How do we manage the lymph nodes: Axillary dissection vs sentinel node biopsy?
Evaluation of the axillary nodes is currently part of breast cancer staging and can help the clinician determine the need for adjuvant chemotherapy. It also may assist in assessing the need for extending the radiation field beyond the breast to include the regional lymph nodes. Patients with early stage (stage I and II) breast cancer who do not have abnormal palpable lymph nodes or biopsy-proven metastasis to axillary nodes qualify for sentinel lymph node (SLN) biopsy.
Sentinel node biopsy = less morbidity with no loss of accuracy. Compared with axillary lymph node dissection (ALND; removing all the level I and II nodes in the axilla), SLN biopsy has a 98% accuracy and is associated with less morbidity from lymphedema. The procedure involves injecting the breast with 2 tracers: a radioactive isotope, injected into the breast within 24 hours of the operation, and isosulfan blue dye, injected into the breast in the OR at the time of surgery (see illustration). Both tracers travel through the breast lymphatics and concentrate in the first few lymph nodes that drain the breast. The surgery is performed through a separate axillary incision, and the blue and radioactive lymph nodes are individually dissected and removed for pathologic evaluation. On average, 2 to 4 sentinel nodes are removed, including any suspicious palpable nodes. In experienced hands, this procedure has a false-negative rate of less than 5% to 10%.13
Illustration: Kimberly Martens for OBG Management
Subareolar injection of isosulfan blue at the time of sentinal lymph node (SLN) biopsy. The dye, along with a radioactive tracer, concentrates in the lymph nodes that drain the breast. SLN biopsy has 98% accuracy and is associated with less morbidity from lymphedema than axillary lymph node dissection.
Axillary node dissection no longer standard of care. The indication for a completion ALND has changed based on the results of the randomized trial, ACOSOG Z0011.14 In this trial, patients with early stage breast cancer and 1 to 2 positive SLNs who were undergoing breast conservation therapy with radiation and adjuvant systemic therapy were randomly assigned to ALND or no ALND. (The trial did not include patients who were undergoing mastectomy, neoadjuvant chemotherapy, or who had more than 2 metastatic lymph nodes.) The investigators found no difference in overall or disease-free survival or local-regional recurrence between the 2 treatment groups over 9.2 years of follow up.14
Based on this practice-changing trial result, guidelines of the National Comprehensive Cancer Network no longer recommend completion ALND for patients who meet the ACOSOG Z0011 criteria. For patients who do not meet ACOSOG Z0011 criteria, we do intraoperative pathologic lymph node assessment with either frozen section or imprint cytology, and we perform immediate ALND when results are positive.
Indications for SLN biopsy include:
- invasive breast cancer with clinically negative axillary nodes
- ductal carcinoma in situ (DCIS) with microinvasion or extensive enough to require mastectomy
- clinically negative axillary nodes after neoadjuvant chemotherapy.
Contraindications for SLN biopsy include:
- bulky palpable lymphadenopathy
- pregnancy, as the safety of radioactive isotope and blue dye is not well studied; in isotope mapping the radiation dose is small and within safety limits for pregnant patients
- inflammatory breast cancer.
Complications of any axillary surgery may include risk of lymphedema (5% with SLN biopsy and 30% to 40% with ALND).15 Other complications include neuropathy of the affected arm with chronic pain and numbness of the skin.
Positive trends: Improved patient outcomes, specialized clinician training
Management of breast cancer has changed dramatically over the past several decades. More women are surviving breast cancer thanks to improvements in early detection, an individualized treatment approach with less aggressive surgery, and more effective targeted systemic therapies. A multidisciplinary, team-oriented approach with emphasis on minimally invasive biopsy and better cosmetic outcomes has enhanced quality of care.
Complexity in breast disease management has led to the development of formal fellowship training in breast surgical oncology. Studies have demonstrated that patients treated by high-volume breast surgeons are more satisfied with their care and have improved cancer outcomes.16,17 Women should be aware that they have different options for their breast cancer care, and surgeons with advanced specialization in this field may provide optimal results and better quality of care.
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