Less Invasive Breast Cancer Therapy Found Equally Effective

National Surgical Adjuvant Breast and Bowel Project (NSABP; Pittsburgh, PA, USA) randomized 5,611 women with invasive breast cancer in a controlled phase 3 trial at 80 centers in Canada and the United States between May 1, 1999, and Feb 29, 2004. The women were assigned to either SLN resection plus axillary-lymph-node dissection (ALND), or to SLN resection alone, with ALND performed only if the SLNs were found positive. The primary endpoint was overall survival. Outcome analyses were done in patients who were assessed as having pathologically negative sentinel nodes, and for whom follow-up data were available. All deaths, irrespective of cause, were included.

The results showed that 3,989 of the women had pathologically negative SLN. Of these, 309 deaths were reported in the SLN-negative patients with follow-up information: 140 of 1,975 patients in the SLN plus ALND group, and 169 of 2,011 in SLN alone group. Overall survival in both groups yielded an unadjusted hazard ratio (HR) of 1.20; 8-year estimates for overall survival were 91.8% in the SLN plus ALND group, and 90.3% in the SLN alone group. Treatment comparisons for disease-free survival yielded an unadjusted HR of 1.05, and 8-year estimates for disease-free survival were 82.4% in the first group and 81.5% in the second; 14 women in the SLN group had cancer return, compared to 8 of those who had the more aggressive surgery. The study was published early online on September 21, 2010, in the Lancet Oncology.

"Overall survival, disease-free survival, and regional control were statistically equivalent between groups,” concluded lead author professor David Krag, M.D., of the University of Vermont (Burlington, USA). "When the SLN is negative, SLN surgery alone with no further ALND is an appropriate, safe, and effective therapy for breast cancer patients with clinically negative lymph nodes.”

The sentinel lymph node is the hypothetical first lymph node or group of nodes reached by metastasizing cancer cells from a primary tumor. The concept of the sentinel lymph node is important because of the advent of the sentinel lymph node biopsy technique, also known as a sentinel node procedure, used in the staging of certain types of cancer to see if they have spread to any lymph nodes, since lymph node metastasis is one of the most important prognostic signs. It can also guide the surgeon to the appropriate therapy.

Related Links:
U.S. National Surgical Adjuvant Breast and Bowel Project
University of Vermont