A breast cancer diagnosis is actually more complex than it may seem. There are many different subtypes of breast cancer. The specific subtypes identified directly impact the treatment plan your oncologist recommends. Let's take a closer look at the various subtypes of breast cancer and how each one influences the recommended treatment approach.

Where Breast Cancer Growth Begins: Ductal vs. Lobular Breast Cancer

Breast cancer primarily originates in two distinct areas of the breast tissue: the ducts and the lobules, leading to two main types of breast cancer—ductal carcinoma and lobular carcinoma. 

Ductal breast cancer begins in the lining of the milk ducts, which are the channels that carry milk from the lobules to the nipple. This type of cancer is often detected early through mammograms because it tends to form calcifications that can be seen on the images. A breast biopsy will finalize whether cancer is present.

On the other hand, lobular carcinoma starts in the lobules, which are the glands responsible for milk production. This type of breast cancer is more challenging to detect on mammograms and may present as a thickened area in the breast rather than a distinct lump. Because of this, it’s more likely to be diagnosed at a later stage. It’s diagnosed most often in post-menopausal women.

How Much Has the Cancer Grown? Invasive vs Non-invasive Breast Cancer

Regardless of where the cancer starts, two main categories indicate how far the cancer has grown at the time it was identified: 

• Non-Invasive Breast Cancer refers to cancerous cells that remain confined to their original location in the breast ducts and have not spread beyond this area. This is also called ductal carcinoma in situ.
• Invasive Breast Cancer (infiltrating) indicates that the cancer has spread to surrounding tissues. Ductal carcinoma is the most common type of invasive breast cancer. Lobular carcinoma and inflammatory breast cancer are also considered invasive types of breast cancer, although they are less common than ductal carcinoma.

Read more in our blog: What’s the Difference Between Invasive and Non-invasive Breast Cancers?

Your oncologist will analyze the results of your breast biopsy and imaging tests to determine whether the cancer is invasive or non-invasive. The biopsy will also indicate if there are other characteristics present that will guide the treatment planning process. 

Subtypes of Breast Cancer That Impact Your Treatment Plan

Hormone Receptor-Positive (HR+) Breast Cancer

Hormone receptor-positive (HR+) breast cancer happens when tumor cells have receptors for estrogen and/or progesterone. This means that the body’s hormones fuel the growth of cancer. Typically, treatment for HR+ breast cancer includes hormone therapy, like Tamoxifen or aromatase inhibitors, which help lower estrogen or progesterone levels to keep cancer cells from growing. 

If your cancer is not affected by hormones, it's classified as hormone-negative breast cancer. In this case, hormone therapy wouldn’t be helpful.

Surgery, radiation therapy, and, in some cases, chemotherapy may also be used for HR+ breast cancer cases. 

HER2-Positive Breast Cancer

HER2 stands for human epidermal growth factor receptor 2. HER2-positive (HER2+) tumor cells have higher levels of this protein, which encourages cancer growth. This type of breast cancer tends to grow and spread faster than others. To treat HER2+ breast cancers, doctors often use chemotherapy and surgery along with targeted therapy drugs that specifically slow the growth of the HER2 protein, which slows the cancer’s growth.

There are different levels of HER2 positivity. You might hear the term HER2-positive or HER2-low. For both HER2 subtypes, the targeted therapy that counteracts the HER2 gene will likely be included in the treatment plan.

Learn more about hormone and HER2-positive breast cancer in our blog.

Triple-Negative Breast Cancer (TNBC)

Triple-negative breast cancer (TNBC) is a less common invasive and aggressive breast cancer. It’s characterized by being estrogen-negative, progesterone-negative, and HER2-negative. Treatment options for TNBC depend on the stage of the cancer and the size of the tumor. Your oncologist may suggest starting with surgery, followed by treatments such as chemotherapy, immunotherapy, or even participation in clinical trials to explore new therapies for triple-negative breast cancer. Learn more about triple-negative breast cancer in our blog.

Inflammatory Breast Cancer (IBC)

Inflammatory breast cancer (IBC) is a rare and fast-growing type of breast cancer, making up about 1-3% of all cases. It can block lymphatic vessels in the skin and breast tissue, leading to symptoms like redness, swelling, and warmth on the breast, sometimes resembling an infection. Unlike other breast cancers, IBC usually doesn’t form a lump, which can make it difficult to catch early. Because it spreads quickly, it’s really important to see a doctor right away if you notice these symptoms. Treatment for IBC usually starts with neoadjuvant chemotherapy, followed by surgery, radiation therapy, and targeted therapy if the cancer is HER2-positive.

Learn more about the molecular subtypes of breast cancer.

Determining the Best Breast Cancer Treatment Options

In addition to the origin of the cancer – ducts or lobules – and whether the cancer is invasive, hormone-positive, or HER2-positive, there are additional factors that influence breast cancer treatment, such as the size and location of the tumor(s), whether the cancer has spread beyond the breast, and your your overall health. For late-stage breast cancer, biomarker testing is also an option to determine if there are additional targeted therapy drugs that could counteract the cancer’s growth. Your oncologist will discuss whether biomarker testing is right for you.

Personalized Breast Cancer Treatment Plans in Colorado

Breast cancer treatments and prognoses vary depending on where the cancer originated, how far it had grown when it was diagnosed, hormone receptors, and HER2 receptors. At Rocky Mountain Breast Specialists, we use a team-based approach to create a tailored treatment strategy based on your unique diagnosis and personal circumstances. Our multidisciplinary team works together to ensure that treatment begins as quickly as possible, leading to the best possible outcomes. We will find the most advanced treatments available today to treat each patient individually.

Expert Cancer Care at Rocky Mountain Breast Specialists

If you or a loved one was diagnosed with breast cancer, our compassionate oncologists and breast surgeons are dedicated to delivering the highest quality care. We encourage you to request an initial consultation or a second opinion to ensure you feel confident in your diagnosis and the recommended treatment plan. We have conveniently located Colorado breast cancer centers in the greater Denver area, Colorado Springs, Boulder, and more.