Extended pelvic lymphadenectomy in patients undergoing radical prostatectomy: High incidence of lymph node metastasis

Purpose: Lymphadenectomy for prostate cancer is limited to obturator and external iliac lymph nodes, although the internal lymph nodes represent the primary landing zone of lymphatic drainage. We performed anatomically adequate extended pelvic lymphadenectomy to assess the incidence of lymph node metastasis in cases of clinically localized prostate cancer. Materials and Methods: A total of 103 consecutive patients underwent extended pelvic lymphadenectomy at radical retropubic prostatectomy comprising 9 selective fields, namely the external iliac, internal iliac, obturator and common iliac lymph nodes bilaterally, and the presacral lymph nodes. Histopathological findings were compared with serum prostate specific antigen (PSA), histopathological stage, preoperative biopsy and postoperative prostatectomy Gleason score. Extended pelvic lymphadenectomy was compared with radical retropubic prostatectomy and standard lymphadenectomy in 100 consecutive patients in terms of complications, the number of lymph nodes dissected and operative time. Results: There were no significant differences in age, preoperative PSA or mean biopsy Gleason score in patients who underwent extended pelvic and standard lymphadenectomy. Metastases were diagnosed in 27 of the 103 patients (26.2%) who underwent the extended procedure. A mean of 28 lymph nodes (range 21 to 42) were dissected. Metastases were identified in the internal iliac and presacral regions despite negative obturator lymph nodes. Of the 27 patients 1 to 3 lymph nodes involved with metastasis were detected in 15, 9 and 1, respectively. In 26 of the 27 patients (95.8%) with lymph node metastasis PSA was greater than 10.5 ng./ml. and preoperative biopsy Gleason sum was 7 or greater. A low risk of 2% for lymph node disease was noted in patients with serum PSA less than 10.5 ng./ml. and biopsy Gleason sum less than 7. There were no significant differences in regard to intraoperative and postoperative complications, lymphocele formation or blood loss in the 2 groups. Conclusions: Extended pelvic lymphadenectomy is associated with a high rate of lymph node metastasis outside of the fields of standard lymphadenectomy in cases of clinically localized prostate cancer. Lymphadenectomy including the internal iliac lymph nodes should be performed in all patients with prostate cancer who are at high risk for lymph node involvement, as indicated by PSA greater than 10.5 ng./ml. and biopsy Gleason sum 7 or greater. In the low risk group pelvic lymphadenectomy can be omitted.