Removal of lymph nodes in the area surrounding the breast and in the armpit — a strategy designed to prevent the spread of cancer cells to the rest of the body — appears unnecessary for many women with early-stage breast cancer, according to an accumulated body of research.

The most recent research, presented at the 2023 San Antonio Breast Cancer Symposium (SABCS), found that women with breast cancer who had less extensive lymph node removal surgery were less likely to recur or die from the disease. Removing fewer nodes did mean the women were less prone to lymphedema, a painful accumulation of lymph fluid, after surgery, though. The finding was based on an analysis of 29 clinical trials that included, in all, a little more than 20,000 women with early breast cancer.

A definitive study, published in JAMA, followed women with early-stage breast cancer who were treated with a lumpectomy followed by radiation or other therapy to kill remaining cancer cells. Half of the women in the study had only a few lymph nodes removed (sentinel lymph node biopsy) from under the underarm, while the other half had a large number of lymph nodes removed, a procedure known as axillary lymph node dissection. After 10 years of follow-up, both groups had similar rates of disease recurrence and survival.

The study confirms the results of an earlier study published in JAMA.

What to Do About Lymph Nodes in the Armpit

Early-stage breast cancer is generally defined as disease that has not spread beyond the breast or the axillary lymph nodes. The majority of breast cancer patients in the United States are diagnosed with early-stage cancer.

Research done almost 30 years ago revealed that breast cancer often first spreads to nearby lymph nodes in the axilla, or underarm, called the sentinel nodes. Taking out and examining one to three sentinel nodes — called a sentinel lymph node biopsy — can help physicians assess the spread of cancer.

“The sentinel node is the first lymph node to which cancer will spread, if it spreads,” says Armando Giuliano, MD, regional medical director of the breast oncology program at Cedars-Sinai Medical Center in Los Angeles, who worked on much of the early research on sentinel node biopsy. “We’ve proven that if the sentinel node is negative (no cancer), 99 percent of the time the cancer has not spread elsewhere in the body.”

What if a Sentinel Node Is Positive?

But the question of whether surgeons need to remove axillary nodes beyond the sentinel ones when a sentinel node is positive for cancer remains open. In the past, doctors generally took out the axillary nodes as a precaution. “We expected that there would be other positive nodes, and you wouldn’t want to leave those behind,” says Dr. Giuliano.

While many doctors embraced the findings of the early research, others felt it was too short and had too few patients to draw firm conclusions. The study that followed, which followed the patients for 10 years, confirmed the original findings.

Removing Lymph Nodes and Lymphedema Risk

The question matters.

Axillary lymph node dissection, which typically involves removal of at least 10 nodes, can have troubling consequences. Lymph nodes carry fluid, called lymph, through regions of the body to help fight infection and remove toxins. When a large group of the tiny, round nodes is surgically removed, lymph fluid may be unable to flow freely. The buildup of fluid is called lymphedema.

“Some women get terrible arm swelling from lymphedema,” Giuliano says. “You can have shoulder problems, such as a limited range of motion, numbness, and pain that can be chronic and persist long term. These problems are very difficult to manage.”

It may worry some women to leave the lymph nodes intact when cancer is found in one or two sentinel nodes. But, Giuliano points out, most patients with early-stage breast cancer also have radiation therapy, which kills cancer cells in the lymph nodes. Chemotherapy, hormone therapy, and targeted therapy — medication prescribed to some women based on the type of breast cancer they have — also destroys cancer in lymph nodes.

The study findings apply only to women with early-stage breast cancer who have lumpectomy and additional treatment, such as radiation and chemotherapy. More research is needed on whether other types of breast cancer patients can perhaps avoid axillary lymph node removal.

“The main question now concerns how to manage the axillary lymph nodes if a breast cancer patient has had chemotherapy before the operation,” Giuliano says. “What is the effect of chemotherapy on nodal involvement?”

For now, women with early-stage breast cancer who choose lumpectomy followed by additional therapy should discuss the necessity of axillary lymph node removal with their doctors prior to surgery, he says. If axillary node removal is absolutely recommended, “Get a second opinion,” he says.