Sentinel lymph node biopsy often is done before or during breast cancer surgery to help figure out if the cancer has spread to lymph nodes in the nearby underarm (axillary) area. If cancer cells are found in the sentinel node, both the sentinel node and other axillary lymph nodes are usually removed, either during the breast cancer surgery or later with another surgery, depending on when the sentinel node biopsy results are available.
A small study found that doing an ultrasound of the underarm lymph nodes before breast cancer surgery accurately identified the cancer's spread to the lymph nodes in nearly 30% of women diagnosed with breast cancer that had spread to those nodes. Knowing that the cancer had spread to the underarm lymph nodes before breast cancer surgery meant that the women had axillary lymph node dissection instead of sentinel node biopsy, avoiding a second surgery after sentinel node biopsy. The results were presented at the 2009 ASCO Breast Cancer Symposium.
The 274 women in the study were diagnosed with early-stage breast cancer and were having a lumpectomy. Several days before surgery, all of the women had an ultrasound of their underarm lymph nodes on the same side as the breast cancer to see if the cancer had spread to those lymph nodes. If the ultrasound showed a suspicious area, the women had a fine needle biopsy of the lymph nodes. If the fine needle biopsy showed cancer in the lymph nodes, the women had axillary biopsy during breast cancer surgery. If the fine needle biopsy showed no cancer or the ultrasound had no suspicious areas, the women had sentinel node biopsy during breast cancer surgery.
Overall, 57 (20.8%) of the 274 women had cancer in the axillary lymph nodes.
- 40 women (70.2%) had the cancer in the axillary lymph nodes identified by sentinel node biopsy; the ultrasound did NOT identify the spread in these women.
- 17 women (29.8%) had the cancer in the axillary nodes identified by the ultrasound and confirmed by fine needle biopsy; a sentinel node biopsy wasn't needed and so wasn't done in these women.
It's important to note that ultrasound didn't suggest that cancer had spread to the lymph nodes when it actually had not. In other words, underarm ultrasound didn't result in any false positives.
In this study, cancer in the axillary lymph nodes was mainly diagnosed by sentinel node biopsy, NOT underarm ultrasound. While ultrasound helped some women, sentinel node biopsy was a critical diagnostic step for most of the women. If you've been diagnosed with early-stage breast cancer and working on a treatment plan with your doctor, you might want to ask your doctor about the results of this study. The results suggest an underarm ultrasound done before sentinel node biopsy and breast cancer surgery might accurately identify the cancer's spread to the axillary lymph nodes, allowing you to have axillary node biopsy as part of your breast cancer surgery without having sentinel node biopsy. If the ultrasound shows no spread, it's likely that you'll have sentinel node biopsy.
You can learn more about lymph node surgery in the Breastcancer.org Lymph Node Removal pages.
Editor's note: To make sure that women have the appropriate lymph node surgery, the American Society for Clinical Oncology released guidelines on sentinel lymph node biopsy for people diagnosed with early-stage breast cancer. The guidelines say sentinel lymph node biopsy SHOULD be offered under these circumstances:
- breast cancer in which there is more than one tumor, all of which have formed separately from one another (doctors call these multicentric tumors); these types of breast cancers are rare
- DCIS treated with mastectomy
- women who have previously had breast cancer surgery or axillary lymph node surgery
- women who have been treated before with chemotherapy or another systemic treatment (treatment before surgery is called neoadjuvant treatment)
Sentinel node biopsy SHOULD NOT be offered under these circumstances:
- the cancer is 5 cm or larger or locally advanced (the cancer has spread extensively in the breast or to the nearby lymph nodes)
- the cancer is inflammatory breast cancer
- DCIS treated with lumpectomy
- the woman is pregnant
The guidelines also say:
- Women with negative sentinel node biopsies shouldn’t have axillary node surgery.
- Women with one or two positive sentinel nodes who plan to have lumpectomy plus radiation also don’t need axillary node surgery.
- Women who have one or more positive sentinel nodes and plan to have mastectomy with no radiation should be offered axillary node surgery.