title: Stereotactic body radiotherapy (SBRT) in recurrent or oligometastatic pancreatic cancer : A toxicity review of simultaneous integrated protection (SIP) versus conventional SBRT.
abstract: BACKGROUND
  Stereotactic body radiotherapy (SBRT) in pancreatic cancer can be limited by its proximity to organs at risk (OAR). In this analysis, we evaluated the toxicity and efficacy of two different treatment approaches in patients with locally recurrent or oligometastatic pancreatic cancer.
  
  
  METHODS
  According to the prescription method, patients were divided in two cohorts (C1 and C2). The planning target volume (PTV) was created through a 4 mm expansion of the internal target volume. In C2, a subvolume was additionally created, a simultaneous integrated protection (SIP), which is the overlap of the PTV with the planning risk volume of an OAR to which we prescribed a reduced dose.
  
  
  RESULTS
  In all, 18 patients were treated (7 with local recurrences, 9 for oligometastases, 2 for both). Twelve of 23 lesions were treated without SIP (C1) and 11 with SIP (C2). The median follow-up was 12.8 months. Median overall survival (OS) was 13.2 (95% confidence interval [CI] 9.8-14.6) months. The OS rates at 6 and 12 months were 87 and 58%, respectively. Freedom from local progression for combined cohorts at 6 and 12 months was 93 and 67% (95% CI 15-36), respectively. Local control was not statistically different between the two groups. One patient in C2 experienced grade ≥3 acute toxicities and 1 patient in C1 experienced a grade ≥3 late toxicity.
  
  
  CONCLUSIONS
  The SIP approach is a useful prescription method for abdominal SBRT with a favorable toxicity profile which does not compromise local control and overall survival despite dose sacrifices in small subvolumes.
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany. eleni.gkika@uniklinik-freiburg.de.
authors.forename: E
authors.initials: E
authors.lastname: Gkika
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany.|German Cancer Consortium (DKTK), Heidelberg (partner site Freiburg), Germany.
authors.forename: S
authors.initials: S
authors.lastname: Adebahr
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kirste
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schimek-Jasch
authors.affiliation: Division of Medical Physics, Department of Radiation Oncology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Wiehle
authors.affiliation: Department of Hematology, Oncology and Stem-Cell Transplantation, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Claus
authors.affiliation: Department of General and Visceral Surgery, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Wittel
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany.|German Cancer Consortium (DKTK), Heidelberg (partner site Freiburg), Germany.|Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Nestle
authors.affiliation: Division of Medical Physics, Department of Radiation Oncology, University Medical Center Freiburg, Freiburg, Germany.|German Cancer Consortium (DKTK), Heidelberg (partner site Freiburg), Germany.|Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Baltas
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany.|German Cancer Consortium (DKTK), Heidelberg (partner site Freiburg), Germany.|Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: A L
authors.initials: AL
authors.lastname: Grosu
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg im Breisgau, Germany.|German Cancer Consortium (DKTK), Heidelberg (partner site Freiburg), Germany.|Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: T B
authors.initials: TB
authors.lastname: Brunner
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003131:Combined Modality Therapy; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D009367:Neoplasm Staging; D058958:Organs at Risk / Q000528:radiation effects; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000072078:Positron Emission Tomography Computed Tomography; D011835:Radiation Protection / Q000379:methods*; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
keywords: Local progression; Overall survival; Prognosis; Radiation therapy; Toxicity