title: Single- versus multifraction stereotactic body radiation therapy for pancreatic adenocarcinoma: outcomes and toxicity.
abstract: OBJECTIVE
  We report updated outcomes of single- versus multifraction stereotactic body radiation therapy (SBRT) for unresectable pancreatic adenocarcinoma.
  
  
  METHODS
  We included 167 patients with unresectable pancreatic adenocarcinoma treated at our institution from 2002 to 2013, with 1-fraction (45.5% of patient) or 5-fraction (54.5% of patients) SBRT. The majority of patients (87.5%) received chemotherapy.
  
  
  RESULTS
  Median follow-up was 7.9 months (range: 0.1-63.6). The 6- and 12-month cumulative incidence rates (CIR) of local recurrence for patients treated with single-fraction SBRT were 5.3% (95% confidence interval [CI], 0.2%-10.4%) and 9.5% (95% CI, 2.7%-16.2%), respectively. The 6- and 12-month CIR with multifraction SBRT were 3.4% (95% CI, 0.0-7.2%) and 11.7% (95% CI, 4.8%-18.6%), respectively. Median survival from diagnosis for all patients was 13.6 months (95% CI, 12.2-15.0 months). The 6- and 12- month survival rates from SBRT for the single-fraction group were 67.0% (95% CI, 57.2%-78.5%) and 30.8% (95% CI, 21.9%-43.6%), respectively. The 6- and 12- month survival rates for the multifraction group were 75.7% (95% CI, 67.2%-85.3%) and 34.9% (95% CI, 26.1%-46.8%), respectively. There were no differences in CIR or survival rates between the single- and multifraction groups. The 6- and 12-month cumulative incidence rates of gastrointestinal toxicity grade ≥3 were 8.1% (95% CI, 1.8%-14.4%) and 12.3% (95% CI, 4.7%-20.0%), respectively, in the single-fraction group, and both were 5.6% (95% CI, 0.8%-10.5%) in the multifraction group. There were significantly fewer instances of toxicity grade ≥2 with multifraction SBRT (P=.005). Local recurrence and toxicity grade ≥2 were independent predictors of worse survival.
  
  
  CONCLUSIONS
  Multifraction SBRT for pancreatic cancer significantly reduces gastrointestinal toxicity without compromising local control.
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
authors.forename: Erqi L
authors.initials: EL
authors.lastname: Pollom
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
authors.forename: Muthuraman
authors.initials: M
authors.lastname: Alagappan
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
authors.forename: Rie
authors.initials: R
authors.lastname: von Eyben
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California.
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Kunz
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California.
authors.forename: George A
authors.initials: GA
authors.lastname: Fisher
authors.affiliation: Department of Medicine, Stanford University School of Medicine, Stanford, California.
authors.forename: James A
authors.initials: JA
authors.lastname: Ford
authors.affiliation: Department of Surgery, Stanford University School of Medicine, Stanford, California.
authors.forename: George A
authors.initials: GA
authors.lastname: Poultsides
authors.affiliation: Department of Surgery, Stanford University School of Medicine, Stanford, California.
authors.forename: Brendan C
authors.initials: BC
authors.lastname: Visser
authors.affiliation: Department of Surgery, Stanford University School of Medicine, Stanford, California.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Norton
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, California.
authors.forename: Aya
authors.initials: A
authors.lastname: Kamaya
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, California.
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Cox
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Columbo
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
authors.forename: Albert C
authors.initials: AC
authors.lastname: Koong
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California. Electronic address: dtchang@stanford.edu.
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Chang
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D015996:Survival Rate; D016896:Treatment Outcome