|The following article features coverage from the San Antonio Breast Cancer Symposium (SABCS) 2017 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.|
A growing evidence base supports a “less is more” approach to axillary node staging and management, according to Tari A. King, MD, FACS, of the Dana-Farber Cancer Institute in Boston, Massachusetts, during a plenary presentation at the 2017 San Antonio Breast Cancer Symposium.1
Communicating this to patients can, however, be challenging. “In daily clinical practice, the challenge lies in clear communication of the myriad of options and the interplay between tumor biology, systemic therapy, and surgical decision-making,” Dr King said.
Sentinel lymph node (SLN) biopsy has been widely used since the 1990s and led to a decline in axillary node dissection (ALND) and the serious and painful comorbidities ALND can cause, such as lymphedema.
Based on findings from several randomized clinical trials, observation, rather than ALND, is now a viable option for women with only 1 or 2 cancer-positive SLNs who are undergoing breast conservation therapy (BCT), Dr King said. Axillary node radiotherapy is an alternative to ALND for women undergoing mastectomy. Additional personalization of axillary management is afforded by the availability of neoadjuvant therapy for women with high-risk clinically node-negative (cN0) breast cancer — and even in some node-positive (cN1) cases, Dr King said.
The evidence base for SLN biopsy among women with cN1 axillary nodes continues to evolve, she added. One unresolved question is whether axillary node tumor cells can be eradicated with neoadjuvant chemotherapy. “There is concern that residual disease will be resistant to therapy,” Dr King noted. There are not many data available on locoregional recurrence in this setting. Memorial Sloan Kettering Cancer Center’s experience with SLN after neoadjuvant therapy for patients with stage II-III disease with positive SLNs is that 85% convert from cN1 to cN0.
The early ACOSOG Z1071, SN-FNAC, and SENTINA trials showed that false-negative rates depend on the number of SLNs removed, but these trials cannot speak to axillary risk recurrence for SLN biopsy-only staging following neoadjuvant chemotherapy, Dr King said. Patients in those early trials all underwent ALND.
Treatment planning should include consideration of SLN performance after neoadjuvant therapy, primary tumor molecular subtype, and the anticipated type of surgery. Neoadjuvant therapy is associated with high rates of nodal pathological complete response (pCR) in women with HER2-positive or triple-negative breast cancer, reducing the likelihood that ALND will be needed even in patients with cN1 disease.
For women with cN1 disease, neoadjuvant treatment might allow axillary down-staging. Patient selection is crucial, Dr King added. Patients with low-to-intermediate grade and node-positive hormone receptor–positive breast cancer can undergo adjuvant endocrine therapy without chemotherapy.
The evidence base for axillary node management after neoadjuvant endocrine therapy is, however, scant. Ongoing clinical trials should clarify optimal axilla management (SLN biopsy vs axillary observation) and treatment de-escalation options for patients with normal axillary ultrasound findings after neoadjuvant chemotherapy, Dr King said. Findings from those studies should help determine if regional nodal radiotherapy can be avoided in these patients, for example.
Read more of Cancer Therapy Advisor‘s coverage of the San Antonio Breast Cancer Symposium (SABCS) 2017 meeting by visiting the conference page.
- King, T. Individualizing management of the axillary nodes. Oral presentation at: 2017 San Antonio Breast Cancer Symposium; December 5-9, 2017; San Antonio, TX.