Breast cancer is a diverse group of diseases with several distinct types, each with its own characteristics and behaviors. No two persons will have the exact same breast cancer profile because the cancer is derived from each person’s unique genetic mutation.

If you are diagnosed with breast cancer, tests will be performed to determine the type of breast cancer and stage, including if the cancer has spread to other parts of the body.

What are the Main Types of Breast Cancer?

Each type of breast cancer may require different approaches to diagnosis, treatment, and management, so it’s crucial for patients to work closely with their healthcare team to develop a personalized treatment plan tailored to their specific condition. Early detection through regular screenings and awareness of breast cancer risk factors can also play a significant role in improving outcomes.

What is Ductal Carcinoma In Situ (DCIS)?

Ductal Carcinoma In Situ (DCIS) is considered the earliest form of breast cancer. DCIS is a non-invasive breast cancer where abnormal cells are found in the lining of a breast duct but have not spread outside the duct. It is often considered a precancerous condition.

Invasive Lobular Carcinoma
Though visible on a mammogram, Invasive Lobular Carcinoma can be difficult to detect.

What is Invasive Ductal Carcinoma (IDC)?

Invasive Ductal Carcinoma (IDC) is the most common type of breast cancer. IDC begins in the milk ducts but then breaks through the duct wall and invades the surrounding breast tissue. It can also spread to other parts of the body if left untreated. This is why it is referred to as invasive.

What is Invasive Lobular Carcinoma?

Invasive Lobular Carcinoma (ILC) originates in the lobules, which is the milk-producing glands of the breast. It has a tendency to spread in a single-file pattern, making it harder to detect through mammograms and potentially more challenging to treat.

What is Invasive Mucinous Carcinoma?

Invasive Mucinous Carcinoma is a rare subtype of Invasive Ductal Carcinoma that is characterized by the presence of mucus-producing cancer cells. It tends to be less aggressive and is less likely to spread to the lymph nodes. Mucinous Carcinoma also has a better prognosis than some other invasive types of breast cancer.

What is Inflammatory Breast Cancer?

Inflammatory Breast Cancer (IBC) is a rare but aggressive form of breast cancer that usually presents with reddening and swelling of the skin rather than a distinctive mass. This type of breast cancer only accounts for 1% of all breast cancer cases in the United States. It is called inflammatory because the affected breast often appears swollen, red, and feels warm to the touch. IBC tends to grow and spread quickly, making early diagnosis and aggressive treatment essential.

What is Metastatic Breast Cancer?

Metastatic Breast Cancer occurs when cancer cells have spread beyond the breast and nearby lymph nodes to other parts of the body (stage IV breast cancer). The common areas of metastasis are the brain, liver, bones, and lungs.  Breast cancer cells spread from the original tumor through the blood stream and the lymphatic system. Metastatic Breast Cance is considered advanced and may not be curable, but it can be managed with various treatments to extend life and improve quality of life.

How does Breast Cancer Develop?

Breast cancer develops because of several interdependent factors including genetic, hormonal, and environmental. It typically begins when normal cells in the breast tissue mutate causing them to divide and grow uncontrollably. While the causes of these mutations may not be identifiable, several risk factors have been well established. These include a family history of breast cancer, certain inherited gene mutations (such as BRCA1 and BRCA2), hormonal influences (estrogen and progesterone), exposure to ionizing radiation, and lifestyle factors like excessive alcohol consumption, smoking, and obesity.

As these mutated cells continue to divide and accumulate, they can form a mass or lump in the breast also known as a tumor. Some breast tumors are benign, meaning they are not cancerous and do not spread to other parts of the body.

Breast Cancer Progression benign - malignant

However, other tumors can be malignant, or cancerous, and have the potential to invade surrounding tissues (metastasis), spreading to other organs through the bloodstream or the lymphatic system. The stage and aggressiveness of breast cancer can vary. Therefore, early detection through regular screening, including regular mammograms, is crucial for effective treatment and improved outcomes. Treatment options for breast cancer may include surgery, radiation therapy, chemotherapy, hormone therapy, targeted therapy, or a combination of these, depending on the type and stage of the cancer.

Meet Our Breast Cancer Surgeons

The Margie Petersen Breast Center at Providence Saint John’s Health Center brings you some of the finest breast cancer care in Southern California.


The Breast Center can be reached at 310-582-7100 select option 2, then again select option 2. If you have questions regarding a new symptom or want to make an appointment for evaluation please call and a staff member will assist with navigating you in the right direction.

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