There are many types of breast cancer

The Many Forms of Breast Cancer

A cancer diagnosis is never good news for a patient. It can be scary, unknown, and confusing. As health care professionals, it’s important we educate ourselves about common health concerns and fears, so we can educate and advocate for our patients when they get such a life-changing diagnosis. 

October is well known to be Breast Cancer Awareness month, and in recognition of the many patients with this diagnosis and the professionals working to care and cure, here’s what you need to know about the many types of breast cancer.

What are the Types of Breast Cancer?

Cancer is a complex disease. Breast cancer might seem straightforward enough — it’s a cancer that originates in cells in a patient’s breast and can happen to someone of any gender. 

But breast cancer comes in many forms, and what type it is determines a patient’s prognosis and the treatments that are available and effective.

In order to successfully diagnose the type of breast cancer affecting a patient, there are several key questions health care professionals investigate. 

Where Did It Start?

Health care professionals determine the type of breast cancer based on the cells in the breast that it originates from. The cancer could start in any of the following cells of the breast:

  • Milk ducts
  • Milk-producing lobules
  • Connective tissue.

It’s rarer for breast cancer to start within the connective tissue of the breast and much more common for it to originate in the milk ducts or lobules.

Where Is It Now?

The scary aspect of cancer is how quickly it can spread to the rest of the body. During diagnosis and throughout the course of treatment and in post-cancer follow-ups, health care professionals want to know if the cancer cells are in situ or if they’ve spread and become invasive.

In situ breast cancer means the cancer has stayed in the cells where it’s started. For example, if the cancer cells originate from the milk ducts, and so far the cancer has stayed in the milk ducts, it’s in situ. One of the technical terms for this type of breast cancer is ductal carcinoma in situ (DCIS).

Once the cancer has metastasized into the surrounding breast tissue or even throughout the rest of the body, then it becomes known as invasive breast cancer. DCIS can start off in situ but can become invasive if treatment isn’t started quickly.

About 80% of breast cancers begin in the ducts and are invasive. The second most common type of diagnosed breast cancer begins in the lobules and is also invasive. 

What Does It Look Like?

One method of diagnosing the type of breast cancer a patient has is taking a look at the cancer cells through a microscope. Certain types of breast cancer are diagnosed down to a subtype that’s made obvious through microscopic analysis. 

Different subtypes will have different cell appearances. These subtypes include:

  • Colloid (mucinous)
  • Medullary
  • Micropapillary
  • Papillary
  • Tubular

Although these subtypes are different from invasive ductal and invasive lobular breast cancers, each type of breast cancer has a unique look under the microscope. 

How the cancer cells look under a microscope also determines the cancer’s grade. Health care professionals grade breast cancer on a scale of 1 to 3 in order to determine how aggressive the cancer is multiplying and spreading. 

The most aggressive cancers are graded 3, and the cancer’s grade is based on how different the cancer cells look compared to normal breast cells.

What Is Its Genetics?

Genetics has a major role in many types of cancers, and that especially includes breast cancer. As the field of genetics advances, so too does our ability to further classify diseases. 

It might sound like a lot of extra work, but knowing the details of a cancer subtype down to its genes not only helps researchers look at new possible treatments, but it helps health care professionals narrow down current treatments to give patients the best chance at recovery.

After taking a biopsy of the cancer tissue from the breast, professionals can determine which of the main subtypes a breast cancer is:

  • Luminal A
  • Luminal B
  • Triple-negative/basal-like
  • HER2-enriched
  • Normal-like

The genes of these subtypes affect how and whether or not the cancer cells respond to the hormones estrogen and progesterone. Knowing these details is a great help in determining the types of treatments and whether or not a patient has the option of using something like hormone therapy.

A cancer diagnosis can be complex to understand for patients and even for many health care professionals. By taking the time to learn and understand the different types of breast cancer, we can help patients work through such a diagnosis and the treatments that follow.