Breast cancer cells sometimes metastasize — travel from the breast to a new place and start growing in a different part of the body. Metastatic breast cancer is also known as stage 4 breast cancer. The most common location breast cancer spreads to is the bones.

One large study found that among those with metastatic disease, about 40 percent had breast cancer spread only to the bones, while an additional one-third of people had tumors in multiple parts of the body, often including the bones.

It’s important to be aware of the symptoms of bone metastasis if you have received a breast cancer diagnosis. Knowing what to watch out for could help you find signs of new cancer early, when it is more treatable. Several therapies can help prevent cancer from spreading to your bones or help treat metastases (or mets, tumors located in other organs or tissues besides your breast).

Bone metastases don’t always cause symptoms. However, make sure to tell your oncologist if you notice any health changes, including the following signs and symptoms, which could suggest breast cancer bone metastasis.

1. Bone Pain

Cancer cells are more likely to spread to some bones than others. One of the most common sites of bone metastasis is the spine, which can lead to back pain. Hip pain caused by cancer cells growing in the pelvic bones or femur (thigh bone) is also common. Bone pain may affect any other bones, such as your ribs, causing pain.

At first, bone pain caused by metastasis often comes in waves. You may have pain for a short period and then feel better. Eventually, the pain will occur more often until it stops going away. This pain also tends to get worse at night or when you sit or lie down.

Pain in breast cancer can have other causes. Your health care team can help identify and manage any pain.

2. Broken Bones

If you suddenly feel a lot of pain and can’t move a particular area, you may have a broken bone or a fracture. Breaks happen when metastases weaken the nearby bone. Other symptoms of a broken bone include swelling, bruising, a bump, or tenderness when you touch the area.

3. Leaking Urine

Urinary incontinence occurs when you unintentionally leak some urine. For people with breast cancer, this may be a sign of spinal cord compression. Your spinal cord is a bundle of nerves that runs from your brain down your spine. If breast cancer spreads to your vertebrae (small circular bones in your spine), one vertebra may break and press against your spinal cord, leading to compression and various symptoms.

Urinary incontinence isn’t always a symptom of breast cancer metastasis. It can also occur due to urinary tract and vaginal infections, diabetes, arthritis, Parkinson’s disease, or medications. Additionally, urinary incontinence is more common in older adults. However, tell your oncologist if you experience this as a new symptom while living with breast cancer.

4. Inability To Control Bowel Movements

Another sign of breast cancer spreading to bones is bowel incontinence — loss of bowel control. This also occurs because of spinal cord compression. This symptom may cause stool to come out when you don’t want it to. It can also indicate spinal cord compression due to bone metastasis. On the other hand, spinal cord compression may also make it more difficult to go to the bathroom.

5. Other Symptoms of Spinal Cord Compression

Spinal cord compression can also lead to other issues, including neck pain or stiffness, back pain, nerve pain in your buttocks or legs, limping, an inability to have sex, or numbness and weakness in a certain part of your body, such as your hand, leg, or abdomen.

Spinal cord compression needs to be treated right away. It can worsen quickly, which can lead to paralysis. Contact your doctor or go to the emergency department if you have breast cancer and think you are having signs of spinal cord compression.

6. High Calcium Levels

Tumors in your bones can cause your bone tissue to break down. The bones store much of your body’s calcium, which they release into the blood when they become damaged or weakened. This is called hypercalcemia.

High levels of calcium in the blood can lead to additional symptoms, such as:

• An upset stomach, nausea, or vomiting
• Loss of appetite
• Constipation
• Extreme thirst or increased urination
• Heart palpitations (irregular heartbeat)
• Tiredness or weakness
• Confusion
• Depression

Hypercalcemia can be detected with a simple blood test.

Treatments for Bone Metastasis

If there is a chance you have bone metastases, your doctor may recommend additional tests for diagnosis, including an X-ray, a bone scan, a CT scan, or an MRI.

Several treatment options can help kill cancer cells in your bones, strengthen your bones, and reduce symptoms.

Cancer-Killing Treatments

Targeted therapy drugs can help treat bone metastases if your cancer cells contain certain gene or protein changes. HER2-positive cancer (breast cancer that contains high levels of a protein called HER2) can often be treated with medications like trastuzumab (Herceptin) or pertuzumab (Perjeta). Additionally, breast cancer cells that contain estrogen receptor (ER) or progesterone receptor (PR) can be treated with other targeted therapies like palbociclib (Ibrance) or everolimus (Afinitor).

Targeted therapy drugs are often given along with chemotherapy. Additionally, hormone therapy may help treat bone metastases if your breast cancer is ER- or PR-positive.

Other cancer treatments like radiation therapy or surgery may also help if you have only a small number of metastases.

Bone-Strengthening Treatments

Two types of medications can make your bones stronger, reducing your risk of serious problems if you have bone metastases. They can also reduce the risk of cancer cells spreading to your bones.

Bisphosphonates such as pamidronate (Aredia) and zoledronic acid (Zometa) slow down and prevent bone loss. They are given intravenously every three to four weeks or every three months. Another option is the RANK ligand inhibitor denosumab (sold as Prolia and Xgeva). This medication attaches to osteoclasts (cells that break down bone) and stops them from dissolving too much bone tissue. Denosumab is given as an injection about once a month.

These treatments can lower the chances that you will break a bone or be diagnosed with hypercalcemia. They can also ease pain and stop bone metastases from growing bigger. However, in some cases, they cause a rare side effect called osteonecrosis of the jaw, in which part of the jawbone dies. If you need bone-strengthening drugs, your doctor may recommend getting any necessary dental work done before starting them.

Treatments To Relieve Symptoms

Bone pain can be treated with different types of painkillers. Over-the-counter options such as ibuprofen and acetaminophen may be enough to ease mild aches and pains. However, ask your doctor before taking these, as you might need to stay away from certain medications if you have conditions like heart failure or kidney disease.

You may be able to take stronger painkillers if you have severe pain. Your doctor may prescribe opioids like morphine or oxycodone, which may lead to nausea, fatigue, or constipation. Steroid medications can also ease pain and swelling.

Treatments often used to kill cancer cells, such as radiation, chemotherapy, and hormone therapy, may also be used to relieve symptoms. This may include intravenous radiation, in which a radioactive substance is delivered through a vein and travels to your bones to kill cancer cells. These therapies can shrink bone metastases, which can lessen pain and help prevent bone fractures.

Ablation is a technique that uses extreme heat, freezing temperatures, or electrical currents to destroy or shrink tumors in the bone. This approach can help relieve pain caused by metastasis.

Your doctor may also recommend surgery to fix a broken bone or strengthen a bone that is at risk of breaking. Doctors can use metal plates, screws, or bone cement to stabilize your bones.

Physical therapy can also help you build strength and flexibility and allow you to move around more easily. This type of treatment may help you better deal with or prevent pain and improve your quality of life.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 59,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Do you have metastatic breast cancer? Have your doctors found metastases in your bones? Share your experiences in the comments below, or start a conversation by posting on your Activities page.