title: Does axillary boost increase lymphedema compared with supraclavicular radiation alone after breast conservation?
abstract: OBJECTIVE
  To determine independent predictors of lymphedema (LE) after breast radiotherapy and to quantify added risks of LE from regional node irradiation (RNI).
  
  
  METHODS
  A total of 2,579 women with T1-2, N 0-3, M0 breast cancer treated with breast conservation between 1970 and 2005 were studied. A total of 2,169 patients (84%) received radiation to the breast (B), 226 (8.8%) to the breast and supraclavicular LNs (B+SC), and 184 (7.1%) to the breast, supraclavicular LNs, and a posterior axillary boost (B+SC+PAB). Median follow-up was 81 months (range, 3-271).
  
  
  RESULTS
  Eighteen percent of patients developed LE. LE risks were as follows: 16% (B), 23% (B+SC), and 31% (B+SC+PAB) (p < 0.0001). LE severity was greater in patients who had RNI (p = 0.0002). On multivariate analysis, RT field (p < 0.0001), obesity index (p = 0.0157), systemic therapy (p = 0.0013), and number of LNs dissected (p < 0.0001) independently predicted for LE. In N1 patients, the addition of a SC to tangents (p < 0.0001) and the addition of a PAB to tangents (p = 0.0017) conferred greater risks of LE, but adding a PAB to B+SC RT did not (p = 0.8002). In the N2 patients, adding a PAB increased the risk of LE 4.5-fold over B+SC RT (p = 0.0011).
  
  
  CONCLUSIONS
  LE predictors included number of LNs dissected, RNI, obesity index, and systemic therapy. LE risk increased when a SC or PAB were added in the N1 subgroup. In the N2 patients, a PAB increased the risk over B+SC. The decision to boost the axilla must be weighed against the increased risk of LE that it imposes.
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA.
authors.forename: Shelly B
authors.initials: SB
authors.lastname: Hayes
authors.forename: Gary M
authors.initials: GM
authors.lastname: Freedman
authors.forename: Tianyu
authors.initials: T
authors.lastname: Li
authors.forename: Penny R
authors.initials: PR
authors.lastname: Anderson
authors.forename: Eric
authors.initials: E
authors.lastname: Ross
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla / Q000473:pathology; D001943:Breast Neoplasms / Q000453:epidemiology / Q000503:physiopathology / Q000532:radiotherapy* / Q000601:surgery*; D002968:Clavicle; D003131:Combined Modality Therapy / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008209:Lymphedema / Q000453:epidemiology*; D015412:Mastectomy, Segmental / Q000009:adverse effects*; D008875:Middle Aged; D009367:Neoplasm Staging; D011788:Quality of Life; D011878:Radiotherapy / Q000009:adverse effects; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult