title: Mapping patterns of local recurrence after pancreaticoduodenectomy for pancreatic adenocarcinoma: a new approach to adjuvant radiation field design.
abstract: OBJECTIVE
  To generate a map of local recurrences after pancreaticoduodenectomy (PD) for patients with resectable pancreatic ductal adenocarcinoma (PDA) and to model an adjuvant radiation therapy planning treatment volume (PTV) that encompasses a majority of local recurrences.
  
  
  METHODS
  Consecutive patients with resectable PDA undergoing PD and 1 or more computed tomography (CT) scans more than 60 days after PD at our institution were reviewed. Patients were divided into 3 groups: no adjuvant treatment (NA), chemotherapy alone (CTA), or chemoradiation (CRT). Cross-sectional scans were centrally reviewed, and local recurrences were plotted to scale with respect to the celiac axis (CA), superior mesenteric artery (SMA), and renal veins on 1 CT scan of a template post-PD patient. An adjuvant clinical treatment volume comprising 90% of local failures based on standard expansions of the CA and SMA was created and simulated on 3 post-PD CT scans to assess the feasibility of this planning approach.
  
  
  RESULTS
  Of the 202 patients in the study, 40 (20%), 34 (17%), and 128 (63%) received NA, CTA, and CRT adjuvant therapy, respectively. The rate of margin-positive resections was greater in CRT patients than in CTA patients (28% vs 9%, P=.023). Local recurrence occurred in 90 of the 202 patients overall (45%) and in 19 (48%), 22 (65%), and 49 (38%) in the NA, CTA, and CRT groups, respectively. Ninety percent of recurrences were within a 3.0-cm right-lateral, 2.0-cm left-lateral, 1.5-cm anterior, 1.0-cm posterior, 1.0-cm superior, and 2.0-cm inferior expansion of the combined CA and SMA contours. Three simulated radiation treatment plans using these expansions with adjustments to avoid nearby structures were created to demonstrate the use of this treatment volume.
  
  
  CONCLUSIONS
  Modified PTVs targeting high-risk areas may improve local control while minimizing toxicities, allowing dose escalation with intensity-modulated or stereotactic body radiation therapy.
authors.affiliation: Department of Radiation Oncology & Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Avani S
authors.initials: AS
authors.lastname: Dholakia
authors.forename: Rachit
authors.initials: R
authors.lastname: Kumar
authors.forename: Siva P
authors.initials: SP
authors.lastname: Raman
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Moore
authors.forename: Susannah
authors.initials: S
authors.lastname: Ellsworth
authors.forename: Todd
authors.initials: T
authors.lastname: McNutt
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Laheru
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Jaffee
authors.forename: John L
authors.initials: JL
authors.lastname: Cameron
authors.forename: Phuoc T
authors.initials: PT
authors.lastname: Tran
authors.forename: Robert F
authors.initials: RF
authors.lastname: Hobbs
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Wolfgang
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Herman
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D021441:Carcinoma, Pancreatic Ductal / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D016577:Pancreaticoduodenectomy; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D018714:Radiotherapy, Adjuvant / Q000379:methods; D020266:Radiotherapy, Conformal / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D047368:Tumor Burden