title: Long-term survival after colon cancer surgery: a variation associated with choice of anesthesia.
abstract: BACKGROUND
  A previously published clinical trial of epidural-supplemented versus general anesthesia, Veterans Affairs Cooperative Study No. 345, showed no difference in 30-day mortality and morbidity rates between the two treatments. We hypothesized that long-term postoperative survival would be increased by epidural anesthesia/analgesia supplementation during colon cancer resection.
  
  
  METHODS
  We studied long-term survival after resection of colon cancer in a trial of general anesthesia with and without epidural anesthesia and analgesia supplementation for resection of colon cancer in Veterans Affairs Cooperative Study No. 345. Cox and log-normal survival models were used to test the effects of pathological stage, type of anesthesia and other covariates on survival in 177 patients.
  
  
  RESULTS
  The presence of distant metastases had the greatest effect on survival. Thus, analyses were performed separately for patients with and without metastases. For those without metastasis, the hazard ratio for the treatment effects changed at 1.46 years. Before 1.46 years, epidural supplementation was associated with improved survival (P = 0.012), while later, the type of anesthesia did not appear to affect survival (P = 0.27). Hypertension was associated with poorer survival (P = 0.029), as was alcoholism in patients who received epidural anesthesia (P = 0.014). Survival of patients with metastases was unaffected by type of anesthesia. There was a significant age by hypertension interaction (P = 0.002). Patients survived longer if they were hypertensive, but had reduced survival if they were older than 66 years and hypertensive.
  
  
  CONCLUSIONS
  Epidural supplementation was associated with enhanced survival among patients without metastases before 1.46 years. Epidural anesthesia had no effect on survival of patients with metastases. Additional studies to confirm or refute these findings are warranted.
authors.affiliation: Anesthesiology Service, VA Medical Center and Department of Anesthesiology, OR Health and Science University, Portland, OR 97229, USA. rose.christopherson@med.va.gov
authors.forename: Rose
authors.initials: R
authors.lastname: Christopherson
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: James
authors.forename: Mara
authors.initials: M
authors.lastname: Tableman
authors.forename: Prudence
authors.initials: P
authors.lastname: Marshall
authors.forename: Frank E
authors.initials: FE
authors.lastname: Johnson
mesh_terms: D000367:Age Factors; D000368:Aged; D000437:Alcoholism / Q000150:complications; D000767:Anesthesia, Epidural / Q000379:methods*; D003110:Colonic Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D006801:Humans; D006973:Hypertension / Q000150:complications; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011336:Probability; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic