title: The impact of radiation therapy on the risk of lymphedema after treatment for breast cancer: a prospective cohort study.
abstract: OBJECTIVE
  Lymphedema after breast cancer treatment can be an irreversible condition with a negative impact on quality of life. The goal of this study was to identify radiation therapy-related risk factors for lymphedema.
  
  
  METHODS
  From 2005 to 2012, we prospectively performed arm volume measurements on 1476 breast cancer patients at our institution using a Perometer. Treating each breast individually, 1099 of 1501 patients (73%) received radiation therapy. Arm measurements were performed preoperatively and postoperatively. Lymphedema was defined as ≥10% arm volume increase occurring >3 months postoperatively. Univariate and multivariate Cox proportional hazard models were used to evaluate risk factors for lymphedema.
  
  
  RESULTS
  At a median follow-up time of 25.4 months (range, 3.4-82.6 months), the 2-year cumulative incidence of lymphedema was 6.8%. Cumulative incidence by radiation therapy type was as follows: 3.0% no radiation therapy, 3.1% breast or chest wall alone, 21.9% supraclavicular (SC), and 21.1% SC and posterior axillary boost (PAB). On multivariate analysis, the hazard ratio for regional lymph node radiation (RLNR) (SC ± PAB) was 1.7 (P=.025) compared with breast/chest wall radiation alone. There was no difference in lymphedema risk between SC and SC + PAB (P=.96). Other independent risk factors included early postoperative swelling (P<.0001), higher body mass index (P<.0001), greater number of lymph nodes dissected (P=.018), and axillary lymph node dissection (P=.0001).
  
  
  CONCLUSIONS
  In a large cohort of breast cancer patients prospectively screened for lymphedema, RLNR significantly increased the risk of lymphedema compared with breast/chest wall radiation alone. When considering use of RLNR, clinicians should weigh the potential benefit of RLNR for control of disease against the increased risk of lymphedema.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Laura E G
authors.initials: LE
authors.lastname: Warren
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Miller
authors.affiliation: Department of Biostatistics, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Nora
authors.initials: N
authors.lastname: Horick
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Melissa N
authors.initials: MN
authors.lastname: Skolny
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Lauren S
authors.initials: LS
authors.lastname: Jammallo
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Betro T
authors.initials: BT
authors.lastname: Sadek
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Mina N
authors.initials: MN
authors.lastname: Shenouda
authors.affiliation: Department of Physical and Occupational Therapy, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Jean A
authors.initials: JA
authors.lastname: O'Toole
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: MacDonald
authors.affiliation: Division of Surgical Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Specht
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts. Electronic address: ataghian@partners.org.
authors.forename: Alphonse G
authors.initials: AG
authors.lastname: Taghian
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001365:Axilla; D015992:Body Mass Index; D001941:Breast Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision / Q000009:adverse effects; D015182:Lymphatic Irradiation / Q000009:adverse effects*; D008209:Lymphedema / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult