How Metastatic Breast Cancer Is Diagnosed

Diagnosing metastatic breast cancer can involve different tests and lab procedures, depending on where the cancer metastasizes (spreads). For example, the location of the cancer may spread to the lungs, bone, brain, or liver. The tests used to diagnose metastatic breast cancer may differ for each area or organ that is involved.

Metastasis involves the spread of cancer to distant areas or organs of the body. When it spreads to two or more distant areas, this is known as metastatic cancer or stage 4 disease. Breast cancer that spreads to local areas such as the lymph nodes is not considered metastasis, but rather locally advanced breast cancer.

In most cases, metastatic cancer is diagnosed after a cancer has already been treated at an earlier stage. But in 6%–10% of all cases of breast cancer, the cancer has already spread at initial diagnosis and is considered stage 4. Therefore, it’s easy to understand why early diagnosis of breast cancer is so vital.

Breast cancer can spread to different parts of the body, most commonly to the bones, the brain, lungs, liver, or even to the skin. Sometimes, other organs are involved. It's important to note that breast cancer that spreads to any of these sites is not the same as cancers that originate in these areas.


Self-Checks/At-Home Testing

Although for most types of metastatic breast cancer there really isn’t a standard home test or self-check to perform, there is one type that can be screened for by doing regular breast exams. Known as secondary breast cancer, skin metastasis spreads to the skin through the blood or lymph system.

Approximately 20% of those with secondary breast cancer will develop skin metastasis. The most common areas affected are regions near the site of the original breast cancer, such as the skin of the chest or around the surgical scar. But other areas can be involved as well.

When performing self-exams at home, check for signs and symptoms such as:

  • A change in the color of the skin
  • A rash that doesn’t go away
  • A small lump or nodule that is painless, but firm
  • Several nodules of various sizes
  • Redness or inflammation that looks like a skin infection
  • Swelling of the arm, hand, or breast area (called lymphedema)
  • Pain, bleeding, or odor

Metastasis to the liver does not always cause symptoms initially, but in some instances, liver metastasis can cause symptoms. The symptoms to be aware of during an at-home self-screening include:

  • Pain in the midsection
  • Weakness
  • Fatigue
  • Poor appetite
  • Weight loss
  • Fever
  • Abdominal bloating
  • Swelling (in the lower extremities)
  • Jaundice (a yellow tinge to the skin or whites of the eyes)

Physical Examination

A manual examination, or palpation, of the breasts, the armpit area (lymph nodes), and the area around the surgical scar, is performed by the healthcare provider to detect whether a tumor has grown back.

The healthcare provider will also do a general physical exam to assess for any problems (such as nodules or pain) anywhere else in the body.

Lab Tests

If a lump is detected, it will be biopsied (a test to check for cancer cells). A biopsy is one of the most important tests when it comes to diagnosing metastatic breast cancer. A very small amount of the suspicious tissue is removed and then examined under a microscope. 

The biopsy can check for breast cancer cells that appear in other organs/areas of the body, including the liver, bone, lungs, lymph, skin, or body fluids. If a biopsy from the breast is positive, it’s considered cancer recurrence or a second breast cancer primary. This is different than metastasized cancer.

In addition to a biopsy, you may have blood tests and urine tests performed to check your general state of health as well as specific signs of involvement of other sites, such as elevated liver enzymes.


If a person who has had breast cancer has general symptoms or is diagnosed with a recurrence of breast cancer, the healthcare provider will want to check to make sure the cancer has not metastasized. This can be done by using several different imaging tests.

The most common types of imaging tests used to evaluate breast cancer metastasis are:

If there are any suspicious results from these imaging tests, further testing will be ordered to more closely examine the involved area of the body. These may include computed tomography (CT) scans or positron-emission tomography (PET) scans.

If there are any suspicious results for any type of imaging test, a biopsy may also be performed.

Diagnostic Tests by Metastasis Site

The tests performed will differ based on the suspected site of metastasis. Here is what you may expect.

Diagnosis of Bone Metastasis

The most common area of the body where breast cancer metastasizes to is the bones. This occurs in over 50% of women with stage 4 breast cancer. Breast cancer can spread to any bone, but the most common sites include the pelvis, ribs, spine, and the long bones in the arms and legs. The tests involved in diagnosing bone metastasis include:

  • Bone scan
  • X-rays
  • CT scans
  • MRIs
  • PET scans

A blood test may also be ordered to check for bone metastasis. This test will check for high levels of calcium or another substance that is often elevated as a result of bone metastasis called ALP (alkaline phosphate.).

A bone biopsy may also be ordered to confirm bone metastasis. This involves using CT scans to help the physician guide a small needle into the area that is suspected of metastasis, to remove a sample of the tissue. The tissue is then examined in the lab to find out if it is cancerous.

Diagnosis of Lung Metastasis

To perform diagnostic tests for lung cancer metastasis, the healthcare provider will employ the help of a pulmonologist, a thoracic surgeon, or a radiologist. These specialists diagnose and treat lung conditions. Tests that may be performed to diagnose lung metastasis include:

  • Examination of a mucus sample under a microscope
  • A lung tissue biopsy (to examine a sample of the lung tissue under a microscope)
  • Bronchoscopy (inserting a flexible tube into the airways of the lungs to examine suspected tissue and remove a sample if needed)
  • Lung needle biopsy (inserting a needle through the skin under guided imaging scans, such as CT scans, to remove a sample of tissue)
  • Surgery (to remove the suspicious area of the lung for examination)

When the healthcare provider removes tissue from the lung, there are two primary goals, which are:

  1. Determining if breast cancer is in the suspicious area of the lung
  2. Testing the tissue to discover its characteristics that may impact treatment choices (such as hormone receptor status and human epidermal growth factor receptor 2 (HER2 status): The hormone receptor status is associated with how hormones influence the tumor growth. HER2 proteins are found on the surface of the cell and provide information on the tumor’s biology and aggressiveness. This knowledge (about the HER2 and hormone receptor status) can impact which type of treatment is selected.

Note, it’s important to keep in mind that metastatic breast cancer isn’t always identical to the original breast cancer.

Diagnosis of Brain Metastasis

An MRI is ordered when the healthcare provider suspects brain cancer. Often the MRI study will involve contrast solution. The contrast solution is administered intravenously, and it travels through the veins to the brain. This makes the images in the study easier to decipher. An MRI study detects whether an unusual finding in the brain is, in fact, metastatic breast cancer.

A brain biopsy could be ordered to confirm the diagnosis of metastatic brain cancer, but this is rare. In this instance, the surgeon must make an opening in the skull by drilling a small hole in the skull and then use imaging studies to direct a hollow needle to remove some of the tissue from the brain tumor. The tissue is then examined by a pathologist (a physician specializing in laboratory medicine) in the lab.

Diagnosis of Liver Metastasis

When breast cancer metastasizes to the liver, there are usually no initial symptoms. Therefore, a liver function test may be a standard blood test ordered by the healthcare provider during a follow-up exam for those who have been diagnosed with breast cancer. The liver function test involves removing blood from a vein, and then sending the blood sample to the lab to test for certain levels of enzymes (called liver enzymes) and protein in the blood. Abnormal levels indicate liver damage or liver disease.

Other tests commonly used to diagnose liver metastasis include imaging tests such as:

  • MRI
  • CT scans
  • Ultrasound and/or PET scan
  • A combined PET/CT scan

In addition, the diagnosing healthcare provider may order a sample of the tissue in the suspicious area; this is called a liver biopsy. A liver biopsy is obtained using imaging tools (such as a CT scan) to guide the physician in inserting a small needle through the skin to collect the liver tissue sample.

Another method of obtaining the liver tissue for biopsy is called a laparoscopy. This involves using a specialized scope to operate, through a very small incision in the abdomen to remove the suspicious tissue. The tissue samples are then examined in the lab to determine if they contain breast cancer tissue. If the tissue is cancerous, it can further be tested to determine its hormone receptor and HER2 status, which can guide the use of targeted therapies.

Differential Diagnosis

The process of differentiating between two (or more) medical conditions that have the same or similar symptoms is called a differential diagnosis. One example is exploring whether respiratory symptoms are due to a respiratory infection (the common cold, influenza, or pneumonia, for instance) or are a sign of lung metastasis. This is particularly helpful if it’s flu season or if a person is prone to chronic respiratory infections.

In general, any unusual symptoms (including respiratory symptoms such as cough and fever) that last more than a week or two should be checked out by the healthcare provider.

Anytime a tumor is found, it’s important for the healthcare provider to find out if it’s a metastasis of breast cancer or whether it is a primary tumor of the brain, lung, or other area of the body. This is particularly important because different types of cancers require treatment that is not the same as metastatic breast cancer treatment.

A Word From Verywell

Getting a diagnosis of metastatic breast cancer can be quite overwhelming, particularly considering that you have already undergone the original breast cancer diagnosis and gone through treatment. You may experience many emotions. These may include depression, anger, and fear. Some women may begin to blame the doctor who first treated the breast cancer or they may even blame themselves, feeling they should have been able to beat the cancer. 

Other people deal with the diagnosis without any emotion at all. What’s important to realize is that there is no “right way” of dealing with a diagnosis of metastatic breast cancer. Any emotion (or lack of emotion) felt is OK and should simply be accepted and dealt with. 

Many people with breast cancer survive and live long, productive lives after diagnosis. Modern medicine is equipped to help people deal with all aspects of the condition after diagnosis, including supportive/palliative care to provide measures to avoid discomfort. New and improved treatment modalities are being developed every day. Today more people than ever before are continuing to live a productive life while being treated for metastatic breast cancer.

You may want to consider reaching out to join a breast cancer survivor’s group or connect with people in other types of support groups. You may find hope and the strength to continue your journey through cancer and live your best life.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.