Sentinel Node biopsy versus Axillary Clearance trial Part 2 (SNAC2)

28 February 2007



SNAC2 aims to determine the long-term safety of sentinel node based management, especially in women with larger or multiple tumours.

Scientific Title

Sentinel Lymph Node Biopsy versus Axillary Clearance In Operable Breast Cancer 2 – (SNAC 2). A multicenter randomised trial of The Royal Australasian College of Surgeons Section of Breast Surgery in collaboration with the National Health and Medical Research Council (NHMRC) Clinical Trials Centre.


When breast cancer spreads it can travel to other parts of the body through the blood and lymph systems. The lymph nodes in the armpit are often the first place where breast cancer spread is detected.  Knowing whether or not these nodes contain cancer is important and used to advise women about prognosis (the risk of recurrence from breast cancer) and additional treatment (for example, endocrine therapy or chemotherapy). Removal of involved nodes may also help prevent local recurrence in the armpit.

Surgical removal and examination by the pathologist is the most reliable way to assess these armpit lymph nodes.  Standard surgery at present (2007 when SNAC2 trial commenced) involves removal of most of the lymph nodes from the lower and upper part of the armpit. This is called axillary clearance or axillary node dissection.  However, this operation is associated with certain risks including infection, pain, shoulder stiffness, upper arm numbness and lymphoedema (arm swelling).  A lesser surgery called sentinel node biopsy which involves removal of the first lymph nodes related to the breast cancer; may provide reliable information on axillary/armpit node status.

The initial Sentinel Node Biopsy versus Axillary Clearance Part 1 (SNAC 1) study, aimed to answer the question: “In women with small breast cancers, does sentinel node biopsy result in reduced side effects from surgery compared to standard axillary clearance?”Part 2 of this research evaluates the use of sentinel node biopsy in women with larger breast cancers or with more than one cancer in the breast, to answer the very important question; “Does sentinel node biopsy result in increased local recurrence or decreased survival, and if so, for which group of women is this the case, and for whom is axillary clearance really necessary?

Enrolment: Closed