title: Combination of ex vivo sentinel lymph node mapping and methylene blue-assisted lymph node dissection in gastric cancer: a prospective and randomized study.
abstract: BACKGROUND
  Exact lymph node (LN) staging is crucial for prognosis estimation and treatment stratification in gastric cancer. Recently, a new concept for improving LN harvest and the accuracy of LN staging was introduced. It combines methylene blue-assisted lymph node dissection (MBLND) with a new ex vivo sentinel lymph node (evSLN) mapping technique. The purpose of this study was to investigate these techniques in a prospective and randomized manner.
  
  
  METHODS
  A total of 50 patients with proven or suspicious gastric cancer were enrolled. Twenty-five patients each were randomized to the conventional technique (Unstained) or MBLND (Methylene). In 46 cases, additional evSLN mapping with black ink as a marker dye was performed.
  
  
  RESULTS
  Methylene blue-assisted lymph node dissection was associated with a highly significantly improved LN harvest (36 ± 10 vs. 21 ± 10; P < 0.001). The biggest differences were seen in LNs ≤ 6 mm. In contrast to the conventional technique, neither partial gastrectomy nor preoperative chemotherapy influenced LN harvest in the methylene group. The evSLN detection rate, sensitivity, and accuracy were 87, 81, and 93%, respectively. Isolated tumor cells were detected after immunohistochemical staining in 3 of 17 cases (18%). The probability of carrying a metastasis was two times higher in evSLNs compared to non-evSLNs (44 vs. 23%; P < 0.001).
  
  
  CONCLUSIONS
  Methylene blue-assisted lymph node dissection is a highly effective method of improving the LN harvest in gastric cancer. Further application of evSLN mapping is feasible and has the potential to heighten the sensitivity of metastasis detection.
authors.affiliation: Institute of Pathology, Klinikum Augsburg, Augsburg, Germany. Bruno.Maerkl@klinikum-augsburg.de
authors.forename: Bruno
authors.initials: B
authors.lastname: Märkl
authors.forename: Alexandra I
authors.initials: AI
authors.lastname: Moldovan
authors.forename: Hendrik
authors.initials: H
authors.lastname: Jähnig
authors.forename: Claudio
authors.initials: C
authors.lastname: Cacchi
authors.forename: Hanno
authors.initials: H
authors.lastname: Spatz
authors.forename: Matthias
authors.initials: M
authors.lastname: Anthuber
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Oruzio
authors.forename: Hallie
authors.initials: H
authors.lastname: Kretsinger
authors.forename: Hans M
authors.initials: HM
authors.lastname: Arnholdt
mesh_terms: D004396:Coloring Agents / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007269:Injections, Intra-Arterial; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D021701:Sentinel Lymph Node Biopsy; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000601:surgery*
chemical_list: D004396:Coloring Agents; D008751:Methylene Blue