Peritumoral lymphatic invasion is associated with regional lymph node metastases in prostate adenocarcinoma

Lymphangiogenesis, detected by antibodies specific for lymphatic endothelial cells, has been associated with regional lymph node metastases and poor prognosis in carcinomas of head and neck, breast and uterine cervix, but remains largely uninvestigated in prostate adenocarcinoma. We evaluated the lymphatic vessel density and lymphatic vessel invasion by prostate cancer cells in the intratumoral, peritumoral and normal prostate tissue compartments in cancer-bearing prostate glands and correlated them with lymph node metastases, Gleason score and other pathological parameters. Lymphatic vessels were detected by immunohistochemical stain using an antibody specific for the lymphatic endothelial cells (clone D2-40) on 33 radical prostatectomies. In all, 26 patients had lymph node dissection, and 14 of them had lymph node metastasis. The lymphatic vessel density and lymphatic vessel invasion were then recorded for each of the three compartments microscopically. Lymphatic vessel density in the intratumoral, peritumoral and normal prostate compartments was 0.91 ± 0.80, 1.54 ± 0.68 and 1.58 ± 0.96/mm², respectively. The intratumoral lymphatic vessel density was significantly lower than that of the peritumoral and normal prostate compartments, and the latter two were not significantly different. The lymphatic vessel density of the three compartments was not significantly different between cases with and without lymph node metastasis. The peritumoral lymphatic vessel density correlated inversely with the Gleason score. Lymphatic vessel invasion was present in significantly higher percentage of cases with lymph node metastasis (9/14, 62.3%), as compared to those without lymph node metastasis (1/12, 8.3%, P<0.01). The peritumoral lymphatic vessel invasion had a better correlation with the presence of lymph node metastases than intratumoral lymphatic vessel invasion. There is no evidence of lymphangiogenesis in prostate adenocarcinoma. Peritumoral lymphatic vessel invasion correlates with regional lymph node metastases, suggesting that the peritumoral lymphatic vessels are functionally important and identification of lymphatic vessel invasion in this compartment implies a high probability of regional lymph node metastases.