title: Surgeon specialization and use of sentinel lymph node biopsy for breast cancer.
abstract: OBJECTIVE
  Sentinel lymph node biopsy (SLNB) is the standard of care for axillary staging in patients with clinically node-negative breast cancer. It is not known whether SLNB rates differ by surgeon expertise. If surgeons with less breast cancer expertise are less likely to offer SLNB to these patients, this practice pattern could lead to unnecessary axillary lymph node dissections and lymphedema.
  
  
  OBJECTIVE
  To explore potential measures of surgical expertise (including a novel objective specialization measure: percentage of a surgeon's operations performed for breast cancer determined from Medicare claims) on the use of SLNB for invasive breast cancer.
  
  
  METHODS
  A population-based prospective cohort study was conducted in California, Florida, and Illinois. Participants included elderly (65-89 years) women identified from Medicare claims as having had incident invasive breast cancer surgery in 2003. Patient, tumor, treatment, and surgeon characteristics were examined.
  
  
  METHODS
  Type of axillary surgery performed.
  
  
  RESULTS
  Of 1703 women who received treatment by 863 surgeons, 56.4% underwent an initial SLNB, 37.2% initial axillary lymph node dissection, and 6.3% no axillary surgery. The median annual surgeon Medicare volume of breast cancer cases was 6.0 (range, 1.5-57.0); the median surgeon percentage of breast cancer cases was 4.5% (range, 0.4%-100.0%). After multivariable adjustment of patient and surgeon factors, women operated on by surgeons with higher volumes and percentages of breast cancer cases had a higher likelihood of undergoing SLNB. Specifically, women were most likely to undergo SLNB if the operation was performed by high-volume surgeons (regardless of percentage) or by lower-volume surgeons with a high percentage of breast cancer cases. In addition, membership in the American Society of Breast Surgeons (odds ratio, 1.98; 95% CI, 1.51-2.60) and Society of Surgical Oncology (1.59; 1.09-2.30) were independent predictors of women undergoing an initial SLNB.
  
  
  CONCLUSIONS
  Patients who receive treatment from surgeons with more experience with and focus on breast cancer are significantly more likely to undergo SLNB, highlighting the importance of receiving initial treatment by specialized providers. Factors relating to specialization in a particular area, including our novel surgeon percentage measure, require further investigation as potential indicators of quality of care.
authors.affiliation: Division of Surgical Oncology, Center for Patient Care and Outcomes Research, Medical College of Wisconsin, Milwaukee.
authors.forename: Tina W F
authors.initials: TW
authors.lastname: Yen
authors.affiliation: Division of Biostatistics, Center for Patient Care and Outcomes Research, Medical College of Wisconsin, Milwaukee.
authors.forename: Purushuttom W
authors.initials: PW
authors.lastname: Laud
authors.affiliation: Division of Biostatistics, Center for Patient Care and Outcomes Research, Medical College of Wisconsin, Milwaukee.
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Sparapani
authors.affiliation: Department of Medicine, Center for Patient Care and Outcomes Research, Medical College of Wisconsin, Milwaukee.
authors.forename: Ann B
authors.initials: AB
authors.lastname: Nattinger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000556:secondary / Q000601:surgery*; D002983:Clinical Competence; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000592:standards; D008207:Lymphatic Metastasis; D008297:Male; D009367:Neoplasm Staging / Q000379:methods*; D010820:Physicians / Q000592:standards*; D011446:Prospective Studies; D012042:Registries; D021701:Sentinel Lymph Node Biopsy / Q000592:standards / Q000706:statistics & numerical data*; D013038:Specialization; D013043:Specialties, Surgical / Q000592:standards*; D014481:United States