Older women diagnosed with DCIS see no long-term benefits from having sentinel lymph node biopsy to see if the cancer has spread beyond the breast to the lymph nodes, according to a study by Yale University researchers.
The study was published in the December 2019 issue of the journal JNCI Cancer Spectrum. Read “Long-Term Outcomes of Sentinel Lymph Node Biopsy for Ductal Carcinoma in Situ.”
DCIS stands for ductal carcinoma in situ. It is also called stage 0 breast cancer. “Ductal” in the name means the cancer started in milk ducts. DCIS is non-invasive cancer, which means it hasn’t spread beyond the milk duct into any normal surrounding breast tissue. DCIS isn’t life-threatening, but a DCIS diagnosis increases the risk of developing an invasive breast cancer in the future. The American Cancer Society estimates that about 48,000 cases of DCIS will be diagnosed in the United States in 2019.
About sentinel lymph node biopsy
When a person is diagnosed with invasive breast cancer, the surgeon usually removes some of the underarm lymph nodes to figure out if the cancer has spread beyond the breast. This is called lymph node surgery, lymph node biopsy, or lymph node dissection.
Lymph is a clear fluid that travels through your body's arteries, circulates through your tissues to cleanse them and keep them firm, and then drains away through the lymphatic system. Lymph nodes are the filters along the lymphatic system. Their job is to filter out and trap bacteria, viruses, cancer cells, and other unwanted substances and to make sure they are safely eliminated from the body.
There are two types of lymph node surgery for breast cancer:
- sentinel lymph node biopsy, where only the one or two lymph nodes closest to the cancer are removed
- axillary lymph node biopsy, where between five and 30 or more lymph nodes under the arm are removed
The type of lymph node surgery a person has depends on several factors, including the size and other characteristics of the cancer, as well as whether any lymph nodes look enlarged or cancerous.
While sentinel lymph node biopsy is less likely to cause lymphedema than axillary lymph node biopsy, lymphedema is still a risk with any lymph node surgery.
Lymphedema happens when too much lymph collects in any area of the body. If lymphedema develops in people who’ve been treated for breast cancer, it usually occurs in the arm and hand, but sometimes it affects the breast, underarm, chest, trunk, and/or back.
Breast cancer surgery — especially when several lymph nodes are removed — and radiation can cut off or damage some of the nodes and vessels through which lymph moves. Over time, the flow of lymph can overwhelm the remaining pathways, resulting in a backup of fluid into the body’s tissues.
About this study
People diagnosed with DCIS almost always have surgery to remove the cancer, usually a lumpectomy rather than a mastectomy. In many cases a sentinel lymph node biopsy is done at the same time as the lumpectomy. But because DCIS is non-invasive, experts do not recommend that people diagnosed with DCIS have lymph nodes removed.
So why are so many sentinel lymph node biopsies done during DCIS surgery?
“Proponents of sentinel lymph node biopsy cite concerns that … microinvasive disease within the DCIS may not be detected via other methods,” said lead author Shi-Yi Wang, M.D., associate professor of epidemiology at Yale, in a statement. “Also, the sentinel lymph node biopsy is included in the Centers for Medicare & Medicaid merit-based incentive payment system for invasive breast cancer. This might create a financial incentive for providers to perform these biopsies even for non-invasive conditions.”
Yang and his team did this study to see if sentinel lymph node biopsy helped improve outcomes after DCIS surgery.
The researchers looked at the records of 12,776 U.S. women age 67 to 94 who were diagnosed with DCIS and had lumpectomy. The women were diagnosed with DCIS between 2001 and 2013. Overall, 1,992 of the women — about 16% — also had sentinel lymph node biopsy.
Women who had sentinel lymph node biopsy tended to:
- be younger
- be white
- be diagnosed more recently
- have higher-grade DCIS
- have larger DCIS tumors
To compare outcomes, the researchers matched the 1,992 women who had sentinel lymph node biopsy with 3,965 women diagnosed with DCIS who had lumpectomy but did not have sentinel lymph node biopsy. The women were matched on the bases of:
- cancer grade
- cancer size
- hormone receptor status
- year of diagnosis
- geographic region
The women were followed for about 6 years after the initial lumpectomy.
The researchers found that adding sentinel lymph node biopsy to lumpectomy surgery for DCIS did not:
- reduce the risk of dying from breast cancer
- lower the risk of being diagnosed with invasive breast cancer
- reduce the number of additional cancer treatments a woman had
The researchers pointed out that because only women age 67 to 94 were included in the study, the results couldn’t be applied to younger women. Wang also said that more research is needed to figure out if sentinel lymph node biopsies offer benefits to people diagnosed with high-grade DCIS.
What this means for you
If you’re a woman age 67 or older diagnosed with DCIS who will be having lumpectomy to remove the cancer and your doctor recommends you also have sentinel lymph node biopsy, you may want to bring up this study.
As the researchers who did this study noted, it’s not clear if sentinel lymph node biopsy would offer benefits to an older woman diagnosed with high-grade DCIS.
So it makes sense to ask your doctor about the grade of the DCIS with which you’ve been diagnosed. It also makes sense to ask about the benefits and risks of sentinel lymph node biopsy, including the risk of lymphedema.
Together, you and your doctor can make the best decision for you.
For more information, visit the Breastcancer.org pages on Sentinel Lymph Node Dissection.
If you're an older woman diagnosed with DCIS and would like to talk with others with a similar diagnosis, join the Breastcancer.org Discussion Board forum Older Than 60 Years Old With Breast Cancer.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser