Characters of lymphatic metastasis and their significance in radical prostatectomy

Abstract

Objective To evaluate the features about metastasis of different pelvic lymph node groups and their significance in radical prostatectomy.Methods From January 2004 to January 2014,the data of 103 patients with prostate cancer,who accepted the radical prostatectomy and extended pelvic lymph node dissection (e-PLND),were analyzed,retrospectively.The mean age was 64.9 years old (range 49-77years) and the mean preoperative PSA level was 14.7 μg/L (range 3.7-52.0 μg/L).The Gleason scores ranged from 5 to 10 scores (mean 6.9 scores).Risk group assessment showed low risk in 44 cases,intermediate risk in 31 cases and high risk in 28 cases.The pelvic lymph nodes were divided into 9 regions and 5groups according to the common guideline,including the external iliac,internal iliac,obturator and common iliac lymph nodes bilaterally,and the presacral lymph nodes.The frequency and density of pelvic lymphatic nodes metastasis in these patients were compared.Results Complete pathological information was available for 103 patients.Totally,2 136 lymph nodes were dissected.The numbers of dissected lymphatic nodes in each patients ranged from 13 to 37 (mean 21).Among them,22 patients were found the evidence of lymphatic node metastasis,including 2％ (1/44) with low risk group,26％ (8/31) with intermediate risk group and 46％ (13/28) in high risk group (P＜0.05).The metastatic total rate and degree of dissected lymph nodes were 21％.The metastatic frequency of lymph node groups in these patients from higher to Lower were as follows:59％ (13/22) in internal iliac region,50％ (11/22) in obturator region,36％ (8/22)in external iliac region,14％ (3/22) in presacral region and 5％ (1/22) in common iliac region,with a statistically significant difference in those groups (P＜0.05).The metastatic density of the lymph node groups from higher to lower were demonstrated as follows:37％ (19/53) in obturator region,33％ (3/9) in presaoral region,28％ (21/74) in internal iliae region,25％ (8/32) in external iliac region and 20％ (1/5) in common iliac region,with no statistically significant difference in those groups (P＞0.05).Conclusions In radical prostatectomy for the treatment of prostate cancer,it is not necessary to perform e-PLND in the low-risk group.It is suggested that the regional lymph nodes with intermediate-and high-risk group should be resected necessarily.Our study also suggested that the regional lymph nodes,including obturator,internal iliac and external iliac nodes,should be resected completely,due to the high metastatic rate and density.The presacral region should be the key to be checked,while regular dissection in common iliac region is not necessary. Key words: Postate neoplasms ; Radical prostatectomy ; Lymphatic metastasis ; Lymph node excision