Updated September 04, 2013.

When I woke up from my breast biopsy, my husband told me it was indeed cancer. I began to weep, thinking I would have to undergo surgery, chemotherapy, and updating my will (just in case). But more news was to come, and so much to learn.

At first we thought it was well-contained (in-situ), not invasive breast cancer. But we also needed to know the tumor size, grade, hormone status, HER2 status, and whether it had spread beyond my breast.

So I started down the road for more tests, including testing of my lymph nodes. I had no idea why those tiny things were so important.

But now I know, and to help you understand how your lymph node status affects your treatment decisions, I looked up the experts in UpToDate -- a trusted electronic reference used by many of the oncologists who treat breast cancer patients.

Here's what the experts say, and below that, you'll see my notes about lymph node status and how that may affect your treatment decisions.

The importance of the axillary lymph nodes: A discussion on diagnosis and staging workup from UpToDate

"One of the first sites of breast cancer spread is to the lymph nodes located in the armpit (axilla). These nodes (referred to as axillary lymph nodes) can become enlarged and can sometimes be felt during a breast examination. However, even if the lymph nodes are enlarged, the only way to determine if they truly contain cancer is to examine a sample of the tissue under the microscope.
The presence or absence of lymph node involvement is one of the most important factors in determining the long-term outcome of the cancer (prognosis), and it often guides decisions about treatment."

Why Are Lymph Nodes Important?
Breast cancer starts out with just a few cells, which group together in your breast tissue. They may be camping out in the system where breast milk is produced: your ducts and lobes. As these cells grow and divide, they may also invade nearby tissue. A growing tumor may shed a cell, or a clump of cells. This independent cancer cell can use your blood or lymph system like a network of highways so it can travel throughout your body. Your lymph system works with your circulating blood to provide nutrients to all your cells, as well as remove cellular waste products. The lymph nodes are the "pit stops" on this highway system, where lymphatic fluid is filtered, mixed with immune cells (lymphocytes), and passed back into your circulating lymph fluid. So, if a loose cancer cell makes it to your lymph nodes, it's also possible that the cancer could get sent along to other parts of your body. If you get an infection, your lymph nodes near the affected area may swell because they have collected germs. And if you develop breast cancer, the lymph nodes in your armpit (axillary lymph nodes) is the most common place that cancer cells would lodge, causing those nodes to swell.

Why Do I Need a Lymph Node Biopsy?
Breast tissue itself contains some lymph nodes, which process lymphatic fluid and pass it along. Breast tumors tend to drain towards your axilla, or underarm area. Checking the underarm lymph node location should be part of a clinical breast exam, as well as your breast self-exam. Swollen lymph nodes might be evidence that cancer has spread beyond your breast, but the only way to know for sure is to have them removed and tested. There are two procedures for lymph node biopsy: sentinel node biopsy and axillary lymph node dissection (removal of all the nodes). The pathology report about these lymph nodes gives you your lymph node status.

How Does My Lymph Node Status Affect My Treatment Options?
Your lymph nodes may be clear of cancer, and if so, your lymph node status is negative, and rated N0. If you have a small tumor and clear nodes, it is less likely that you will need to have chemotherapy. That is not a guarantee, however, because your doctor will also consider your tumor grade, tumor size, hormone receptor status and how effective surgery can be for you. If your lymph nodes do contain cancer, they are considered positive, or involved, and are rated N1, N2, or N3 depending on the number affected and the location. Having involved lymph nodes suggests that the cancer has demonstrated an ability to spread beyond your breast, and you will be advised to have adjuvant systemic therapy, such as chemotherapy, after surgery to kill any additional cancer cells that persist in your body.

What Does All This Mean For My Prognosis?
Prognosis, also called outlook, is one way a doctor talks about how the odds for survival stack up for you, after you've completed treatment. Remember, having just one cancer cell in your body is one too many. Treatment is designed to kill off as many, if not all, of your cancer cells as possible. If you had clear lymph nodes and a small, low-grade tumor, your prognosis after treatment is pretty good. On the other end of the spectrum, if you had 10 or more involved lymph nodes and a larger tumor, your treatment will likely be more aggressive, and your outlook will be harder to determine, until after you've finished all treatments. No matter where your diagnosis fits on that scale, please know that survival rates are improving, treatments are becoming more efficient and effective, and even metastatic breast cancer can be managed like a chronic disease.

Want to learn more? See UpToDate's topic, "Patient information: Breast cancer guide to diagnosis and treatment: The importance of the axillary lymph nodes," for additional in-depth, current and unbiased medical information on breast cancer, including expert physician recommendations.

<sub>Source:

Diane MF Savarese, Leah K Moynihan. Patient information: Breast cancer guide to diagnosis and treatment: The importance of the axillary lymph nodes.UpToDate. Accessed: January 2009.</sub>

Lymph Node Rating

Lymph Node Rating	Meaning of Rating
N0	Negative or clear - contains no cancer and no micrometastasis
N1, 2, 3: Positive (involved) lymph nodes
N1	Cancer is found in 1-3 lymph nodes under the arm or lymph nodes within the breast
N2	Cancer is found in 4-9 lymph nodes under the arm or lymph nodes within the breast
N3	Cancer is found in 10 or more lymph nodes under the arm, or has spread under or over the collarbone. It may have been found in the underarm nodes as well as lymph nodes within the breast