Pelvic lymph node (LN) metastasis is a well-recognized route of prostate cancer spread. However, the relationship between topography and pathologic features of primary prostatic cancers and patterns of pelvic LN metastasis has not been well studied. We reviewed original slides of radical prostatectomies and pelvic LN dissections from 125 patients with LN metastasis and recorded total # of LN excised / laterality of positive LN, as well as localization, staging parameters, lymphovascular invasion and tumor volume of primary tumors.
LN Quantity and Distribution
14.6 (mean) and 13 (median) LN were resected. 76 (61%), 33 (26%) and 16 (13%) cases had 1, 2 and > 2 positive LN, while 58, 44 and 20 cases had LN metastasis on the right (R), left (L), and bilaterally.
86% (108/125) and 37% (46/125) demonstrated extraprostatic extension and seminal vesicle invasion, while 64% showed lymphovascular invasion. Mean and median total tumor volume was 6.39 and 3.92 cc, with ≥ 50% and ≥ 90% Gleason patterns 4/5 in 105 (84%) and 73 (58%) cases, respectively.
Correlation with Dominant Tumor Location
Dominant lesions on RP: 50 R lobe, 44 L lobe, 31 bilateral. 15/50 (30%) R lobe and 18/44 (41%) L lobe dominant tumors had LN metastasis on the contralateral side. Only 4% (5/125) of cases were associated with anterior dominant tumors. 30–40% of LN metastases occur contralateral to the dominant tumor. LN metastasis is overwhelmingly associated with high grade, high stage and large volume disease. LN positivity is rarely associated with anterior dominant tumors.