The National Breast and Ovarian Cancer Centre (NBOCC) is the national authority and source of evidence-based information on breast and ovarian cancer in Australia. Guidelines for treatment are developed at the NBOCC using the best available research data from around the world.
In 2008, the NBOCC released guidelines for the use of sentinel node biopsy (SNB) in Australia. SNB is a surgical procedure which removes the first lymph node or nodes to which cancer cells are most likely to spread, called the sentinel node. Research has found that SNB results in less arm damage, shorter hospital stays and improved quality of life compared with the traditional surgery to remove nodes in the armpit, which is called axillary dissection.
After the NBOCC guidelines were released, information regarding clinical practice was gathered from:
- National Breast Cancer Audit
- New South Wales Central Cancer Registry
- Victorian Cancer Registry
- Medicare Benefits Schedule
- Some Australian pathology laboratories
This study showed that the guidelines were generally being applied for women with early breast cancer across the country.
Recommendation 1: In women with early (operable) breast cancer, SNB should be offered as an alternative to axillary dissection for women with one tumour up to 3 cm in diameter and with lymph nodes that did not show cancer.
This study found that for women in Australia with one tumour up to 3 cm:
- between 78 and 83% had an SNB
- SNB was less likely if they were being treated outside a major city, were a public patient, or as the size of the tumour increased.
Recommendation 2: After SNB: axillary dissection is recommended if cancer cells are found in the sentinel node(s) (node positive); monitoring of the nodes in the armpit (axilla) by a clinician is recommended if no cancer cells are found in the sentinel node(s) (node negative).
The study found that:
- between 74% and 77% of patients who were node positive at the time of SNB went on to receive axillary dissection
- 6% of node-negative patients went on to have axillary dissection.
Recommendation 3: Where possible, the sentinel node(s) should be located using a combination of:
- lymphatic mapping (a tiny amount of radioactive material is injected around the tumour to map the way lymph drains from a tumour to its corresponding lymph nodes)
- preoperative lymphoscintigraphy (viewing the path of the radioactive substance through imaging equipment to identify the sentinel nodes before surgery)
- intraoperative use of gamma probe (a hand-held device for locating the radioactive material, and therefore the sentinel nodes, during surgery)
- blue dye (surgeon injects blue dye around the tumour, the lymph nodes stained with dye are sentinel nodes)
The study showed that in 90% of SNBs both preoperative lymphoscintigraphy and blue dye were used to locate sentinel nodes. This figure was similar across regions and states, with the exception of Queensland, where only 63% used both approaches.
Recommendation 4: It is recommended that cancer is detected through detailed histological assessment (examination of a tissue sample taken from the patient, under a microscope, by a pathologist) of the sentinel node. This should include:
- serial sectioning (cutting the specimen into thin sections and mounting every section onto slides for examination, rather than examining one section only)
- immunohistochemistry (a type of stain used on the samples to make cancer cells more visible)
A survey was sent to pathology labs in Australia. Although less than half responded to the survey, the information gathered showed that:
- the majority (96%) submit the entire sentinel node for histological assessment
- 83% routinely use multiple levels of sectioning for staining
- 86% routinely use immunohistochemistry.
Since the survey was conducted, results from the ACOSOG Z0010 trial have questioned the routine use of immunohistochemistry for examination of sentinel lymph nodes.