Less invasive sentinel node surgery is a safe and effective alternative to standard dissection for most breast cancer patients

Sentinel-lymph-node (SLN) surgery is a safe and effective alternative to the more invasive routine axillary-lymph-node dissection (ALND), with equivalent survival rates in breast cancer patients with clinically negative lymph nodes. These findings from the largest randomised surgical trial of breast cancer to date, published in The Lancet Oncology, should benefit the majority of breast cancer patients.

ALND removes all the lymph nodes in the underarm region. The technique is used to maximise breast cancer survival and regional control, and to determine if cancer has spread beyond the breast. But the procedure is associated with unpleasant side-effects including nerve damage and reduced arm and shoulder function. SLN surgery involves the removal of only the sentinel nodes, the first set of lymph nodes under the arm that cancer spreads to. The technique was designed to preserve tissue and minimise side-effects, but still achieve the same cancer control.

The National Surgical Adjuvant Breast and Bowel Project (NSABP) B-32 trial was set up to establish whether SLN surgery can achieve the same survival and regional control as ALND, but with fewer side effects.

5611 women with SLN-negative breast cancer were recruited from 80 centres in the USA and Canada and randomly assigned to SLN surgery plus ALND (group 1) or SLN surgery alone (group 2). Patients were assessed at 4–6 month intervals for overall survival, disease-free survival, and regional control. The trial was designed to detect a small 2% difference in survival to ensure that any reduction in morbidity was not at the expense of reduced survival.

After a mean follow-up of 8 years, there were no significant differences in overall survival, disease-free survival, or regional control between the two groups.

Functional arm deficits, sensory problems and lymphoedema were all decreased in the SLN alone group. Acute adverse side-effects were limited to allergic reactions in 46 patients, mostly related to the blue dye used in the SLN biopsy procedure.

The authors say: "The results from B-32 show that in the SLN-negative population, any survival advantage of full ALND is fully mitigated by simply removing the SLNs."

They conclude: "SLN surgery alone with no further ALND is an appropriate, safe, and effective therapy for breast cancer patients with clinically negative lymph nodes...SLN surgery represents the next major step in reducing the extent of surgical procedures to treat breast cancer."

In a Comment, John Benson from the Cambridge University Teaching Hospitals Trust, Cambridge, UK, says that this seminal paper: "Vindicates contemporary practice of SLN biopsy and provides support for a reduction in extent of axillary surgery for most patients with breast cancer."

Source: Lancet Oncology