title: Adjuvant Radiation Therapy Treatment Time Impacts Overall Survival in Gastric Cancer.
abstract: OBJECTIVE
  Prolonged radiation therapy treatment time (RTT) is associated with worse survival in several tumor types. This study investigated whether delays during adjuvant radiation therapy impact overall survival (OS) in gastric cancer.
  
  
  METHODS
  The National Cancer Data Base was queried for patients with resected gastric cancer who received adjuvant radiation therapy with National Comprehensive Cancer Network--recommended doses (45 or 50.4 Gy) between 1998 and 2006. RTT was classified as standard (45 Gy: 33-36 days, 50.4 Gy: 38-41 days) or prolonged (45 Gy: >36 days, 50.4 Gy: >41 days). Cox proportional hazards models evaluated the association between the following factors and OS: RTT, interval from surgery to radiation therapy initiation, interval from surgery to radiation therapy completion, radiation therapy dose, demographic/pathologic and operative factors, and other elements of adjuvant multimodality therapy.
  
  
  RESULTS
  Of 1591 patients, RTT was delayed in 732 (46%). Factors associated with prolonged RTT were non-private health insurance (OR 1.3, P=.005) and treatment at non-academic facilities (OR 1.2, P=.045). Median OS and 5-year actuarial survival were significantly worse in patients with prolonged RTT compared with standard RTT (36 vs 51 months, P=.001; 39 vs 47%, P=.005); OS worsened with each cumulative week of delay (P<.0004). On multivariable analysis, prolonged RTT was associated with inferior OS (hazard ratio 1.2, P=.002); the intervals from surgery to radiation therapy initiation or completion were not. Prolonged RTT was particularly detrimental in patients with node positivity, inadequate nodal staging (<15 nodes examined), and those undergoing a cycle of chemotherapy before chemoradiation therapy.
  
  
  CONCLUSIONS
  Delays during adjuvant radiation therapy appear to negatively impact survival in gastric cancer. Efforts to minimize cumulative interruptions to <7 days should be considered.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania; Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: McMillan
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Eric
authors.initials: E
authors.lastname: Ojerholm
authors.affiliation: Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania. Electronic address: Robert.Roses@uphs.upenn.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Roses
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: John P
authors.initials: JP
authors.lastname: Plastaras
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: James M
authors.initials: JM
authors.lastname: Metz
authors.affiliation: Department of Hematology/Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Ronac
authors.initials: R
authors.lastname: Mamtani
authors.affiliation: Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Giorgos C
authors.initials: GC
authors.lastname: Karakousis
authors.affiliation: Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Fraker
authors.affiliation: Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Drebin
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Diana
authors.initials: D
authors.lastname: Stripp
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Edgar
authors.initials: E
authors.lastname: Ben-Josef
authors.affiliation: Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.
authors.forename: Jashodeep
authors.initials: J
authors.lastname: Datta
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000532:radiotherapy* / Q000601:surgery; D016019:Survival Analysis; D013997:Time Factors