UROLOGICAL ONCOLOGY

The template of the primary lymphatic landing sites of the prostate should be revisited: results of a multimodality mapping study
Mattei A, Fuechsel FG, Bhatta Dhar N, Warncke SH, Thalmann GN, Krause T, Studer UE
Department of Urology, University Hospital of Bern, Switzerland
Eur Urol. 2008; 53: 118-25

• Objectives: To map the primary prostatic lymphatic landing sites using a multimodality technique.
• Methods: Thirty-four patients with organ-confined prostate cancer (cT1-cT2; cN0) underwent single-photon emission computed tomography fused with data from computed tomography (SPECT/CT) (n = 33) or magnetic resonance imaging (SPECT/MRI) (n = 1) 1h after ultrasound-guided intraprostatic injection of technecium (Tc-99m) nanocolloid. The presence of lymph nodes (LNs) containing Tc-99m was confirmed intraoperatively with a gamma probe. A backup extended pelvic lymphadenectomy (PLND) was performed to preclude missed primary lymphatic landing sites. The SPECT/CT/MRI data sets were used to generate a three-dimensional projection of each LN site.
• Results: A total of 317 LNs (median, 10 per patient; range, 3-19) were detected by SPECT/CT/MRI, 314 of which were confirmed by gamma probe. With an “extended” PLND, two thirds of all primary prostatic lymphatic landing sites are resected compared with only one third with a “limited” PLND.
• Conclusions: The multimodality technique presented here enables precise mapping of the primary prostatic lymphatic landing sites. PLND for prostate cancer should include not only the external and obturator regions as well as the portions medial and lateral to the internal iliac vessels, but also the common iliac LNs at least up to the ureteric crossing, thus removing approximately 75% of all nodes potentially harbouring metastasis.
  
  
• Editorial Comment
  This report from Berne, Switzerland focuses on the extend of retroperitoneal lymph node dissection in prostate cancer. The authors used Spect/CT and MRI data to localize the lymph nodes in prostate cancer and tried to remove these during radical prostatectomy. They found primary landing site lymph nodes up to the mesenteric vein and para-aorta. The authors conclude that upon classical lymph-node dissection (LND) only 38% of the relevant lymph nodes are removed. On the other hand, pararectal, pre-sacral and para-aortal LND would add to morbidity and would compromise the results of nerve-sparing RPE. Therefore, an extended LND is seen as a compromise in patients with risk of nodal disease, where the template of classical extended LND is encompassed by a template including the common iliac arteries up to where the ureters cross. By this extended template up to 75% of the relevant lymph nodes would be removed.

Dr. Andreas Bohle
Professor of Urology
HELIOS Agnes Karll Hospital
Bad Schwartau, Germany
E-mail: boehle@urologie-bad-schwartau.de