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High Resolution Breast PET in Evaluating Axillary Lymph Node Status for Pre-Surgical Planning: Initial Clinical Experience
James R. Kinney, MD; Sue Griffin, RN; Nancy Weinand (ARRT, N) Weidong Luo, PhD
INTRODUCTION
Clinical evaluation of the axilla is an area of increasing interest in managing breast cancer. Axillary lymph node status is a critical prognostic indicator. Physical exam has proven to be inadequate, with some studies demonstrating error rates as high as 41% and false positive rates as high as 53% [1,2]. Tis-sue diagnosis of axillary metastases influences cancer therapeutics and is key to breast cancer staging. Until the recent past staging was done with a complete level I and II lymph node dissection for all pa-tients diagnosed with invasive disease.
Lymphatic mapping enabled the less invasive intraoperative technique of sentinel node biopsy which has led to reduction in patient complications of paresthesia and lymphedema [3]. Current standard of care is trending toward optimizing preoperative techniques that can inform the surgical and treatment approach. One such technique is axillary evaluation with ultrasonography frequently combined with fine needle aspiration or core needle biopsy.
However, studies have shown discrepant results in the sensitivity, specificity and predictive value of this method [4,5,6,7]. Breast MRI is another modality that can be used, however it is time consuming, expensive and often not readily available. A meta analysis of the literature on this method shows promise but remains inconclusive [8]. One recent study found abnormal nodes on US, MRI, or mammogram in clinically node-negative patients are not reliable indicators of the need for ALND [9]. Metabolic information provided by high resolution breast PET could play a major role in guiding the preoperative investigation, to in-clude decisions regarding neoadjuvant chemotherapy and the use of sentinel lymph node biopsy (SLNB) and/or axillary lymph node dissection (ALND).
Current methods of assessing axillary lymph nodes like clinical exam, ultrasound and MRI, are all based on morphology.