SNAC2: A randomised trial of extending sentinel node based management to women with larger or multifocal breast cancers

Lead researcher

Dr Neil Wetzig (QLD), A/Professor Grantley Gill (SA), A/Professor Owen Ung (NSW), A/Professor John Collins (VIC), Dr David Oliver (WA)

Royal Melbourne Hospital

Years funded

Over 13,000 ANZ women are diagnosed with breast cancer each year. Most need surgery to remove the cancer and determine if it has spread to glands in the armpit (axillary lymph nodes). Knowing whether the cancer has spread to the axillary lymph nodes helps determine prognosis and plan treatment.

Surgical removal is the most reliable way to assess the axillary lymph nodes.SNAC2 compares two operations for assessing cancer spread to the lymph nodes in women with early breast cancer:

  1. axillary clearance and
  2. sentinel node biopsy.

Axillary clearance involves removal of most lymph nodes in the armpit. In sentinel node biopsy only a few lymph nodes most closely related to the breast cancer are removed. Axillary clearance is the current standard operation. However, it is associated with risks including infection, pain, stiffness, numbness and lymphoedema (arm swelling).

Lymphoedema may occur in 5-50% of women treated for breast cancer and can cause major suffering and disability. In many women their breast cancer has not spread to the lymph nodes, and axillary clearance is unnecessary. Recent studies suggest sentinel node biopsy may provide as much information as axillary clearance. Scans and dye are used to help locate the sentinel nodes. Minimising the amount of surgery to the armpit should reduce the side effects. However, the long term safety and effectiveness of removing only a few nodes is unknown.

SNAC2 extends the work begun in SNAC1, which recruited 1,088 women over 4 years. SNAC1 will determine if sentinel node biopsy causes less arm problems than axillary clearance. SNAC2 is needed to determine whether the smaller operation gives cure rates as good as axillary clearance. If it does, then it will become standard practice. SNAC2 will better inform women and surgeons about the pros and cons of sentinel node biopsy in a wider range of circumstances.


$30,000 per annum