Research summary
February 2007
Sentinel node biopsy as accurate as routine axillary clearance but with fewer side effects
Summary
A clinical trial involving 1088 women in Australia and New Zealand has shown the benefits of sentinel node biopsy in determining whether breast cancer cells have spread beyond the breast to regional nodes.
The trial is being run by the Royal Australasian College of Surgeons in collaboration with the NHMRC Clinical Trials Centre at the University of Sydney. The trial is called the Royal Australasian College of Surgeons trial of Sentinel Node Biopsy versus Axillary Clearance for early invasive breast cancer, or the RACS SNAC Trial.
The trial compared the techniques of sentinel node biopsy and routine axillary clearance. After 12 months follow-up the results showed that sentinel node biopsy is as accurate as axillary clearance in determining if the cancer has spread in women with tumours less than 3cm. Women who underwent sentinel node biopsy also had fewer problems with arm swelling, movement, sensation and other aspects of quality of life than the women who underwent routine axillary clearance.
Follow-up will continue for 10 years to determine the long-term effects of sentinel node biopsy.
A second trial, known as SNAC2, has recently opened to recruitment. It will examine whether sentinel node biopsy is preferable to routine axillary clearance for women with breast tumours that are large or multiple.
National Breast Cancer Centre comment
Routine axillary clearance is a surgical technique currently used to determine whether there is any evidence of breast cancer cells spreading beyond the breast, which impacts on treatment recommendations. It involves the removal of most of the lymph nodes or glands in the armpit of the affected side and a pathologist looking for any cancer cells which may have spread from the breast cancer. The removal of these nodes is commonly associated with side effects that impact on quality of life, such as swelling of the arm (lymphoedema) and restriction of movement.
Sentinel node biopsy is a technique which involves the removal of only the first one or more nodes to which the lymphatics from the breast drain – called the sentinel node(s).
There are two ways to find the sentinel node; either method or preferably a combination of the two can be used. In one technique, a radioactive substance is injected around the breast cancer or the nipple. Scans are used before and during surgery to find out which lymph node the radioactive substance has travelled to. Another technique is to inject blue dye around the breast cancer or the nipple just before surgery. The surgeon can see and remove the sentinel node because it turns blue when the dye travels to it.
If cancer is found in the sentinel node, the surgeon will remove more lymph nodes (axillary clearance). However, in about 70 per cent of women, the cancer has not spread and removal of further nodes is not required.
This research is significant news for women with breast cancer. The findings indicate that for tumours less than 3cm, sentinel node biopsy is an alternative technique to routine axillary clearance in determining the spread of disease. However, further follow-up of the trial will determine whether the technique has any impact on overall recurrence and survival.
The National Breast Cancer Centre is currently developing recommendations on the use of sentinel node biopsy as part of a review of its Clinical practice guidelines for the management of early breast cancer. The recommendations will be released later in the year.