title: Postradiotherapy CA19-9 kinetics correlate with outcomes in patients with pancreatic adenocarcinoma.
abstract: OBJECTIVE
  We sought to determine if carbohydrate antigen 19-9 (CA19-9 ) nadir (nCA19-9), time to nadir (TTN), and doubling time (DT) after radiotherapy (RT) correlate with outcomes in pancreatic ductal adenocarcinoma.
  
  
  METHODS
  We examined the records of 102 patients treated with RT for primary, nonmetastatic pancreatic ductal adenocarcinoma between August 1998 and July 2011. Of these, 33 patients were treated with postoperative chemoradiotherapy (PORT) and 69 patients with definitive chemoradiotherapy (CRT).
  
  
  RESULTS
  Among the patients treated with PORT, TTN and DT were associated with both overall survival (OS; P = <0.01 for both) and freedom from progression (FFP; P = <0.01 for both). In patients treated with CRT, nCA19-9 and TTN correlated with both OS (P = <0.01 and P = 0.02, respectively) and FFP (P = 0.01 and <0.01, respectively). On multivariable analysis, in patients treated with PORT, TTN remained independently correlated with OS and FFP (P = 0.01; hazard ratios [HR], 6.43 and P = 0.02; HR, 4.00, respectively), whereas DT remained independently correlated to FFP (P = 0.04; HR, 0.27). In patients treated with CRT, controlling for pretreatment CA19-9, nCA19-9 and TTN independently correlated with OS (P = <0.01; HR, 3.0 and P = 0.03; HR, 2.56, respectively) and FFP (P = 0.04; HR, 2.31 and P = <0.01; HR, 4.0, respectively).
  
  
  CONCLUSIONS
  CA19-9 kinetics after RT correlate with disease progression and survival and could serve as a prognostic tool to guide treatment decisions.
authors.affiliation: From the *Department of Radiation Oncology, and †Division of Oncology, Department of Medicine, Stanford University; and ‡Stanford Cancer Institute, Stanford, CA.
authors.forename: David B
authors.initials: DB
authors.lastname: Shultz
authors.forename: Cato
authors.initials: C
authors.lastname: Chan
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Shaffer
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Kunz
authors.forename: Albert C
authors.initials: AC
authors.lastname: Koong
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Chang
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018395:CA-19-9 Antigen / Q000032:analysis*; D021441:Carcinoma, Pancreatic Ductal / Q000601:surgery / Q000628:therapy*; D059248:Chemoradiotherapy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D010190:Pancreatic Neoplasms / Q000601:surgery / Q000628:therapy*; D016016:Proportional Hazards Models; D012189:Retrospective Studies
chemical_list: D018395:CA-19-9 Antigen