Longer Life Foundation Final Report Project Title: Minimally Invasive Staging of the Axilla in Breast Cancer

Sentinel lymph node biopsy (SLNB) has emerged as a less invasive alternative to axillary lymph node dissection (ALND) in the treatment of breast cancer. However, SLNB has a number of limitations, and we believe that alternative strategies for staging of the axilla should be explored. The hypothesis of this proposal was that the combination of preoperative high-resolution axillary ultrasound (AUS), fine needle aspiration biopsy (FNAB), and molecular analysis using real-time reverse transcription-polymerase chain reaction (RT-PCR) represents a viable, minimally invasive alternative to SLNB. A prospective cohort study was used to assess the diagnostic accuracy of molecular analysis of AUS-FNAB specimens. Eighty female patients with pathologically confirmed, clinically node-negative invasive breast cancer who were considered to be candidates for SLNB were eligible for enrollment. The primary endpoint of this study was to determine the feasibility of AUS-FNAB and real-time RT-PCR to predict the pathologic status of the axilla in a proof-ofprinciple study. Lay Summary The most important prognostic factor for a patient with breast cancer is the absence or presence of metastasis to the axillary lymph nodes. Survival correlates directly with the number of positive lymph nodes. Historically, all women with breast cancer underwent surgery to their breast (mastectomy or lumpectomy) plus removal of all of the axillary (i.e., armpit) lymph nodes on the side of their breast cancer. While this technique is very effective in determining the number of lymph nodes involved with cancer, it also subjects the patient to significant morbidity, including bleeding, infection, nerve injury, and permanent swelling of the arm (lymphedema). Currently, this procedure is still performed in women who have enlarged, suspicious lymph nodes by physical exam (approximately 10-20% of all patients) and the complication rates are reported to be 10-30%. More recently, a less invasive technology has emerged to examine the axillary lymph nodes in women who do not have enlarged lymph nodes on physical exam (approximately 8090% of all patients). This is termed a sentinel lymph node biopsy and has been rigorously tested and proved effective in patients with breast cancer. The sentinel lymph node concept supports the notion that breast cancer cells spread in an orderly fashion from the primary tumor in the breast to a few lymph nodes in the axilla (i.e., the “sentinel” lymph nodes). By injecting blue dye and radioactive particles near the tumor, we can follow the lymph vessels to the