title: [Injection of methylene blue into inferior mesenteric artery improves lymph node harvest in rectal cancer after neoadjuvant chemotherapy].
abstract: OBJECTIVE
  To confirm the feasibility of improving lymph node harvest by injecting methylene blue into inferior mesenteric artery in rectal cancer after neoadjuvant therapy.
  
  
  METHODS
  Forty two ex vivo specimens were collected from rectal cancer patients with neoadjuvant therapy and radical operation at our hospital. Traditional method with palpation and injection of methylene blue into inferior mesenteric artery were employed. The data of lymph node harvest were analyzed by paired t and chi-square tests.
  
  
  RESULTS
  The average number of detected lymph node in traditional method and methylene blue groups were 6.1 ± 4.3 and 15.2 ± 6.4 respectively (P<0.001). The proportions of lymph nodes <5 mm were 14.1% and 46.7% in traditional method and methylene blue groups respectively (P<0.001). And the injection of methylene blue added 13 extra metastatic lymph nodes and caused a shift to node-positive stage (P=0.89).
  
  
  CONCLUSIONS
  Neoadjuvant therapy decrease lymph node retrieval in rectal cancer. Injecting methylene blue into inferior mesenteric artery improves lymph node harvest especially for small nodes and helps to acquire more metastatic nodes for accurate pathological staging.
authors.affiliation: Department of Gastrointestinal Surgery, Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China.
authors.forename: Jianpei
authors.initials: J
authors.lastname: Liu
authors.forename: Pinjie
authors.initials: P
authors.lastname: Huang
authors.forename: Jianglong
authors.initials: J
authors.lastname: Huang
authors.forename: Tufeng
authors.initials: T
authors.lastname: Chen
authors.affiliation: Email: drwhb@21cn.com.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Wei
mesh_terms: D006801:Humans; D007267:Injections; D008197:Lymph Node Excision; D008198:Lymph Nodes; D017537:Mesenteric Artery, Inferior; D008751:Methylene Blue; D020360:Neoadjuvant Therapy; D012004:Rectal Neoplasms
chemical_list: D008751:Methylene Blue