When breast cancer spreads to other sites in the body, doctors call this “metastasizing.” There are several ways cancer can spread in the body.

• Breast cancer can spread lymphatically from the breast into the chest wall underneath. The cancer cells take root and begin to grow in this new area.
• Lymphangitic spread occurs when cancer travels through the lymphatic system. Breast cancer often involves the nearby lymph nodes, so the cancer can enter the lymph circulatory system and take hold in different parts of the body.

• bones
• brain
• liver 
• lungs

A variety of tests can detect the spread of cancer. These tests typically aren’t performed unless your doctor thinks the cancer may have spread.

Before ordering them, your doctor will evaluate your tumor size, lymph node spread, and the specific symptoms you’re having.

The most common tests include:

• a chest X-ray
• a bone scan
• a CT scan
• an MRI scan
• an ultrasound
• a positron emission tomography (PET) scan

The type of test you end up having will depend on your medical history and symptoms. For example, if you or your doctor suspects the cancer may have spread to your abdomen, you may have an ultrasound.

CT and MRI scans can help your doctor visualize various parts of the body all at once. A PET scan can be helpful if your doctor thinks the cancer may have spread but isn’t sure where.

All of these tests are relatively noninvasive, and they shouldn’t require a hospital stay. You may be given special instructions before your test.

If you have a CT scan, for instance, you may need to drink an oral contrast agent to help outline different features inside your body.

If you have any questions or concerns, don’t hesitate to call the office conducting the test for clarification.

What are the stages of breast cancer?

The American Cancer Society (ACS) determines each stage of breast cancer as pathologic or clinical. Doctors examine the tissues removed during an operation for the pathologic stage. If surgery cannot happen, the clinical stage is based on a physical exam, imaging tests, and biopsy results.

The pathologic stage is mainly about understanding what is learned from the cancer during surgery.

Within the staging system, there’s also anatomic staging and prognostic staging:

• Anatomic staging is based on the size of the tumor and the involvement of the lymph nodes.
• Prognostic staging means the percentage of people with a particular score with a disease-specific survival of 5 years.

The biology of the tumor changes the prognostic stage compared to the anatomic stage. 

Your doctor identifies the stage of cancer by determining:

• whether the cancer is invasive or noninvasive
• the size of the tumor 
• the number of lymph nodes affected
• the cancer’s presence in other parts of the body

Your doctor can tell you more about your outlook and appropriate treatment options once the stage is determined through various tests.

The five clinical stages of breast cancer are:

Stage 0

In stage 0, the cancer is considered noninvasive. The types of stage 0 breast cancer include:

• Ductal carcinoma in situ (DCIS): In DCIS, the cancer is found inside the lining of the milk ducts but hasn’t spread to other breast tissue. There are times when DCIS is considered a pre-malignant lesion and not considered a “cancer.”

Pre-cancerous lesions are also considered stage 0 and do not affect the longevity of life.

Stage 0 breast cancer is highly treatable.

Stage 1

At this stage, the cancer is considered invasive but localized. In stage 1, the cancer is smaller than 2 centimeters (cm). It hasn’t spread to the surrounding lymph nodes.

As with stage 0, stage 1 breast cancer is highly treatable.

Stage 2

The cancer is invasive in stage 2. This stage is divided into 2A and 2B:

• In stage 2A, the cancer has spread to your lymph nodes. Alternatively, the tumor might be less than 2 cm in size and involve the lymph nodes. The tumor may measure between 2 and 5 cm but doesn’t involve your lymph nodes.
• In stage 2B, the tumor size is larger. You may be diagnosed with 2B if your tumor is between 2–5 cm and it has spread to four or fewer lymph nodes. Otherwise, the tumor might be bigger than 5 cm with no lymph node spread.

You may require stronger treatment than with the earlier stages. However, stage 2 breast cancers are still highly treatable.

Stage 3

Your cancer is considered invasive and advanced if it reaches stage 3, but at this stage it hasn’t yet spread to your other organs.

This stage is divided into the subsets 3A, 3B, and 3C. This is also known as the pathologic stage, in which results stem from the surgery examining the removed tissue.

• In stage 3A, your tumor may be smaller than 2 cm, but there are between four and nine affected lymph nodes. Tumor size at this stage may be larger than 5 cm and involve small gatherings of cells in your lymph nodes. The cancer may have also spread into the lymph nodes in your underarm and breastbone.
• In stage 3B, the tumor can be any size. At this point, it has also spread into your breastbone or skin and affects up to nine lymph nodes.
• In stage 3C, the cancer may have spread to over 10 lymph nodes even if no tumor is present. The lymph nodes affected may be near your collarbone, underarm, or breastbone.

• brain
• bones
• lungs
• liver

Your doctor may try a variety of treatment options. The cancer is no longer curable but still treatable.