title: Conditional Probability of Long-term Survival After Liver Resection for Intrahepatic Cholangiocarcinoma: A Multi-institutional Analysis of 535 Patients.
abstract: OBJECTIVE
  Whereas conventional actuarial overall survival (OS) estimates rely exclusively on static factors determined around the time of surgery, conditional survival (CS) estimates take into account the years that a patient has already survived.
  
  
  OBJECTIVE
  To define the CS of patients following liver resection for intrahepatic cholangiocarcinoma (ICC).
  
  
  METHODS
  Between January 1, 1990, and December 31, 2013, a total of 535 patients who underwent resection of ICC were identified from an international multi-institutional database. In this retrospective international study conducted from January to June 2014, clinicopathological characteristics, operative details, and long-term survival data were analyzed. Conditional survival estimates were calculated as the probability of survival for an additional 3 years.
  
  
  METHODS
  Resection of ICC.
  
  
  METHODS
  Overall survival and CS.
  
  
  RESULTS
  While actuarial OS decreased over time from 39% at 3 years to 16% at 8 years (P = .002), the 3-year CS (CS₃) increased over time among those patients who survived. The CS₃ at 5 years-the probability of surviving to postoperative year 8 after having already survived to postoperative year 5-was 65% compared with 8-year OS of 16% (P = .002). Factors that were associated with worse OS included larger tumor size (hazard ratio [HR], 1.02; 95% CI, 1.00-1.05; P = .05), multifocal disease (HR, 1.49; 95% CI, 1.19-1.86; P = .01), lymph node metastasis (HR, 2.21; 95% CI, 1.67-2.93; P < .01), and vascular invasion (HR, 1.39; 95% CI, 1.10-1.75; P = .006). The calculated CS₃ exceeded the actuarial survival for all high-risk subgroups. For example, patients with lymph node metastasis had an actuarial OS of 11% at 6 years vs a CS₃ of 49% at 3 years (Δ38%). Similarly, patients with vascular invasion had an actuarial OS of 15% at 6 years compared with a CS₃ of 50% at 3 years (Δ35%).
  
  
  CONCLUSIONS
  Conditional survival estimates may provide critical quantitative information about the changing probability of survival over time among patients undergoing liver resection for ICC. Therefore, such estimates can be of significant value to patients and health care professionals.
authors.affiliation: Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Gaya
authors.initials: G
authors.lastname: Spolverato
authors.affiliation: Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Yuhree
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Aslam
authors.initials: A
authors.lastname: Ejaz
authors.affiliation: Institute for Digestive Diseases and Liver Transplantation Fundeni, Bucharest, Romania.
authors.forename: Sorin
authors.initials: S
authors.lastname: Alexandrescu
authors.affiliation: Curry Cabral Hospital, Lisbon, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Marques
authors.affiliation: Ospedale San Raffaele, Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Aldrighetti
authors.affiliation: Medical College of Wisconsin, Milwaukee.
authors.forename: T Clark
authors.initials: TC
authors.lastname: Gamblin
authors.affiliation: University of Sydney, Sydney, Australia.
authors.forename: Carlo
authors.initials: C
authors.lastname: Pulitano
authors.affiliation: University of Virginia, Charlottesville.
authors.forename: Todd W
authors.initials: TW
authors.lastname: Bauer
authors.affiliation: Eastern Hepatobiliary Surgery Hospital, Shanghai, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Shen
authors.affiliation: University of Sydney, Sydney, Australia.
authors.forename: Charbel
authors.initials: C
authors.lastname: Sandroussi
authors.affiliation: Stanford University, Palo Alto, California.
authors.forename: George
authors.initials: G
authors.lastname: Poultsides
authors.affiliation: Emory University, Atlanta, Georgia.
authors.forename: Shishir K
authors.initials: SK
authors.lastname: Maithel
authors.affiliation: Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pawlik
mesh_terms: D000368:Aged; D001650:Bile Duct Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D005260:Female; D006498:Hepatectomy; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis