Axillary Radiotherapy and SNL Surgery Show Comparable Outcomes

Patients with early-stage breast cancer had similar recurrence and survival rates for both axillary lymph node radiotherapy (RT) and dissection, according to a new study.

Researchers at the Netherlands Cancer Institute (NKI; Amsterdam), the European Organisation for Research and Treatment of Cancer (EORTC; Brussels, Belgium), and other institutions conducted a study in 4,806 patients with early-stage, clinically node-negative breast cancer, of whom 1,425 went on to have a positive sentinel lymph node (SLN) biopsy. Of these, 744 were randomly assigned to the axillary lymph node dissection group, and 681 to the axillary RT group. After 10 years, 1.82% of those assigned to axillary RT had axillary recurrence, compared with 0.93% of those assigned to dissection.

In addition, distant metastasis-free survival was 78.2% among those assigned to axillary RT and 81.7% among those assigned to axillary lymph node dissection; overall survival in the two arms was 81.4% percent and 84.6%, respectively. A significantly greater proportion of patients assigned to axillary RT went on to develop a second primary cancer (11%) than did patients assigned to axillary lymph node dissection (7.7%). The difference was mainly due to a higher incidence of contralateral breast cancer in the patients treated with axillary RT. The study was presented at the annual San Antonio Breast Cancer Symposium, held during December 2018 in San Antonio (TX, USA).

“Our new 10-year data show that axillary radiotherapy and axillary lymph node dissection provide excellent and comparable overall survival, distant-metastasis-free survival, and locoregional control,” said lead author and study presenter radiation oncologist Mila Donker, MD, PhD, of NKI. “We believe that axillary radiotherapy should be considered a good option for patients who have a positive sentinel lymph node biopsy, instead of complete surgical clearance of the axillary lymph nodes.”

“Traditionally, those patients who had cancer detected in a SLN biopsy underwent axillary lymph node dissection, which is an effective but invasive surgical procedure that is associated with adverse side effects such as lymphedema and difficulties moving the arm,” said senior author surgical oncologist Emiel Rutgers, MD, PhD. “There may be some patients who do not need axillary treatment, even if they have a positive SLN biopsy. Moving forward, we need to better tailor treatment for each individual patient. Some will still need axillary treatment, and our data indicate that axillary radiotherapy is a good option here.”

Finding metastatic cancer cells during breast cancer surgery requires first identifying the position of the SNLs, which have a diameter of just a few millimeters, and then excising them for hisotpathology. If the cancer has not yet metastasized to an SLN, axillary lymph node excision can be omitted, thus preventing subsequent lymphedema and maintaining the patient's quality of life after surgery.

Related Links:
Netherlands Cancer Institute
European Organisation for Research and Treatment of Cancer