Impact of lymphovascular invasion on lymph node metastasis for patients undergoing radical prostatectomy with negative resection margin.

Background: The association between lymphovascular invasion and lymphatic or hematogenous metastasis has been suspected, with conflicting evidence. We have investigated the association between the risk of biochemical recurrence and lymphovascular invasion in resection margin negative patients, as well as its association with lymph node metastasis.

Methods: One thousand six hundred thirty four patients who underwent radical prostatectomy from 2005 to 2014 were selected. Patients with bone or distant organ metastasis at the time of operation were excluded. Survival analysis was performed to assess biochemical recurrence, metastasis and mortality risks by Kaplan-Meier analysis and multivariate Cox proportional hazard regression. Odds of lymph node metastasis were evaluated by Logistic regression.

Results: LVI was detected in 118 (7.4%) patients. The median follow-up duration was 33.1 months. In the Kaplan-Meier analysis, lymphovascular invasion was associated with significantly increased 5-year and 10-year BCR rate (60.2% vs. 39.1%, 60.2% vs. 40.1%, respectively; p < 0.001), 10-year bone metastasis rate and cancer specific mortality (16.9% vs. 5.1%, p = 0.001; 6.8% vs. 2.7%, p = 0.034, respectively) compared to patients without LVI. When stratified by T stage and resection margin status, lymphovascular invasion resulted in significantly increased 10-year biochemical recurrence rate in T3 patients both with and without positive surgical margin (p = 0.008, 0.005, respectively). In the multivariate Cox regression model lymphovascular invasion resulted in 1.4-fold BCR risk and 1.7-fold metastasis risk increase (95% CI 1.045-1.749, 1.024-2.950; p = 0.022, 0.040, respectively). Lymphovascular invasion was revealed to be strongly associated with lymph node metastasis in the multivariate Logistic regression (OR 4.317, 95% CI 2.092-8.910, p < 0.001).

Conclusion: Lymphovascular invasion increases the risk of recurrence in T3 patients regardless of margin status, by accelerating lymph node metastasis and distant organ metastasis.