Back pain isn’t one of the hallmark symptoms of breast cancer. It’s more common to have symptoms like a lump in your breast, a change in the skin over your breast, or a change in your nipple.

Yet pain anywhere, including in your back, can be a sign of breast cancer that has spread. This is called metastatic breast cancer.

When cancer spreads, it can get into the bones and weaken them. Pain in the back could be a sign that a spinal bone has fractured or that the tumor is pressing on the spinal cord.

It’s important to remember that back pain is a very common condition. It’s much more commonly caused by conditions such as:

If the pain is severe and you have other breast cancer symptoms or a history of breast cancer, see your doctor to have it checked out.

When doctors diagnose breast cancer, they assign it a stage. That stage is based on whether the cancer has spread and, if so, how far it has spread.

Cancer stages are numbered 1 through 4. Stage 4 breast cancer is metastatic. That means it’s spread to other parts of the body, like the lungs, bones, liver, or brain.

Breast cancer can spread in a couple of different ways:

  • cancer cells from the breast can move into nearby tissues
  • cancer cells travel through the lymph vessels or blood vessels to distant sites

When breast cancer spreads to other organs, it’s still called breast cancer. Symptoms of metastatic breast cancer depend on which organs it has invaded. Back pain can be a sign that the cancer has spread to the bones.

Other symptoms of metastatic breast cancer include:

  • headaches, vision problems, seizures, nausea, or vomiting if it’s spread to the brain
  • yellow skin and eyes, abdominal pain, nausea and vomiting, and appetite loss if it’s spread to the liver
  • chronic cough, chest pain, and trouble breathing if it’s spread to the lungs

Metastatic breast cancer can also cause more general symptoms, such as:

  • fatigue
  • weight loss
  • appetite loss

If you have symptoms such as a breast lump, pain, nipple discharge, or a change in the shape or look of a breast, your doctor may do some or all of the following tests to see if you have breast cancer:

  • Mammograms use X-rays to take pictures of the breast. This screening test can show whether there’s a tumor inside the breast.
  • Ultrasound uses sound waves to create a picture of the breast. It can help a doctor tell whether a growth in the breast is solid, like a tumor, or filled with liquid, like a cyst.
  • MRI uses a powerful magnet and radio waves to create detailed pictures of the breast. These pictures can help a doctor identify any tumors.
  • Biopsy removes a sample of tissue from your breast. The cells are tested in a lab to see if they’re cancerous.

If the doctor suspects that cancer has spread, one or more of these tests can check where it is:

  • blood test for liver or bones
  • bone scan
  • X-rays or CT scan for chest or abdomen
  • MRI for the brain

Treatment will depend on where the cancer has spread and the type of breast cancer.

Hormone therapy drugs

These medications are used to treat hormone receptor-positive breast cancers. They work by depriving tumors of the hormone estrogen, which they need to grow. Hormone therapy drugs include:

  • aromatase inhibitors (AIs), such as anastrozole (Arimidex) and letrozole (Femara)
  • selective estrogen receptor down regulators (SERDs), such as fulvestrant (Faslodex)
  • selective estrogen receptor modulators (SERMs), such as tamoxifen (Nolvadex) and toremifene

Anti-HER2 drugs

HER2-positive breast cancer cells have large amounts of a protein called HER2 on their surface. This protein helps them grow. Anti-HER2 drugs like trastuzumab (Herceptin) and pertuzumab (Perjeta) slow or stop the growth of these cancer cells.

Chemotherapy

Chemotherapy slows the growth of cancer cells in the body. You’ll usually get these drugs in cycles of 21 or 28 days.

Radiation therapy

Radiation destroys cancer cells or slows their growth. Your doctor might give you radiation in addition to systemic therapies.

Your doctor can treat breast cancer that’s spread to the bones with medications like bisphosphonates or denosumab (Prolia). These slow bone damage and prevent fractures that can cause pain. These drugs are administered through a vein or as an injection.

To help you manage pain, your doctor might suggest one or more of the following:

  • Over-the-counter pain relievers such as acetaminophen (Tylenol), aspirin, ibuprofen (Motrin, Advil), or naproxen (Aleve) help with mild pain.
  • Opioid drugs like morphine (MS Contin), codeine, oxycodone (Roxicodone, Oxaydo), and hydrocodone (Tussigon) can help with more severe pain. However, they can become addictive.
  • Steroid drugs like prednisone can help with pain caused by swelling.

You can also try nondrug pain relief methods, such as breathing techniques, heat or cold, and distraction.

If your back pain isn’t caused by cancer, treatments such as massage therapy, physical therapy, and stretching may help relieve pain.

Back pain isn’t usually a sign of metastatic breast cancer, but it’s possible in some cases. Metastatic breast cancer isn’t curable, but you can manage it.

You can slow the progress of your cancer with treatments like hormone therapy, chemotherapy, and radiation. These treatments can prolong and improve your quality of life.

You also can enroll in a clinical trial. These studies test new treatments that aren’t yet available to the public. Ask your doctor how to find a trial that matches your cancer type.

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