Breast cancer doesn’t always stay in your breast. Sometimes, cancer cells move to lymph nodes, which changes several things about your diagnosis, staging, and treatment.
Understanding how lymph nodes fit into the bigger picture can help you make sense of the risk of your cancer coming back (recurrence), its outlook, and why your doctors suggest certain treatments. Here’s what you need to know.
Lymph Nodes and How They Relate to Breast Cancer
Lymph nodes are small, bean-shaped parts of the body’s lymphatic system. It’s like your circulatory system, but instead of being a passageway for blood, it’s a superhighway for fluid in your body called lymph.
Lymph moves white blood cells around your body to help fight infection. It also transports waste products, bacteria, and damaged cells from your body’s tissues so that they can be removed or destroyed.
Lymph nodes are checkpoints along this lymph superhighway. They filter the waste and bacteria from the lymph and add more white blood cells to it. They’re located in your:
- Neck (cervical lymph nodes)
- Chest (thoracic and mediastinal lymph nodes)
- Armpit (axillary lymph nodes)
- Abdomen (para-aortic, peri-aortic, and mesenteric lymph nodes)
- Groin (inguinal lymph nodes)
In some breast cancers, cancer cells break off the original tumor and travel to other places in the body. Typically, the first place they go is the closest lymph nodes, which would be the axillary lymph nodes in your armpit. From there, they can continue spreading to other lymph nodes and organs.
Breast cancer that has spread to lymph nodes has a worse outlook and a higher chance of coming back than breast cancer that stays in the breast. The more lymph nodes you have with breast cancer cells in them, called “positive lymph nodes,” the higher the chance your breast cancer will return.
Factors That Affect Recurrence Risk
Breast cancer cells in your lymph nodes are one of the biggest risk factors for recurrence, but there’s more to consider than just their presence. When figuring out your prognosis, treatment, and recurrence risk, doctors look at several things:
Number of positive lymph nodes. The more lymph nodes that contain cancer, the higher the risk of recurrence. It also matters how many cancer cells your doctor sees in your lymph nodes, says Christina Annunziata, MD, PhD, an oncologist and senior vice president of extramural discovery science at the American Cancer Society.
“If we find something microscopically, then that means there’s much less of a chance it will come back,” Annunziata says. “And if you can feel them, that’s what we call ‘clinically present.’ That means there are more cells than just one or two. That means a lot of cells have gotten out.”
Location of lymph nodes. Your doctor will check your axillary lymph nodes in your armpit first, as they’re closest. But they’ll also look farther.
“The next few places it would go is up above your collarbone, which is called supraclavicular, and then into the lymph nodes along your internal jugular vein,” Annunziata says. “We call that a local spread. It can also spread into the body, into the deep lymph nodes in the center of your chest, right where your lung bronchus is.”
Your doctor won’t be able to feel these deeper lymph nodes. You’d need to get imaging done to see them. If your cancer cells have spread even farther, they may have reached your liver or bones. The further away the positive lymph nodes are from your breast, the higher your chance of recurrence.
Tumor size. The larger your breast cancer tumor, the more likely it is to spread. Your doctor will consider the tumor size, whether your lymph nodes are involved, and how many are involved when staging your cancer and estimating the risk of recurrence.
Tumor biology. Not all breast cancers are the same. Your doctor will find out your cancer’s hormone receptor status (HR-positive or HR-negative) and HER2 status to figure out the most effective treatment for you.
How Positive Lymph Node Number Changes Your Prognosis
The number of lymph nodes involved in your breast cancer is one of the most important pieces of information your doctor uses to estimate how your cancer will advance and the chance of it coming back. For example, the more lymph nodes your doctor removes during treatment, the worse your prognosis.
Although survival rates depend on several different factors, studies estimate the following:
Zero positive lymph nodes. Typically, your outlook is excellent if you have negative lymph nodes, and the recurrence risk is very low. “If there were no lymph nodes involved, there’s more than a 90% chance that the cancer is not going to come back,” Annunziata says.
One to three lymph nodes involved. Modern treatments make the prognosis much better at this stage than it used to be. Your risk of recurrence is higher than if zero lymph nodes were involved. After five years, an average of 80% of people in this category have not had their cancer return.
Four or more lymph nodes involved. Your risk of recurrence goes up a good bit when you have so many lymph nodes involved. Only 54% of people remain disease-free after five years. Your doctor is likely to treat your cancer more aggressively because the likelihood that cancer cells have spread even farther is higher.
But it’s important to remember that even with lymph node involvement, the treatments available today have dramatically improved breast cancer outcomes.
How Lymph Node Involvement Affects Treatment
Lymph node status not only predicts recurrence risk but also shapes the decisions your doctor makes about treatment.
If cancer is just in your breast, you may only need surgery and radiation in your armpit or collarbone area, just to be sure to get any stray cells. But if your tumor is on the larger side, you may need more preventative measures.
“If it has gotten to a larger size, then we might be making an assumption that some microscopic cells have gone even further,” Annunziata says. “You want to maybe treat with a bigger radiation field and/or treat with systemic chemotherapy.”
Chemotherapy
Doctors recommend chemotherapy more commonly for positive lymph nodes because it treats cancer cells that may have already spread through the bloodstream. They call this adjuvant therapy if chemotherapy is given after surgery and neoadjuvant therapy if chemotherapy is done before surgery.
“You want to give chemotherapy so that it goes everywhere in your body and it picks up individual little breast cancer cells that might have gone somewhere else outside of that immediate lymph node,” Annunziata says. “The farther it is, the more chemotherapy you’re going to do.”
Hormone therapy
If your breast cancer is hormone-receptor-positive, your doctor can use estrogen-blocking treatments, such as tamoxifen or aromatase inhibitors, after your primary treatment to lower your recurrence risk for many years. This cuts off the fuel source that makes the cancer cells grow.
Targeted therapy
If your cancer is HER2-positive, your doctor can use targeted drugs such as trastuzumab (Herceptin) to lower your risk of recurrence. They typically do this whether you have positive lymph nodes or not.
Managing Recurrence Anxiety
It’s normal to worry about recurrence, especially if your lymph nodes were involved in your breast cancer. But every breast cancer journey is unique, and treatments have improved a lot.
“We have a much better handle on how to treat various types of breast cancer,” Annunziata says. “We have a lot of new treatments that can keep the cancer away, and then they can keep the cancer controlled if it does come back.”
It’s really important to attend your doctor’s visits once active treatment is done.
“An action item for people is really to remain vigilant on following up on their treatment plan,” Annunziata says. “Come in for your exam and do your scans.”
