Breast Cancer 101 – Part I – What Is Breast Cancer, Types and How to Identify?

Breast cancer is one of the most complicated cancers anyone can have. Breast cancer inflicts both men and women, but it is more common in women. If you have been diagnosed with breast cancer, don’t panic because breast cancer treatments today are better than ever especially if the cancer is discovered early.

This article will describe the different types of breast cancer and the imaging process associated with a breast cancer diagnosis which can help you understand this type of cancer.

What is Breast Cancer?

According to the American Cancer Society (ACS), breast cancer begins when cells in the breast grow out of control. Breast cancer starts from different parts of the breast. Cancer cells that start in the ducts are called ductal cancer while cancer cells that begin in the glands that make breast milk are lobular cancer.

Additionally, there are a small number of cancers that begin in other tissues of the breast and are known as sarcomas and lymphomas. The majority of breast cancer begins in the ducts that carry milk to the nipple known as ductal cancer. Not all breast cancer form lumps and can be detected through a mammogram.


Types of Breast Cancer

There are mainly two types of breast cancer categorized as invasive and non-invasive. Invasive also called infiltrating breast cancer occurs when cancer cells spread to other parts of the body through the blood stream and lymph system.

The ACS describes the two invasive breast cancers as invasive or infiltrating ductal carcinoma (IDC) and invasive or infiltrating lobular carcinoma (ILC) and describes the two non-invasive breast cancers as ductal carcinoma in-situ (DCIS) and lobular carcinoma in-situ (LCIS).

The ACS defines in-situ as “in its original place” which means it has not spread. Invasive cancers spread to the surrounding breast tissues. While there are other types of breast cancer, these four are the most common.

Invasive or Infiltrating Ductal Carcinoma (IDC)

IDC constitutes about 80% of all invasive breast cancers. In fact, according to the ACS, more than 180,000 women are diagnosed with IDC each year. IDC begins in the milk ducts of the breast and typically affects women over the age of 55.

It is important to know that in the beginning, IDC may not show symptoms. It is not unusual for IDC to be diagnosed through annual mammographic screening tests. On the other hand, according to the ACS, the first sign of IDC breast cancer could be:

  • Lump in the breast
  • Swelling of your breast
  • Skin irritation or skin deformation called dimpling
  • Pain
  • Nipple pain or the nipple turning inward
  • Redness, scaliness, or thickening of the skin
  • Nipple discharge other than milk
  • Lump in the underarm area

Invasive or Infiltrating Lobular Carcinoma (ILC)

ILC constitutes about 10% of all invasive breast cancers. ILC is the second most common type of breast cancer. ILC begins in the milk-producing lobules which empty into the ducts carrying milk to the nipple. Over time, ILC can break through the walls of the lobule and spread via the circulatory and lymphatic systems. According to the ACS, ILC tends to occur later in life than IDC.

Like IDC, ILC is diagnosed using mammographic screening tests. However, ILC can be more difficult to see and identify on mammograms because ILC cancer cells typically spread to the surrounding connective tissue in a line formation rather than forming a lump. Sometimes, the first sign of ILC can be thickening or hardening of the breast which can be felt. According to the ACS, the first sign of ILC breast cancer could be:

  • Swelling of all or part of your breast
  • Skin irritation or skin deformation called dimpling
  • Breast pain
  • Nipple pain
  • Redness, scaliness, or thickening of the nipple or skin covering your breast
  • Nipple discharge other than breast milk
  • Lump in the underarm area

Ductal Carcinoma In-Situ (DCIS)

DCIS is the most common form of non-invasive breast cancer. According to the ACS, about 60,000 cases of DCIS are diagnosed in the US each year. Starting in the ducts which carry milk to the nipple is non-invasive because it does not spread to the surrounding breast tissue.

The ACS defines in-situ as “in its original place.” Because DCIS does not spread to the surrounding tissue, it is not considered life-threatening. However, DCIS has been known to cause invasive carcinoma over time. The ACS explains that with DCIS, you are at higher risk for cancer to come back or reoccur. In fact, most cancers reoccur within 5 to 10 years after your initial diagnosis and happen in less than 30% of women.

Lobular Carcinoma In-Situ (LCIS)

LCIS occurs when cancer cells grow within the lobules of your breast and don’t spread to the surrounding tissue. If you are diagnosed with LCIS, you could have more than one lobule affected. According to the ACS, LCIS is not a true breast cancer and is commonly known as a “lobular neoplasia” or a collection of abnormal cells. As with DCIS, if you are diagnosed with LCIS, you are at increased risk of developing invasive breast cancer over time. LCIS is usually diagnosed before menopause (pre-menopausal) typically between the ages of 40 and 50. In fact, according to the ACS, less than 10% of women diagnosed with LCIS have already gone through menopause. LCIS is not as common of a condition as the other types of breast cancers.

Identifying Breast Cancer

Breast cancers can grow over a period and are typically identified through breast imaging techniques. Specifically, mammography, ultrasound, and MRI are used to identify breast cancers. But before having a mammogram, it is important for you to do a self-breast exam (best done during a shower) and ask your health care provider to do a clinical breast exam.

An annual screening mammogram is also necessary to identify breast cancer early. Early detection results in early treatment which results in better outcomes, faster cure, and longer survival. An annual breast cancer screening mammogram is best when performed digitally, in three dimensions (3D), by a board-certified radiologist who is an expert at detecting breast cancer.

Breast cancer can be difficult to see on a mammogram, but mammography along with a self-breast and a clinical breast exam is the key to identify breast cancer. If something suspicious is seen on the screening mammogram, you may be asked to have additional diagnostic tests including additional mammographic views along with ultrasound, and MRI.

These diagnostic tools are critical to accurately diagnosing/identifying your breast cancer. If the radiologist believes that in their expert opinion they require more information to accurately diagnose breast cancer, they may ask to perform a biopsy in order to obtain a sample of cells seen on your images.


A breast cancer diagnosis can be stressful, create anxiety, and is emotionally draining, but don’t panic. Educating yourself about breast cancer, and a timely diagnosis with accurate results can help develop a successful treatment plan. The worst thing anyone can do is ignore the issue which will lead to worse outcomes. In our next article, we will discuss some of the terminology associated with breast cancer and treatment options to consider for a successful outcome.


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