When a cancer spreads to the bones, it’s called bone metastasis. It’s also called metastatic bone disease or secondary bone cancer, because the cancer didn’t start in the bones.

Bone metastasis usually occurs in people who have been previously diagnosed with cancer or who have advanced cancer. But sometimes the pain of bone metastasis may be the first sign of cancer.

Bone metastasis often means cancer has progressed to an advanced stage that isn’t curable. But not all bone metastasis progresses rapidly. In some cases, it progresses more slowly and can be treated as a chronic condition that needs careful management.

Bone metastasis may not be curable, but treatment may help people live longer and feel better.

The exact mechanism of how cancer cells metastasize to the bones isn’t fully known. It’s a very active area of scientific research. New understanding of how metastasis works is continuing to lead to new methods of treatment.

The most common cancers that spread to bone are breast, prostate, and lung. But many other cancers can metastasize to bone, including:

  • thyroid
  • kidney
  • melanoma
  • lymphoma
  • sarcoma
  • uterine
  • gastrointestinal

Bone is the third most common place for cancer to spread. The lungs and liver are the first two.

Cancer cells may metastasize to only one of your bones or to many at the same time. The most usual sites for bone metastases are your:

  • spine
  • ribs
  • hips
  • sternum
  • skull

Types of bone metastases

Normally your bones are constantly changing. New bone tissue is being formed and old bone tissue is breaking down into minerals that circulate in your blood. This process is called remodeling.

Cancer cells upset the normal process of bone remodeling, causing bones to become weak or too dense, depending on the type of bone cells affected.

Your bone metastases may be:

  • osteoblastic, if there are too many new bone cells (this often happens with metastasized prostate cancer)
  • osteolytic, if too much bone is destroyed (this often happens with metastasized breast cancer)

In some cases, your bones may have both types of metastases.

The research on cancer metastasis is rapidly growing. As researchers better understand the mechanisms of bone metastasis, new drugs and other treatments are being developed. These target particular processes in cells involved in how the cancer cells invade and grow in bones.

The use of nanoparticles (billionths of a meter in size) to deliver drugs is very encouraging. These tiny particles are able to deliver drugs to the bone with minimal toxicity to the person with cancer.

Rapidly treating bone metastasis can lead to a better outcome, by reducing pain and bone fractures. This improves quality of life of the person with bone metastasis.

Survival rates for people with bone metastases vary greatly by cancer type and stage. Your general health condition and the type of treatment you received for the primary cancer are additional factors.

Discuss your particular situation with your doctor. Remember that survival rates are averages gathered from large numbers of people. Also, survival data may reflect statistics from a period before the most recent treatment advances.

A large-scale 2017 study of the 10 most common cancers with bone metastasis found:

  • Lung cancer had the lowest 1-year survival rate after bone metastasis (10 percent).
  • Breast cancer had the highest 1-year survival rate after bone metastasis (51 percent).
  • Having metastases in bone and also in other sites was found to decrease the survival rate.

Here are some typical figures from a 2018 study of common cancers and bone metastasis:

Type of cancerPercent of cases that metastasize after 5 years5-year survival rate after metastasis

Each person’s treatment for bone metastases is individualized and requires a multidisciplinary approach. Your treatment plan will depend on:

  • the type of primary cancer you have
  • the stage of your cancer
  • which bones are involved
  • prior cancer treatments
  • your overall health

You’re likely to have a combination of therapies that may include:

  • radiation to slow metastasis growth and reduce pain
  • chemotherapy to kill cancer cells and reduce tumor size
  • hormone therapy to reduce the hormones known to be involved with breast and prostate cancer
  • painkillers and steroids for pain relief
  • drugs that specifically target bones
  • surgery if necessary to stabilize your bone, fix a break, and help with pain
  • physical therapy to strengthen your muscles and help you with mobility
  • extreme heat or cold that targets cancer cells and may relieve pain

Bone-targeting treatment

Specific drugs that target bones are an important part of therapy and a developing research area.

It’s important to begin bone-targeting treatment as soon as possible, and not wait until you have a fracture or other bone injury. A breast cancer study reported a lower risk of bone complications for people who started treatment within 6 months of a bone metastasis diagnosis.

Bone-targeting drugs currently used include:

  • denosumab, a human antibody that’s effective in preventing bone loss and bone deterioration
  • bisphosphonates, bone-building drugs similar to those used in osteoporosis; these strengthen bones and reduce the pain of metastases
  • trastuzumab (Herceptin), which targets particular breast cancer cells
  • bortezomib, which inhibits the proteasomes that break down proteins; it’s approved for treating multiple myeloma and under study for other cancers
  • radioactive elements (radiopharmaceuticals), which are injected into a vein and find and kill cancer cells in the bones

As we learn more about the mechanisms of how cancer cells invade and disrupt bones, scientists develop new ways of targeting and slowing these cancer cells.

Note that most cancer treatments have side effects. Discuss these with your doctors and evaluate the benefits versus risks for your treatment.

New developments

Ask your doctors about new developments in the field that may help you. Drug development for cancer is a fast-moving research area. The medical literature has articles on new possibilities under development and testing.

For example, the use of nanoparticles has the promise of enhancing both current drugs and new drugs under development. Nanoparticles can be used to deliver drugs to the metastasis site with fewer side effects.

Clinical trials

You may be eligible for a clinical trial. Clinical trials test out new drugs, experiment with new treatments, and compare the outcome of existing treatment combinations. There’s no guarantee that a new treatment will help you. But participation in trials helps compile a knowledge-base for future treatments.

The National Cancer Institute has a site where you and your doctor can search for clinical trials.

You can also check on bone metastases clinical trials at CenterWatch, a free listing service. You can sign up to be notified when a clinical trial matches what you’re looking for.

Support groups

An estimated 330,000 people are living with bone metastases in the United States.

The American Cancer Society (ACS) can help you connect with others in your area who have bone metastases or with caregivers of people with metastases. You can also connect up with a support group online. The ACS also offers help in finding services you may need.

Talking with other people who are going through the same treatment (or pain) that you are can help. You may learn new ideas for coping, and you may be able to help others.

Caretakers of people with bone metastases may also benefit from a support group.