A new prospective study has reported that early stage breast cancer patients with positive sentinel lymph nodes do not experience reduced local recurrence, increased disease-free survival, or increased overall survival as a result of axillary lymph node dissection. Sentinel lymph node dissection (in which the first lymph node or nodes to which cancer is likely to spread from the primary tumor are removed for biopsy) accurately serves to identify lymph node metastasis of early stage breast cancer, but it is unclear whether further lymph node removal affects survival. The current report summarizes the results of the American College of Surgeons Oncology Group Z0011 trial, which was conducted at 115 sites which enrolled patients from 1999 to 2004.
Study participants were women with early stage invasive breast cancer, no palpable enlargement of lymph nodes, and having one or two positive sentinel lymph nodes (i.e., containing metastases). All study participants had a lumpectomy and whole-breast irradiation. Women found to have positive sentinel lymph nodes were assigned randomly either to undergo axillary lymph node dissection (surgery to remove lymph nodes in the armpit) or not. Clinical and tumor characteristics were similar between the two groups. Systemic therapy such as chemotherapy was given at the discretion of the treating oncologist. A total of 445 patients were randomized to receive axillary lymph node dissection and 446 were randomized to sentinel lymph node biopsy alone. The median number of nodes removed was 17 in the axillary lymph node dissection group and two in the sentinel lymph node biopsy alone group.
The rate of wound infections, axillary fluid buildup (seromas), and prickly, tingling sensations was higher among the women in axillary lymph node dissection group (70%) than among the women in the sentinel lymph node dissection alone group (25%). As of a median follow-up period of 6.3 years, 52 of the axillary lymph node dissection group had died and 42 of the sentinel lymph node biopsy only group had died. Five year overall survival was 91.8% in women who received axillary lymph node dissection compared to 92.5% in women who had sentinel lymph node dissection alone. Five year disease-free survival was 82.2% among women who received axillary lymph node dissection, which was very similar to the 83.9% found among women who had sentinel lymph node dissection alone. The authors conclude that axillary lymph node dissection may no longer be justified for certain breast cancer patients.