Metastatic breast cancer in the bones originates from breast tissue but spreads to the bones. This is an advanced form of cancer and treatments involve managing symptoms rather than curing the cancer.

Breast cancer is the second most common cancer in females, and it can also affect males. When breast cancer develops, it can spread to various parts of the body, which doctors refer to as metastasis. Some common sites for breast cancer metastasis are the bones, brains, lungs, and liver.

A diagnosis of metastatic breast cancer in the bones can be concerning. However, with appropriate care, people may be able to maintain a good quality of life.

In this article, we discuss metastatic breast cancer in the bones, including the causes, diagnosis, and treatment options. We also consider the outlook for people with the disease.

A person holding their neck in pain after experiencing discomfort due to metastatic breast cancer in the bones.Share on Pinterest
Robert Niederbrach/EyeEm/Getty Images

Metastatic cancer is cancer that has spread beyond its initial site to other parts of the body. In many cases, doctors refer to metastatic cancer as stage 4 cancer.

In people with breast cancer, a metastatic tumor develops when cancerous cells break away from the breast and come together in a different part of the body.

The cells can spread to different areas of the body, depending on the type of cancer. Places where metastatic breast cancer typically occurs include the:

The bones are the part of the body where metastatic breast cancer tumors most commonly form. Any type of cancer can spread to the bones, but 80% of bone metastases come from breast cancer, prostate cancer, or lung cancer.

Breast cancer metastases can form in any part of the skeleton, but the cancer usually spreads to bones in the:

  • spine
  • ribs
  • pelvis
  • arms
  • legs

Metastatic tumors can develop in the bones before a person is even aware that they have breast cancer. On the other hand, the metastatic tumors may not form until years after a person receives breast cancer treatment.

Metastatic cancer in the bones can lead to a decline in a person’s quality of life, and it can be fatal. However, some people continue to live a full and long life after diagnosis.

A person’s outlook varies depending on:

  • how far the cancer has spread
  • whether people experience skeletal-related events, such as bone fractures or spinal cord compression
  • whether people use treatment to reduce tumors

Some studies suggest that the average 1-year survival rate for people with metastatic bone cancer is 40–59%. However, the American Cancer Society states that people with distant breast cancer are 28% as likely to live for at least another 5 years as those without this condition.

A 2017 study in Danish people suggests that the 1-year survival rate among people with metastatic bone cancer is slightly higher, at 51%, when the cancer began in the breast than when it originated in the lungs or prostate. The authors note that most people live for 12–33 months after a diagnosis of metastatic cancer in the bones.

When breast cancer metastasizes, it causes tumor cells to grow and form disruptive structures on the bones.

Bone remodeling, in which new bone tissue replaces old bone tissue to keep the body strong, is an important process that occurs throughout a person’s life.

Metastatic cancer in the bones affects the process of bone remodeling. The tumors that develop on the bones can be osteolytic, meaning that they reduce bone tissue, or osteoblastic, meaning that they cause an overproduction of bone.

The symptoms of bone metastasis may include:

  • bone pain
  • fracture from bone weakness
  • nerve compression

If a person is experiencing symptoms and thinks that they might have bone metastasis, they should contact a doctor for a diagnosis.

Doctors typically use at least one imaging scan when assessing for bone metastasis. Possible imaging tests include:

Bone metastasis can cause calcium and alkaline phosphatase (ALP) levels to increase. Therefore, a doctor may test for higher levels than usual using a blood test.

Additionally, a biopsy may help determine whether a person has the condition. In this case, with guidance from a CT scan, a doctor will use a needle to collect a tissue sample from the potentially cancerous area of bone. Lab technicians will analyze the sample for signs of cancer.

Bone metastasis is almost always incurable. Therefore, the treatment options typically focus on controlling the cancer by reducing or stopping its growth, as well as minimizing symptoms through palliative care.

The goal of the treatment plan will determine a person’s treatment options.

Some people may use bone-strengthening drugs, which include pamidronate, zoledronic acid, and denosumab. These drugs can help by:

  • reducing the likelihood of skeletal-related events, such as fractures
  • relieving pain
  • reducing the need for other treatment options, such as chemotherapy

Other treatment options include:

People sometimes enter clinical trials when they are exploring treatment options, as they may find opportunities that are not yet generally available.

The type and severity of symptoms that a person experiences depend on the size of the metastatic tumors and where they are within the body.

Some people may choose to add complementary and holistic medicine to their treatment plan and use methods such as acupuncture, meditation, and hypnosis.

These techniques may reduce the severity of a person’s symptoms and improve their quality of life, but they should not be a substitute for medical treatment. If a person chooses to use such methods, they should make their doctor aware.

Having cancer can cause a range of emotions, but no one has to go through it alone. Support is available in the form of counseling, support groups, pain clinics, and more. A doctor may be able to offer a person advice on the options in their local area.

Breast cancer can spread to the bones through the process of metastasis. Metastasis occurs during stage 4 cancer, but it can happen any time from when a person first becomes aware that they have breast cancer to years after their recovery.

Treatments are available to control and reduce the cancer and ease symptoms. These can prolong and improve the quality of life for a person with bone metastasis and may allow them to live a long and productive life.

Read this article in Spanish.