Study Reconfirms Axillary Node Removal Often Too Much
The International Breast Cancer Study Group (IBCSG) 23-01 clinical trial presented at the 2011 San Antonio Breast Cancer Symposium gave further results showing axillary lymph node dissection may be unnecessary in women who have minimal sentinel node involvement.
The 57-month follow-up study, not yet published in a medical journal, showed no significant difference in disease-free and overall survival rates between women who underwent axillary lymph node dissection and those who did not. These findings are consistent with findings from the earlier Z0011 clinical trial.
Background and Reasons for Study
Sentinel lymph node biopsy is a surgery that removes the first node or nodes closest to the original tumor where cancer is most likely to travel. If the sentinel nodes are cancer-free, no further surgery is required. But if cancer is found, most of the underarm lymph nodes may be removed in an axillary lymph node dissection (ALND).
ALND has long been standard treatment when cancer is in the sentinel node. This surgery has several possible side effects including a higher risk for lymphedema, a chronic swelling of the arm, than sentinel biopsy. The goal of lymph node surgery is to prevent local recurrence, or return of the cancer to the same place. This surgery also provides information about the stage of the cancer, which can guide further treatment. It is unclear whether removing the axillary nodes has an impact on recurrence or survival when there is very little cancer in the sentinel node.
This study compared surgery with axillary dissection to surgery without it for treating women whose sentinel lymph nodes showed micrometastases—a small amount of cancer in the sentinel node.
Structure of the Study
Beginning in 2001, researchers randomly assigned 934 women from 27 locations into two groups: axillary dissection and no axillary dissection. All participants all had surgery to remove the primary breast tumor and sentinel nodes.
Most women had lumpectomy, and about 85 percent had cancer in the sentinel nodes. Both groups had similar amounts of radiation, hormonal therapy and chemotherapy after surgery. The average age of participants was 54, and more than half were postmenopausal.
The researchers compared the two groups for disease-free survival and overall survival. Disease-free survival is the time from enrollment until the cancer returned to the same place, or another place. Overall survival is the time from the trial until death from any cause.
Results of the Study
The five-year disease-free survival rate for women who did not undergo axillary dissection was 88.4 percent, compared to 87.3 percent for those who did. The five-year overall survival rate for those who did not have axillary dissection was 98 percent and 97.6 percent for those who did. The slight difference between the two groups shows axillary dissection does not impact survival.
Rates of sensory neuropathy, loss of sensation in the arm or armpit, motor neuropathy, muscle weakness, and lymphedema were also lower for those who did not have axillary dissection.
What This Means for You
The results of this study confirm previous findings that axillary dissection seems to provide no benefit when there is minimal sentinel lymph node involvement. Women who did not have a node dissection had similar survival rates and fewer side effects from surgery. Not having axillary node dissection has the same, and sometimes better, results as having it.
Ask your care team whether foregoing axillary lymph node dissection is a treatment option for you. If the cancer is node-negative or shows minimal sentinel node involvement, this may be a consideration.
Galimberti, V., et. al. Update of International Breast Cancer Study Group Trial 23-01 To Compare Axillary Dissection Versus No Axillary Dissection in Patients with Clinically Node Negative Breast Cancer and Micrometastases in the Sentinel Node. Presented at the 34th Annual San Antonio Breast Cancer Symposium, Abstract S3-1