Detecting lymph nodes metastasis in prostate cancer through extended vs. standard laparoscopic pelvic lymphadenectomy

Pelvic lymphadenectomy is the best method for staging localized prostate cancer. There is no consensus about how the pelvic lymphadenectomy should be performed for patients with cT2, Gleason score 7 or higher, PSA higher than 10 ng/mL. Scintigraphic studies of prostate lymph drainage show that many lymph nodes are not dissected according to the current recommendation of lymphadenectomy which could explain the high rate of cancer recurrence. The objectives of this work are an analysis of the local lymph node metastasis according to the preoperative data (digital examination, PSA and Gleason score) and a comparison between laparoscopic extended and limited pelvic lymphadenectomy, for staging, their technique and complications.

Two groups were created for analysis. The indications for laparoscopic pelvic lymph-adenectomy are the following: preoperative PSA 10 ng/mL or higher, Gleason score 7 or higher and/or digital examination cT2. Patients with suspected distant metastasis were excluded. The first group is composed of the patients who under-went a limited laparoscopic pelvic lymphadenectomy (LLPL) between January 1995 and December 2002. The medical data were analyzed retrospectively. The second group was created with patients who received extended laparoscopic pelvic lymphadenectomy (ELPL). These data were consecutively collected between November 2006 and October 2007. LLPL was the extraction of the external iliac and obturator lymph nodes. ELPL included, additionally, dissection of the internal iliac lymph nodes as well as tissue medial to the genitofemoral nerve. Histopathological findings were compared with serum PSA, histopathological stage and preoperative biopsy. Complications, operating time, and number of extracted lymph nodes were also compared.

There were no significant differences in age, serum PSA or mean biopsy Gleason between two groups. The first group (LPLL) is composed of 381 patients and the second (ELPL), 163. The mean operating time was 72.5 minutes for LLPL and 84.3 for ELPL. The mean number of lymph nodes extracted was 13.8 (LLPL) and 31.1 (ELPL). Metastases were detected in 18.8% (LLPL) and 24.7% (ELPL). In 37.5% of cases, the metastasis occurred in lymph nodes outside from those dissected by LPLL. The rates of complications and conversion rate were not significantly different for the two groups.

For patients with clinically localized prostate cancer, ELPL is associated with a higher rate of detection of lymph node metastasis outside of the field dissected in the LPLL. Pelvic lymphadenectomy, especially extraction of the lymph nodes of the internal iliac is important in patients with preoperative Gleason score 7 or greater and/or serum PSA greater than 10 ng/mL. Laparoscopic lymphadenectomy does not augment the rate of complications and is an excellent technique in prostate cancer staging.