title: Time-dependent impact of age and comorbidities on long-term overall survival after liver resection.
abstract: Advanced age and comorbidities are known to be associated with increased perioperative risks after liver resection. However, the precise impact of these variables on long-term overall survival (OS) remains unclear. Thus, the aim of this study was to evaluate the confounder-adjusted, time-dependent effect of age and comorbidities on OS following hepatectomy for primary and secondary malignancies.
  
  
  
  From a prospective database of 1.143 liver resections, 763 patients treated for primary and secondary malignancies were included. For time-varying OS calculations, a Cox-Aalen model was fitted. The confounder-adjusted hazard was compared with mortality tables of the German population.
  
  
  
  Overall, age (P = 0.003) and comorbidities (P = 0.001) were associated with shortened OS. However, time-dependent analysis indicated that age and comorbidities had no impact on OS within 39 and 55 months after resection respectively. From this time on, a significant decline in OS was shown. Subgroup analysis indicated an earlier increase of the effect of age in patients with hepatocellular carcinoma (17 months) than in those with colorectal metastases (70 months). The confounder-adjusted hazard of 70-year-old patients was increased post-operatively but dropped 66 months after surgery, and the risk of death was comparable to the general population 78 months after resection. At this time, one-third of patients aged 70 years and older were still alive.
  
  
  
  With regard to long-term outcome, liver resection for both primary and secondary malignancies should not be categorically denied due to age and comorbidities. This information should be considered for the patient selection process and informed consent.
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Tobias S
authors.initials: TS
authors.lastname: Schiergens
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lindenthaler
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Thomas
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Rentsch
authors.affiliation: Statistical Consulting Unit, Department of Statistics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Mittermeier
authors.affiliation: Statistical Consulting Unit, Department of Statistics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Brand
authors.affiliation: Statistical Consulting Unit, Department of Statistics, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Küchenhoff
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Serene
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Guba
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Werner
authors.affiliation: Department of General, Visceral, Transplantation, Vascular and Thoracic Surgery, Hospital of the University of Munich, Munich, Germany.
authors.forename: Wolfgang E
authors.initials: WE
authors.lastname: Thasler
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D015179:Colorectal Neoplasms / Q000556:secondary; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D005858:Germany; D006498:Hepatectomy; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018579:Patient Selection; D011446:Prospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cox-Aalen model; age; comorbidities; liver resection; time-varying coefficients