title: Is routine intraoperative frozen-section examination of sentinel lymph nodes in breast cancer worthwhile?
abstract: BACKGROUND
  Routine intraoperative frozen section (FS) of sentinel lymph nodes (SLN) can detect metastatic disease, allowing immediate axillary dissection and avoiding the need for reoperation. Routine FS is also costly, increases operative time, and is subject to false-negative results. We examined the benefit of routine intraoperative FS among the first 1000 patients at Memorial Sloan Kettering Cancer Center who had SLN biopsy for breast cancer.
  
  
  METHODS
  We performed SLN biopsy with intraoperative FS in 890 consecutive breast cancer patients, none of whom had a back-up axillary dissection planned in advance. Serial sections and immunohistochemical staining for cytokeratins were performed on all SLN that proved negative on FS. The sensitivity of FS was determined as a function of (1) tumor size and (2) volume of metastatic disease in the SLN, and the benefit of FS was defined as the avoidance of a reoperative axillary dissection.
  
  
  RESULTS
  The sensitivity of FS ranged from 40% for patients with Tla to 76% for patients with T2 cancers. The volume of SLN metastasis was highly correlated with tumor size, and FS was far more effective in detecting macrometastatic disease (sensitivity 92%) than micrometastases (sensitivity 17%). The benefit of FS in avoiding reoperative axillary dissection ranged from 4% for Tla (6 of 143) to 38% for T2 (45 of 119) cancers.
  
  
  CONCLUSIONS
  In breast cancer patients having SLN biopsy, the failure of routine intraoperative FS is largely the failure to detect micrometastatic disease. The benefit of routine intraoperative FS increases with tumor size. Routine FS may not be indicated in patients with the smallest invasive cancers.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Weiser
authors.forename: L L
authors.initials: LL
authors.lastname: Montgomery
authors.forename: B
authors.initials: B
authors.lastname: Susnik
authors.forename: L K
authors.initials: LK
authors.lastname: Tan
authors.forename: P I
authors.initials: PI
authors.lastname: Borgen
authors.forename: H S
authors.initials: HS
authors.lastname: Cody
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D005629:Frozen Sections / Q000592:standards*; D006801:Humans; D007150:Immunohistochemistry; D007432:Intraoperative Period; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000592:standards*