title: High-resolution lymphoscintigraphy is essential for recognition of the significance of internal mammary nodes in breast cancer.
abstract: BACKGROUND
  Sentinel node biopsy (SNB) of internal mammary nodes (IMNs) in breast cancer is controversial. Most centers rarely identify IMN on lymphoscintigraphy but others report up to 45% of cases. Controversy relates to the technique of lymphatic mapping, safety of IMN SNB, the significance of positive IMN, and potential to impact survival.
  
  
  METHODS
  Assessment of drainage rates from two unrelated nuclear medicine departments' databases. Review of related literature.
  
  
  RESULTS
  High-resolution lymphoscintigraphy results in IMN drainage in one-third of breast cancers. There is a learning curve for the technique. In 1754 consecutive cases, internal mammary drainage occurred in 53% of medial tumors, 37% midline tumors and 24% of lateral tumors (overall 34%). Extended radical mastectomy series also demonstrate the (approximately) 1/3 ratio when comparing IMN positivity rates to axillary node positivity rates (18.8% : 48.3%) and in node-positive patients (31% : 100%). The management altering potential of IMN assessment and potential survival impact are discussed.
  
  
  CONCLUSIONS
  IMN mapping gives information that alters management in up to one-third of cases. These rates of IMN drainage are reproducible and reflect lymphatic density and anatomy of the breast. A priority need exists to establish a collaborative clinical trial to clarify the value of IMN assessment.
authors.affiliation: Department of Surgical Oncology, The University of Sydney, Sydney, Australia. andrew.spillane@smu.org.au
authors.forename: A J
authors.initials: AJ
authors.lastname: Spillane
authors.forename: F
authors.initials: F
authors.lastname: Noushi
authors.forename: R A
authors.initials: RA
authors.lastname: Cooper
authors.forename: V
authors.initials: V
authors.lastname: Gebski
authors.forename: R F
authors.initials: RF
authors.lastname: Uren
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis; D011877:Radionuclide Imaging; D013909:Thorax