title: Radiation field design and patterns of locoregional recurrence following definitive radiotherapy for breast cancer.
abstract: OBJECTIVE
  Locoregional control is associated with breast cancer-specific and overall survival in select women with breast cancer. Although several patient, tumor, and treatment characteristics have been shown to contribute to locoregional recurrence (LRR), studies evaluating factors related to radiotherapy (XRT) technique have been limited. We investigated the relationship between LRR location and XRT fields and dose delivered to the primary breast cancer in women experiencing subsequent locoregional relapse.
  
  
  METHODS
  We identified 21 women who were previously treated definitively with surgery and XRT for breast cancer. All patients developed biopsy-result proven LRR and presented to Emory University Hospital between 2004 and 2010 for treatment. Computed tomography (CT) simulation scans with XRT dose files for the initial breast cancer were fused with (18)F-labeled fluorodeoxyglucose positron emission tomography (FDG PET)/CT images in DICOM (Digital Imaging and Communications in Medicine) format identifying the LRR. Each LRR was categorized as in-field, defined as ≥95% of the LRR volume receiving ≥95% of the prescribed whole-breast dose; marginal, defined as LRR at the field edge and/or not receiving ≥95% of the prescribed dose to ≥95% of the volume; or out-of-field, that is, LRR intentionally not treated with the original XRT plan.
  
  
  RESULTS
  Of the 24 identified LRRs (3 patients experienced two LRRs), 3 were in-field, 9 were marginal, and 12 were out-of-field. Two of the 3 in-field LRRs were marginal misses of the additional boost XRT dose. Out-of-field LRRs consisted of six supraclavicular and six internal mammary nodal recurrences.
  
  
  CONCLUSIONS
  Most LRRs in our study occurred in areas not fully covered by the prescribed XRT dose or were purposely excluded from the original XRT fields. Our data suggest that XRT technique, field design, and dose play a critical role in preventing LRR in women with breast cancer.
authors: Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia, USA.
authors: Susie A
authors: SA
authors: Chen
authors: David M
authors: DM
authors: Schuster
authors: Donna
authors: D
authors: Mister
authors: Tian
authors: T
authors: Liu
authors: Karen
authors: K
authors: Godette
authors: Mylin A
authors: MA
authors: Torres
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D018572:Disease-Free Survival; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009363:Neoplasm Proteins / Q000032:analysis; D009364:Neoplasm Recurrence, Local / Q000737:chemistry / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18; D009363:Neoplasm Proteins; D019275:Radiopharmaceuticals; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone