Breast Cancer Types & How It Spreads to Lymph Nodes

When people think of breast cancer, they might picture a lump in the breast, but breast cancer is more than that. Hearing the words “breast cancer” can make your head spin. It’s one of the most emotional times in anyone’s life, and the sheer amount of information you have to absorb like tests, treatment options, side effects, it can feel like too much to handle all at once. One thing I wish I’d known early on is that not all breast cancers are the same, and knowing your cancer type helps shape the best treatment plan for you. Cancer is a disease that can spread or metastasize to other parts of the body so let’s talk about how doctors treat the three main types of breast cancer which are hormone receptor-positive, HER2-positive, and triple-negative breast cancer; and what each one means for your care.

Category Types of Breast Cancer

Here’s a quick look at the main types of breast cancer and how they’re different:

Hormone Receptor-Positive (ER+ or PR+): If your doctor tells you that your cancer is hormone receptor-positive, it means the cancer cells grow in response to hormones like estrogen or progesterone. This is actually good news in some ways, because it opens up more treatment options. Doctors often recommend hormone therapy, like tamoxifen or aromatase inhibitors, which work by blocking the hormones that help the cancer grow. Along with hormone therapy, you might also have surgery to remove the tumor or the whole breast (called a mastectomy), radiation therapy to target any remaining cancer cells, and sometimes chemotherapy if the cancer is larger or has spread to lymph nodes. It’s all about giving you the best possible chance to beat the cancer and keep it from coming back.

HER2-Positive: If your cancer is HER2-positive, it means the cancer cells make too much of a protein called HER2, which can help the cancer grow faster. The good news is that there are powerful targeted therapies that specifically attack these HER2 proteins, like Herceptin (trastuzumab) and others; which can slow or even stop the cancer’s growth. In addition to targeted therapy, you’ll likely have surgery, chemotherapy, and sometimes radiation therapy to make sure all the cancer is treated and doesn’t come back. These treatments work together to give you the best chance of recovery.

Triple-Negative Breast Cancer (TNBC): Triple-negative breast cancer sounds intimidating, and it’s true that it can be more aggressive than other types. Unlike hormone receptor-positive or HER2-positive cancers, triple-negative cancer doesn’t have those markers that let doctors target it with hormone therapy or HER2 drugs. That means the main treatments are chemotherapy, surgery, and radiation therapy. Doctors may also consider newer immunotherapy drugs, especially if the cancer has spread or come back. Triple-negative breast cancer can be scary, but treatments are improving all the time, and many people do very well with the right care and follow-up. (This is the one I had)

But wait, there's more:

Subtypes of Breast Cancer

Inflammatory Breast Cancer (IBC)

A rare but aggressive type that causes the breast to look red and swollen.

Can be any receptor status (ER+, HER2+, or triple-negative).

Lobular Carcinoma

Starts in the milk-producing glands (lobules).

Can be hormone receptor-positive or triple-negative.

Ductal Carcinoma

Starts in the milk ducts. Can also be hormone receptor-positive, HER2-positive, or triple-negative. (This is the one I had)

Paget’s Disease of the Nipple

A rare type that starts in the ducts and spreads to the skin of the nipple. Most often, it’s linked to ductal carcinoma in situ (DCIS) or invasive ductal carcinoma (IDC) which means it can be hormone receptor-positive (ER+/PR+) or HER2-positive, but it’s less commonly triple-negative.

Medullary, Mucinous, or Tubular Breast Cancers

Special histological types that can behave differently and may have different growth patterns and treatment approaches. These cancers are most often hormone receptor-positive (ER+/PR+), but they can also be HER2-positive or triple-negative, though less commonly.

Do All Breast Cancers Spread the Same Way?

All breast cancers (whether hormone receptor-positive, HER2-positive, or triple-negative) generally spread first through the lymphatic system (via lymph vessels) to nearby lymph nodes especially the axillary nodes under the arm. After lymph node spread, they can enter the bloodstream, where they can travel to distant organs like the bones, lungs, liver, and brain.

What are the differences?

Some subtypes, like triple-negative breast cancer, can spread more aggressively and may show up in unusual places (like the brain) earlier.

HER2-positive cancers can sometimes have a higher risk of spreading quickly but also respond well to targeted treatments.

Hormone receptor-positive cancers often spread more slowly and are more likely to go to the bones than to the brain.

How Does Breast Cancer Spread to Lymph Nodes?

Step 1: The Cancer Starts in the Breast

The cancer begins as a small group of cells in the breast tissue. These cells grow and form a tumor.

What will you feel: You might feel a lump or notice a change in your breast during a self-exam, or it might be found during a routine mammogram.

Step 2: Cancer Cells Break Away

As the tumor grows, some cells can break off and start looking for a new home.

What will you feel: This happens silently in your body; you can’t feel these cells moving.

Step 3: Cancer Travels Through the Lymphatic System

The cancer cells enter tiny tubes called lymphatic vessels, which carry fluid throughout the body.

What will you feel: Nothing here because this is happening automatically inside your body on a cellular level.

Step 4: Cancer Reaches the Lymph Nodes

The cancer cells are carried to the nearest lymph nodes, often under the arm (axillary nodes) first. From there, they can spread to supraclavicular or internal mammary nodes.

What will you feel: If you notice swelling, tenderness, or lumps in these areas, let your doctor know. They might relate it to an infection or an illness like the flu or covid.

Step 5: Diagnosing You

Doctors use imagine tests and sentinel lymph node biopsies to see if the cancer has spread. This helps determine the stage and the best treatment plan.

What's next? Ask your doctor what stage your cancer is, and what treatment is recommended. They might need to go through an extensive process to stage you to ensure accurate diagnoses and treatment.

Something To Think About:

Every breast cancer journey is unique, and the treatments your doctor recommends will depend on the type of cancer, its stage, and your overall health. It’s normal to feel overwhelmed at first, but you’re not alone. Talk to your doctor, ask questions, and lean on your support system. Early detection matters and knowing how the cancer spreads can help you understand why certain treatments are recommended. You can take control of your health and make decisions that feel right for you

Other Important Information: All breast cancers typically spread through the lymphatic system first, then through the bloodstream. The molecular subtype (ER/PR, HER2, TNBC) affects how fast and where it’s likely to spread. No matter the subtype, the initial route. through the lymphatic system and then the blood, is generally the same but the speed, pattern, and aggressiveness of spread can differ depending on the type.

*Sources:

American Cancer Society. “Understanding a Breast Cancer Diagnosis.” American Cancer Society, 2023. Web. https://www.cancer.org/cancer/types/breast-cancer/understanding-a-breast-cancer-diagnosis.html.

American Cancer Society. “Triple-Negative Breast Cancer.” American Cancer Society, 2023. Web. https://www.cancer.org/cancer/types/breast-cancer/about/types-of-breast-cancer/triple-negative.html.

Mayo Clinic. “Breast Cancer: Types.” Mayo Clinic, 2023. Web. https://www.mayoclinic.org/diseases-conditions/breast-cancer/in-depth/breast-cancer/art-20045654.

Macmillan Cancer Support. “Breast Cancer and the Lymphatic System.” Macmillan Cancer Support, 2023. Web. https://www.macmillan.org.uk/cancer-information-and-support/breast-cancer/breast-cancer-and-the-lymphatic-system.

Living Beyond Breast Cancer. “Where Breast Cancer Spreads.” Living Beyond Breast Cancer, 2023. Web. https://www.lbbc.org/about-breast-cancer/types-breast-cancer/metastatic-breast-cancer/where-breast-cancer-spreads.