Lymphovascular invasion in prostate cancer: prognostic significance in patients treated with radiotherapy after radical prostatectomy.

Abstract

Lymphovascular invasion (LVI) is found in approximately 5% to 53% of specimens after radical prostatectomy (RP). Although LVI is associated with higher rates of recurrence after RP, its prognostic significance after postprostatectomy radiotherapy (P-XRT) is unclear. The medical records of men who received P-XRT from 1991 to 2001 at 2 institutions were reviewed for the presence of LVI in RP specimens. Multiple patient variables were evaluated for their association with LVI using Fisher exact tests and Wilcoxon rank-sum tests. The time to biochemical recurrence (BCR) and the time to distant metastases (DM) after RP were analyzed using Kaplan-Meier estimations, log-rank tests, and Cox regression analyses. Eighteen of 160 patients (11%) who received P-XRT had LVI in their RP specimen. High Gleason score and seminal vesicle invasion were associated significantly with LVI. After a median follow-up of 8.3 years after RP, 16 patients with LVI had BCR after P-XRT, 9 of whom developed DM. The median time to BCR in patients with LVI was 2.6 years (95% confidence interval [95% CI], 1.8-5.4) compared with 7.8 years (95% CI, 6.8-10.3) in patients without LVI (P < .001). Multivariate analysis revealed an adjusted relative risk for LVI of 5.5 (P < .001). Other significant factors were Gleason score, undetectable post-RP serum prostate-specific antigen (PSA) levels, preradiotherapy serum PSA levels, and the interval from RP to P-XRT. LVI was the only significant factor associated with an increased risk of DM in univariate analysis (hazard ratio, 7.4; P < .001). LVI was useful as a pathologic marker for reduced efficacy of P-XRT after RP in terms of increased risk of BCR and DM. Future studies will be needed to validate these findings.