title: Incidence of unilateral arm lymphoedema after breast cancer: a systematic review and meta-analysis.
abstract: BACKGROUND
  The body of evidence related to breast-cancer-related lymphoedema incidence and risk factors has substantially grown and improved in quality over the past decade. We assessed the incidence of unilateral arm lymphoedema after breast cancer and explored the evidence available for lymphoedema risk factors.
  
  
  METHODS
  We searched Academic Search Elite, Cumulative Index to Nursing and Allied Health, Cochrane Central Register of Controlled Trials (clinical trials), and Medline for research articles that assessed the incidence or prevalence of, or risk factors for, arm lymphoedema after breast cancer, published between Jan 1, 2000, and June 30, 2012. We extracted incidence data and calculated corresponding exact binomial 95% CIs. We used random effects models to calculate a pooled overall estimate of lymphoedema incidence, with subgroup analyses to assess the effect of different study designs, countries of study origin, diagnostic methods, time since diagnosis, and extent of axillary surgery. We assessed risk factors and collated them into four levels of evidence, depending on consistency of findings and quality and quantity of studies contributing to findings.
  
  
  RESULTS
  72 studies met the inclusion criteria for the assessment of lymphoedema incidence, giving a pooled estimate of 16.6% (95% CI 13.6-20.2). Our estimate was 21.4% (14.9-29.8) when restricted to data from prospective cohort studies (30 studies). The incidence of arm lymphoedema seemed to increase up to 2 years after diagnosis or surgery of breast cancer (24 studies with time since diagnosis or surgery of 12 to <24 months; 18.9%, 14.2-24.7), was highest when assessed by more than one diagnostic method (nine studies; 28.2%, 11.8-53.5), and was about four times higher in women who had an axillary-lymph-node dissection (18 studies; 19.9%, 13.5-28.2) than it was in those who had sentinel-node biopsy (18 studies; 5.6%, 6.1-7.9). 29 studies met the inclusion criteria for the assessment of risk factors. Risk factors that had a strong level of evidence were extensive surgery (ie, axillary-lymph-node dissection, greater number of lymph nodes dissected, mastectomy) and being overweight or obese.
  
  
  CONCLUSIONS
  Our findings suggest that more than one in five women who survive breast cancer will develop arm lymphoedema. A clear need exists for improved understanding of contributing risk factors, as well as of prevention and management strategies to reduce the individual and public health burden of this disabling and distressing disorder.
  
  
  BACKGROUND
  The National Breast Cancer Foundation, Australia.
authors.affiliation: School of Public Health and Social Work, Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland, Australia. t.disipio@qut.edu.au
authors.forename: Tracey
authors.initials: T
authors.lastname: DiSipio
authors.forename: Sheree
authors.initials: S
authors.lastname: Rye
authors.forename: Beth
authors.initials: B
authors.lastname: Newman
authors.forename: Sandi
authors.initials: S
authors.lastname: Hayes
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D005260:Female; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision / Q000009:adverse effects*; D008209:Lymphedema / Q000453:epidemiology* / Q000473:pathology; D008408:Mastectomy / Q000009:adverse effects*; D016017:Odds Ratio; D050177:Overweight / Q000453:epidemiology; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D034941:Upper Extremity / Q000473:pathology*