Breast Cancer Treatment with SLND Alone Shows Similar Survival Rates to ALND

Among women with invasive breast cancer and sentinel node metastasis, the use of sentinel lymph node dissection (SLND) alone was shown to be noninferior in terms of survival compared with the standard treatment, axillary lymph node dissection (ALND), according to results of a recent study [JAMA. 2011;305(6):569-575]. ALND is often performed in conjunction with breast cancer surgery to identify nodal metastases and maintain regional control, but whether and/or to what extent it helps maintain local disease control is not definitively known. ALND also carries risks of complications including seroma, infection, and lymphedema. SLND was developed as a means to accurately stage axillary nodes with fewer complications, and has become accepted management for patients with sentinel lymph nodes free of cancer. ALND has remained the standard for patients whose sentinel lymph nodes are confirmed to be metastatic. The necessity of ALND, however, has been called into question as breast cancer treatment has evolved and the involvement of lymph node metastases has decreased. Armando E. Giuliano, MD, of the John Wayne Cancer Institute at St. John’s Health Center, Santa Monica, California, and his colleagues conducted a multicenter, randomized phase 3 study known as Z0011 to examine the impact of ALND on overall survival among 891 patients with breast cancer. Enrollment began in 1999 and ended in 2004. All women had sentinel lymph node metastasis and were treated via lumpectomy, adjuvant systemic therapy, and tangential field radiation therapy. The primary end point of the study was overall survival. Secondary end points included disease-free survival. All patients underwent SLND and were stratified according to age, estrogen receptor status, and tumor size. Women were then randomized to receive either ALND (n=445) or no axillary-specific treatment (n=446). History and physical examinations were done every 6 months for the first 3 years and yearly afterward. The women were assessed for disease recurrence and were also required to have annual mammograms. The researchers used Kaplan-Meier survival curves compared by log-rank test to estimate overall survival and Cox regression to determine unadjusted and adjusted hazard ratios (HRs) for overall survival. Results showed that after a median follow-up of 6.3 years there were a total of 94 deaths: 42 in the SLND-only group and 52 in the ALND group. The researchers found 5-year overall survival rates to be 92.5% (95% confidence interval [CI], 90%-95.1%) for the SLND-only group and 91.8% (95% CI, 89.1%-94.5%) in the ALND group. The adjusted (for adjuvant therapy and age) HR for overall survival was 0.87 (90% CI, 0.62-1.23) for the SLND-alone group compared with the ALND group. The unadjusted HR was 0.79. Disease-free survival was also found to be similar between groups; the 5-year rate was shown to be 83.9% (95% CI, 80.2%-87.9%) for the SLND-alone group and 82.2% (95% CI, 78.3%-86.3%) for the ALND group (P=.14). Adjusted and unadjusted HRs for the SLND-only group compared with the ALND group were 0.88 (95% CI, 0.62-1.25) and 0.82 (95% CI, 0.58-1.17), respectively. Results further showed 5-year rates of local recurrence to be 1.6% (95% CI, 0.7%-3.3%) for the SLND-alone group and 3.1% (95% CI, 1.7%-5.2%) for the ALND group (P=.11). At 5 years, locoregional recurrence-free survival was 96.7% (95% CI, 94.7%-98.6%) for the SLND-only group versus 95.7% (95% CI, 93.6%-97.9%) for the ALND group (P=.28). Complications such as wound infections, axillary seromas, and paresthesias occurred more frequently among women who received ALND compared with the SLND-only group (70% vs 25%; P<.001). The researchers acknowledged limitations of the study included a failure to reach target accrual and a possible randomization imbalance that favored the SLND group.