title: Helium pneumoperitoneum reduces tumor recurrence after curative laparoscopic liver resection in rats in a tumor-bearing small animal model.
abstract: BACKGROUND
  After exposure of neoplastic tissue to helium, a significant reduction of tumor growth has been detected in experimental studies, both in vitro and in vivo. This tumor-suppressive effect of helium is controversly discussed in the literature. It was therefore the aim of this study to investigate the influence of pneumoperitoneum with CO2, room air, or helium in a tumor-bearing small animal model comparing laparoscopic partial hepatic resection for hepatocellular carcinoma with conventional open partial hepatectomy.
  
  
  METHODS
  One-hundred forty-eight male American Cancer Institute rats underwent partial hepatectomy for curative resection of previously induced hepatocellular carcinoma (Morris hepatoma 3924A). Resection was performed either in open laparotomy (n = 30) or laparoscopically under the employment of CO2 (n = 30), room air (n = 30), or helium (n = 30) for the pneumoperitoneum. Twenty-eight animals served as controls receiving anesthesia but no tumor resection. All animals were sacrificed on postoperative days 21, 35, or 56 for autopsy and evaluation of possible tumor recurrence and metastasis.
  
  
  RESULTS
  Significant reduction of postoperative tumor recurrence and metastasis was observed in the group of animals receiving laparoscopic tumor resection under helium insufflation compared to open surgery or laparoscopic resection with air pneumoperitoneum.
  
  
  CONCLUSIONS
  The results of this study suggest a suppressive effect of helium pneumoperitoneum on postoperative tumor growth and metastatic spread. Furthermore, tumor exposure to room air appears to have a stimulative influence on tumor recurrence and metastasis compared to a pneumoperitoneum established with CO2.
authors.affiliation: Surgical Department, University of Heidelberg, Im Neuenheimer Feld 110, D-69120 Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Schmeding
authors.forename: P
authors.initials: P
authors.lastname: Schwalbach
authors.forename: S
authors.initials: S
authors.lastname: Reinshagen
authors.forename: F
authors.initials: F
authors.lastname: Autschbach
authors.forename: A
authors.initials: A
authors.lastname: Benner
authors.forename: C
authors.initials: C
authors.lastname: Kuntz
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000009:adverse effects / Q000627:therapeutic use; D006528:Carcinoma, Hepatocellular / Q000556:secondary / Q000601:surgery*; D004195:Disease Models, Animal; D006371:Helium / Q000009:adverse effects* / Q000627:therapeutic use; D006498:Hepatectomy / Q000379:methods; D007327:Insufflation / Q000009:adverse effects / Q000379:methods; D010535:Laparoscopy / Q000379:methods*; D008114:Liver Neoplasms, Experimental / Q000601:surgery*; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000209:etiology*; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects* / Q000379:methods*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002245:Carbon Dioxide; D006371:Helium