The American Society of Clinical Oncology (ASCO) published its first guideline for sentinel lymph node biopsy in 2005.1 Since that time, many new randomized and cohort studies have been published investigating the indications and outcomes of the procedure. The updated 2014 guideline, recently published in Journal of Clinical Oncology and reviewed in this issue of The ASCO Post, considers new evidence from recent studies including 13 cohort studies and 9 randomized trials.2 It is clear from these studies that more patients are suitable candidates for sentinel lymph node biopsy without completion of axillary lymph node dissection.
Associated Morbidity
The importance of adequate use of this procedure cannot be overemphasized. Axillary dissection is associated with significant transient and permanent morbidity. Further, axillary dissection results in significant time away from routines of daily life and can lead to permanent symptomatic lymphedema, numbness, decreased shoulder mobility, and pain.
While sentinel lymph node biopsy can result in the same complications, the prevalence of these sequelae is much lower after sentinel lymph node biopsy than after axillary lymph node dissection. This is clear from the randomized studies in which complications of the two procedures can be directly compared. Every study shows lower complication rates for sentinel lymph node biopsy than axillary lymph node dissection and high axillary staging accuracy for sentinel lymph node biopsy alone.
The prospective randomized trials show no increased recurrence rates or mortality when sentinel lymph node biopsy alone is performed with omission of axillary lymph node dissection for patients whose sentinel lymph nodes are tumor-free. These studies support the important recommendation that patients whose sentinel lymph nodes are free of metastasis not undergo axillary lymph node dissection.
Key New Recommendation
A major change from the 2005 guideline is the additional recommendation that axillary lymph node dissection can be omitted for some sentinel lymph node–positive patients. The impetus for this recommendation was a careful evaluation of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial, which randomly assigned clinically node-negative patients who had clinical T1 or T2 tumors and only one or two positive sentinel lymph nodes to either completion of axillary lymph node dissection or sentinel lymph node biopsy only.3 All patients underwent whole-breast irradiation with opposing tangential fields. Prone irradiation, accelerated partial-breast irradiation, and third-field nodal irradiation were prohibited. Nearly all patients in both arms received adjuvant chemotherapy or endocrine therapy.
At a median follow-up of 6.3 years, 0.9% of the sentinel lymph node biopsy–only group developed axillary recurrence compared to 0.5% of the group receiving sentinel lymph node biopsy followed by axillary lymph node dissection. There was no significant difference in overall survival or disease-free survival between the two groups. This trial illustrated that completion of axillary lymph node dissection may be omitted in a select group of patients with sentinel lymph node metastases and led to this significant change in the 2014 ASCO guideline.
In the opinion of the ASCO expert panel, axillary lymph node dissection can be avoided in patients with one or two nodes involved with metastatic cancer but only when conventionally fractionated whole-breast irradiation is planned and adjuvant systemic therapy is given. This recommendation applies to patients with either sentinel lymph node micrometastases or macrometastases.
This single important change will affect most women with early breast cancer and nodal metastasis since most women with tumor-involved sentinel nodes have only one or two involved nodes. The recommendation does not apply to patients treated with accelerated partial-breast irradiation or irradiation in the prone position. Those whose axillary nodal disease is documented by fine-needle aspiration may still undergo sentinel lymph node biopsy if the abnormal lymph node is removed. The panel still advises completion of axillary lymph node dissection for women with early-stage breast cancer undergoing mastectomy.
Unconsidered Study
Results of the randomized AMAROS trial conducted by the European Organisation for Research and Treatment of Cancer (EORTC) were presented at the 2013 ASCO Annual Meeting but were not fully published and, therefore, were not considered for the guideline update.4 Clinicians should be aware of this study, since it offers an additional option for sentinel lymph node–positive patients, even those treated with mastectomy.
The AMAROS trial randomly assigned patients with a tumor-involved sentinel lymph node to axillary irradiation or axillary lymph node dissection. The 5-year axillary recurrence rates were very low in both the axillary irradiation and axillary lymph node dissection groups. The disease-free survival rates were similar in the two groups, and there was no statistical difference in overall survival. However, there were fewer complications in the axillary irradiation patients, including a lower frequency of lymphedema (P < .0001). The decreased rate of lymphedema after nodal irradiation was still seen at 1, 3, and 5 years. The study will likely prove to be an important one, but determination of its full impact awaits careful evaluation of published results.
Additional Change
An additional change from the prior guidelines relates to patients treated with neoadjuvant systemic therapy, who may now be offered sentinel lymph node biopsy before or after their treatment. Women with large or locally advanced breast cancer or inflammatory breast cancer should not receive sentinel lymph node biopsy. Most patients with ductal carcinoma in situ undergoing breast-conserving surgery should not undergo sentinel lymph node biopsy, nor should pregnant patients.
The new ASCO guideline extends sentinel lymph node biopsy to more patients and confirms its clinical utility. The guideline suggests that sentinel lymph node biopsy is appropriate for most patients with early operable breast cancer. The ASCO committee encourages patients to speak with their multidisciplinary care team in order to fully understand their options and determine whether sentinel lymph node biopsy is appropriate for them. ■
Dr. Giuliano is Executive Vice Chair, Surgery, Cedars-Sinai Medical Center, Los Angeles. He was Co-Chair of the Update Committee on sentinel node biopsy with Gary H. Lyman, MD, MPH, FASCO.
Disclosure: Dr. Giuliano reported no potential conflicts of interest.
References
1. Lyman GH, Giuliano AE, Somerfield, MR, et al: American Society of Clinical Oncology guideline
recommendations for sentinel lymph node biopsy in early-stage breast cancer.
J Clin Oncol 23:7703-7720, 2005.
2. Lyman GH, Temin S, Edge SB, et al: Sentinel lymph node biopsy for patients with early-stage breast cancer: American Society of Clinical Oncology clinical practice guideline update.
J Clin Oncol 32:1365-1383, 2014.
3. Giuliano AE, Hunt KK, Ballman KV, et al: Axillary dissection vs no axillary dissection in women with invasive breast cancer and sentinel node metastasis—a randomized clinical trial. JAMA 305:569-575, 2011.
4. Rutgers EJ, Donker M, Straver ME, et al: Radiotherapy or surgery of the axilla after a positive sentinel node in breast cancer patients: Final analysis of the EORTC AMAROS trial (10981/22023). 2013 ASCO Annual Meeting. Abstract LBA1001. Presented June 3, 2013.
