 deaths (9 due to prostate cancer) and 124 cases of clinical and/or biochemical recurrence. The mean OMVD was 65.0 +/- 17.3, and the mean AWMVD was 8.2 +/- 5.3. OMVD and AWMVD were not predictors of cancer recurrence or significantly associated with DNA ploidy or preoperative PSA. AWMVD was associated with Gleason grade (P = 0.003). The estimated relative risk (adjusted for other cancer variables) of clinical and biochemical recurrence associated with a change in OMVD from the 25th percentile (53.5) to the 75th percentile (75.4) was 1.14 (95% confidence interval 0.92 to 1.42). The estimated relative risk (adjusted) of clinical and biochemical recurrence associated with a change in AWMVD from the 25th percentile (4.8) to the 75th percentile (10.4) was 1.17 (95% confidence interval 0.97 to 1.42). Gleason grade, preoperative PSA, DNA ploidy, and seminal vesicle involvement were predictors of clinical and/or biochemical recurrence in univariate and multivariate analyses.

Microvessel density, assessed by OMVD and AWMVD, did not predict recurrence in patients with pathologic Stage T3 adenocarcinoma of the prostate (TNM Stage T3N0M0). DNA ploidy, Gleason grade, preoperative PSA, and seminal vesicle involvement remained the best predictors of clinical and/or biochemical recurrence in this group of patients.