title: Comparison of depth of necrosis achieved by CO2- and N2O-cryotherapy.
abstract: OBJECTIVE
  To compare the depth of necrosis achieved using CO2- and N2O-cryotherapy.
  
  
  METHODS
  We treated 20 women with CO2-cryotherapy and 20 with N2O-cryotherapy 24 h prior to undergoing total hysterectomy for reasons unrelated to cervical cancer. Depth of necrosis in the ectocervix was measured on surgically removed tissue.
  
  
  RESULTS
  The mean depth of necrosis for the anterior lip achieved by N2O-cryotherapy was 5.3 mm compared with 3.4 mm by CO2-cryotherapy (P<0.001). We found similar results for the posterior lip (5.0 vs 3.1 mm; P<0.001). N2O-cryotherapy was more likely than CO2-cryotherapy to achieve a depth of necrosis of >or=4.8 mm for the anterior lip (75% vs 15%; P<0.001) and posterior lip (60% vs 5%; P<0.001).
  
  
  CONCLUSIONS
  Our study showed that CO2-cryotherapy may not achieve the depth of necrosis necessary to completely destroy cervical precancer and therefore may be less robust than N2O-cryotherapy.
authors: Instituto de Enfermedades Neoplasicas, Lima, Peru.
authors: J
authors: J
authors: Mariategui
authors: C
authors: C
authors: Santos
authors: L
authors: L
authors: Taxa
authors: J
authors: J
authors: Jeronimo
authors: P E
authors: PE
authors: Castle
mesh_terms: D002245:Carbon Dioxide / Q000627:therapeutic use; D002584:Cervix Uteri / Q000601:surgery*; D019092:Conization / Q000379:methods*; D017679:Cryotherapy / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009336:Necrosis / Q000139:chemically induced; D009609:Nitrous Oxide / Q000627:therapeutic use; D002583:Uterine Cervical Neoplasms / Q000628:therapy*; D002578:Uterine Cervical Dysplasia / Q000628:therapy*
chemical_list: D002245:Carbon Dioxide; D009609:Nitrous Oxide