title: Conditional survival in pancreatic cancer: better than expected.
abstract: BACKGROUND
  Traditional survival estimates after resection for pancreatic cancer are based on clinicopathological variables at the time of diagnosis. Estimates have not reflected time survived after resection, as investigated for other malignancies. The aim of the present study was to understand how survival estimates change after pancreatic resection for cancer based on time already survived (conditional survival).
  
  
  METHODS
  Pancreatectomies performed for pancreatic ductal adenocarcinoma (PDAC) between 2001 and 2010 were reviewed. Clinicopathological variables were evaluated to identify predictors of survival. Expected survival according to a validated nomogram for pancreatic cancer as well as conditional survival estimates and actual survival were calculated.
  
  
  RESULTS
  In all, 186 patients underwent pancreatic resection for PDAC [154 (82.8%) Whipple, 26 (14.0%) distal and 6 (3.2%) total]. Median (range) survival was 22 (3.4-107.3) months. Predictors of overall survival were: absence of nodal disease [odds ratio (OR) 8.8], age <67 years (OR 8.4) and lower stage (OR 4.3). Expected survival according to the nomogram was 70% (1 year), 39.5% (2 years) and 24% (3 years). As time passed, and overall and expected survival decreased, conditional survival increased.
  
  
  CONCLUSIONS
  The available prognostic system for PDAC underestimated survival compared with actual survival in the present study. Conditional survival estimates, based on accrued lifespan, were better than either predicted or actual survival, suggesting that survival is a dynamic, rather than static, concept. Conditional survival may, therefore, be a useful tool to allow patients and clinicians to project subsequent survival based on time accrued since resection.
authors.affiliation: Department of Surgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. tkent@bidmc.harvard.edu
authors.forename: Tara S
authors.initials: TS
authors.lastname: Kent
authors.forename: Teviah E
authors.initials: TE
authors.lastname: Sachs
authors.forename: Norberto
authors.initials: N
authors.lastname: Sanchez
authors.forename: Charles M
authors.initials: CM
authors.lastname: Vollmer
authors.forename: Mark P
authors.initials: MP
authors.lastname: Callery
mesh_terms: D000368:Aged; D001900:Boston / Q000453:epidemiology; D021441:Carcinoma, Pancreatic Ductal / Q000401:mortality* / Q000601:surgery*; D015987:Effect Modifier, Epidemiologic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D049451:Nomograms; D016017:Odds Ratio; D010180:Pancreatectomy / Q000009:adverse effects / Q000401:mortality*; D010190:Pancreatic Neoplasms / Q000401:mortality* / Q000601:surgery*; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome
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