title: Intraoperative radiocolloid injection for sentinel node biopsy postneoadjuvant chemotherapy.
abstract: BACKGROUND
  This study sought to determine significance of radiocolloid injection timing for sentinel node biopsy (SNB) after neoadjuvant chemotherapy (NAC).
  
  
  METHODS
  A retrospective comparison of intraoperative (IRCI) and preoperative (PRCI) radiocolloid injection for SNB was performed in breast cancer patients who had completed NAC. The sentinel node identification rate (SNIDR) was tested for noninferiority by a two-proportion z-test. The differences between clinical demographics, pathologic demographics, and SNIDR were evaluated by Fisher exact test. The difference in the number of sentinel nodes removed was analyzed by two-sample t-test.
  
  
  RESULTS
  In the 6-y study period, 120 SNB were performed after NAC: 84 received PRCI and 36 received IRCI. The two groups were similar except there were fewer clinical T2 and more clinical T3 and T4 with IRCI (P = 0.0008). The SNIDR was 92.9% with PRCI and 80.6% with IRCI. By two-proportion z-test, IRCI was not "noninferior" (P = 0.5179). By Fisher exact test, the SNIDR of the two groups did not differ. The SNIDR differs only in patients who experience T downstaging (100% versus 80%, P = 0.0173). The mean number of lymph nodes removed was higher with IRCI: 3.38 versus 2.49 nodes (P = 0.0068). There were more positive SNB with IRCI: 32.1% versus 55.2%, (P = 0.0432). The incidence of nontherapeutic axillary dissection was similar between the two groups (3.6% for PRCI versus 5.6% for IRCI).
  
  
  CONCLUSIONS
  IRCI for SNB after NAC may be inferior to PRCI.
authors.affiliation: Department of Surgery and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia. Electronic address: hnvu@vcu.edu.
authors.forename: Huan N
authors.initials: HN
authors.lastname: Vu
authors.affiliation: Department of Physical Medicine and Rehabilitation, Wayne State University Detroit Medical Center, Detroit, Michigan.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Shoemaker
authors.affiliation: Department of Dermatology, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Patricia F
authors.initials: PF
authors.lastname: O'Connor
authors.affiliation: Department of Biostatistics and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Wen
authors.initials: W
authors.lastname: Wan
authors.affiliation: Department of Radiology, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Melvin J
authors.initials: MJ
authors.lastname: Fratkin
mesh_terms: D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy; D013671:Technetium Tc 99m Sulfur Colloid / Q000008:administration & dosage*
chemical_list: D013671:Technetium Tc 99m Sulfur Colloid
keywords: Breast cancer; Neoadjuvant chemotherapy; Radiocolloid injection; Sentinel node biopsy