Annals of Surgical Oncology

, 15:2728

Is the “10% Rule” Equally Valid for All Subsets of Sentinel-Node-Positive Breast Cancer Patients?

  • Alice Chung
  • Jeanne Yu
  • Michelle Stempel
  • Sujata Patil
  • Hiram Cody
  • Leslie Montgomery
Breast Oncology

DOI: 10.1245/s10434-008-0050-8

Cite this article as:
Chung, A., Yu, J., Stempel, M. et al. Ann Surg Oncol (2008) 15: 2728. doi:10.1245/s10434-008-0050-8

Abstract

Background

In breast cancer, a combination of radioisotope and blue dye mapping maximizes the success and accuracy of sentinel node (SLN) biopsy. When multiple radioactive nodes are present, there is no single definition of isotope success, but the popular “10% rule” dictates removal of all SLN with counts >10% of the most radioactive node. Here we determine how frequently a positive SLN would be missed by the 10% rule.

Methods

Between 9/96 and 12/04, we performed 6,369 successful SLN biopsies using 99mTc sulfur colloid and isosulfan blue dye, removing as SLN all radioactive and/or blue nodes, and taking counts from each node ex vivo. Standard processing of all SLNs with a benign frozen section included hematoxylin and eosin (H&E) staining, serial sectioning, and immunohistochemistry (IHC).

Results

33% of patients (2,130/6,369) had positive SLNs. Of these patients, 1,387/2,130 (65%) had >1 SLN identified. The most radioactive SLN was benign in 29% (398/1,387), and 107/1,387 (8%) had a positive SLN that was neither blue nor the hottest. From this group 1.7% (24/1387) of patients had positive SLN with counts <10% radioactive counts of the hottest node. The 10% rule captured 98.3% of positive nodes in patients with multiple SLNs. No patient characteristics were predictive of failure of the 10% rule.

Conclusion

With combined isotope and blue dye mapping, the 10% rule is a robust guideline and fails to identify only 1.7% (24/1387) of all SLN-positive patients with multiple SLNs. This guideline appears to be equally valid for all subsets of patients.

Keywords

Sentinel lymph node biopsyMapping10% ruleIsotope

Copyright information

© Society of Surgical Oncology 2008

Authors and Affiliations

  • Alice Chung
    • 1
  • Jeanne Yu
    • 1
  • Michelle Stempel
    • 1
  • Sujata Patil
    • 1
  • Hiram Cody
    • 1
  • Leslie Montgomery
    • 1
  1. 1.Department of Surgery, Breast ServiceMemorial Sloan-Kettering Cancer CenterNew YorkUSA