Tests for Bone Cancer

Primary bone cancers are usually found when signs or symptoms a person is having prompt them to visit a doctor.

The information here focuses on primary bone cancers (cancers that start in bones) that most often are seen in adults. Information on Osteosarcoma, Ewing Tumors (Ewing sarcomas), and Bone Metastasis is covered separately.

Symptoms and the results of physical exams and imaging tests might suggest that a person has bone cancer. But in most cases, doctors need to confirm this by taking and testing a tissue or cell sample (a procedure known as a biopsy).

It’s important for doctors to distinguish primary bone cancers from cancers that have spread to the bones from other parts of the body (bone metastasis), as well as from bone tumors that are benign (not cancer) and from other types of bone problems. These conditions might need different types of treatment.

Accurate diagnosis of a bone tumor often depends on combining information about which bone and what part of the bone is affected, how it looks on imaging tests, and what the tumor cells look like under a microscope.

If a bone cancer is found, other tests might then be needed to learn more about it.

Medical history and physical exam

If a person has signs or symptoms that suggest they might have a bone tumor, the doctor will want to take a complete medical history to find out more about the symptoms.

A physical exam can sometimes provide information about a possible tumor. For example, the doctor may be able to see or feel an abnormal mass.

The doctor may also look for problems in other parts of the body. When adults have cancer in the bones, it’s most often the result of cancer that started somewhere else and then spread to the bones (bone metastasis).

After the exam, if the doctor suspects it could be bone cancer (or another type of bone tumor), more tests will be done. These might include imaging tests, biopsies, and/or lab tests.

Imaging tests

Imaging tests use x-rays, magnetic fields, or radioactive substances to create pictures of the inside of the body. Imaging tests might be done for a number of reasons, including:

• To help find out if a suspicious area might be cancer
• To help determine if a cancer might have started in another part of the body
• To learn how far cancer has spread
• To help determine if treatment is working
• To look for signs that the cancer might have come back

People who have or might have bone cancer will have one or more of these tests. For more information on these tests, see Imaging (Radiology) Tests for Cancer.

X-rays

An x-ray of the bone is often the first test done if some type of bone tumor is suspected. Tumors might look “ragged” instead of solid on an x-ray, or they might look like a hole in the bone. Sometimes doctors can see a tumor that might extend into nearby tissues (such as muscle or fat).

Doctors might strongly suspect an abnormal area is a bone cancer by the way it appears on an x-ray, but usually a biopsy (described below) is needed to tell for sure.

Adults with bone tumors might have a chest x-ray done to see if the cancer has spread to the lungs. But this test isn't needed if a chest CT scan (discussed below) has been done.

Magnetic resonance imaging (MRI)

MRI scans create detailed images of the inside of the body using radio waves and strong magnets instead of x-rays, so no radiation is involved. A contrast material called gadolinium is often injected into a vein before the scan to better see details.

An MRI is often done to get a more detailed look at an abnormal area of bone seen on an x-ray. MRIs can usually show if it’s likely to be a tumor, an infection, or some type of bone damage from another cause.

MRIs can help determine the exact extent of a tumor, as they can show the marrow inside bones and the soft tissues around the tumor, including nearby blood vessels and nerves. MRIs can also show any small bone tumors several inches away from the main tumor (called skip metastases). Knowing the extent of tumor is very important when planning surgery.

Computed tomography (CT) scan

A CT scan combines many x-ray pictures to make detailed cross-sectional images of parts of the body. 

CT scans aren’t usually as helpful as MRIs in showing the detail in and around bone tumors. But they are often done to look for possible cancer spread in other parts of the body, such as the lungs, liver, or other organs.

CT scans can also be used to guide a biopsy needle into a tumor (a CT-guided needle biopsy). For this test, you stay on the CT scanning table while the doctor moves a biopsy needle toward the tumor. CT scans are repeated until the tip of the needle is within the mass. (See Needle biopsy below.)

Bone scan

A bone scan can show if a cancer has spread to other bones, and is often part of the workup for people with bone cancer. This test is useful because it can show the entire skeleton at once. A positron emission tomography (PET) scan, described below, can often provide similar information, so a bone scan might not be needed if a PET scan is done.

For this test, a small amount of low-level radioactive material is injected into the blood and travels to the bones. A special camera that can detect the radioactivity then creates a picture of the skeleton.

Areas of active bone changes attract the radioactivity and appear as “hot spots” on the skeleton. Hot spots may suggest areas of cancer, but other bone diseases can also cause the same pattern. To make an accurate diagnosis, other tests such as plain x-rays, MRI scans, or even a bone biopsy might be needed.

Positron emission tomography (PET or PET scan)

For a PET scan, a form of radioactive sugar (known as FDG) is injected into the blood. Because cancer cells in the body are growing quickly, they absorb large amounts of the sugar. A special camera then creates a picture of areas of radioactivity in the body. The picture is not detailed like a CT or MRI scan, but it provides useful information about the whole body.

PET scans can help show the spread of bone cancer to the lungs, other bones, or other parts of the body. They can also be used to see how well the cancer is responding to treatment.

Many machines can do a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed appearance of that area on the CT scan.

Biopsy

The results of imaging tests might strongly suggest that a person has bone cancer, but a biopsy (removing some of the abnormal area and checking it under a microscope and with other lab testing) is usually the only way to be certain.

If the tumor is most likely a primary bone cancer, it’s very important that the biopsy is done by doctors experienced in treating bone tumors. Whenever possible, the biopsy and surgical treatment should be planned together, and the same doctor should do both. Proper planning of the biopsy can help prevent later complications and might reduce the amount of surgery needed later on.

Sometimes the wrong kind of biopsy can make it hard for the surgeon to later remove all of the cancer, which might then require more extensive surgery. It might also increase the risk of the cancer spreading.

The type of biopsy done is based on whether the tumor looks benign (not cancer) or malignant (cancer) and exactly what type of tumor it most likely is (based on imaging tests, the patient’s age, and where the tumor is). Some kinds of bone tumors can be diagnosed from needle biopsy samples, but larger samples (from a surgical biopsy) are often needed to diagnose other types. Plans to remove the entire tumor during the biopsy will also impact the type of biopsy done.

Needle biopsy

For these biopsies, the doctor uses a hollow needle to remove a small cylinder of tissue from the tumor. The biopsy is usually done with local anesthesia, where numbing medicine is injected into the skin and other tissues over the biopsy site. In some cases, the patient might need sedation or general anesthesia (where the patient is asleep).

Often, the doctor can aim the needle by feeling the suspicious area if it's near the surface of the body. If the tumor can’t be felt because it's too deep, the doctor can guide the needle into the tumor using an imaging test such as an ultrasound or CT scan. These types of image-guided biopsies are usually done by a doctor who is an interventional radiologist.

There are 2 types of needle biopsies:

• A core needle biopsy uses a large needle to remove a cylinder of tissue. This is the most common type of needle biopsy used for bone tumors.
• A fine needle aspiration (FNA) biopsy uses a very thin needle on the end of a syringe to suck out a small amount of fluid and some cells from the tumor. This type of biopsy is less likely to be helpful for bone tumors, as the smaller needle might not be able to get through the bone. And even if it can be done, it might not remove enough of a sample for testing. But FNA can sometimes be useful for checking abnormal areas in other parts of the body for cancer cells.

Surgical (open) biopsy

For this type of biopsy, a doctor (typically an orthopedic surgeon) cuts through the skin to reach the tumor. If only a piece of it is removed, it is called an incisional biopsy. If the entire tumor is removed (not just a small piece), it's called an excisional biopsy.

These biopsies are often done in an operating room with the patient under general anesthesia (in a deep sleep). They can also be done using a nerve block, which numbs a large area of the body.

Again, it’s important that the biopsy is done by an expert in bone tumors, or it could result in problems later on. For example, if the tumor is on the arm or leg and the biopsy isn’t done properly, it might lower the chances of saving the limb. If possible, the incision for the biopsy should be lengthwise along the arm or leg because this is the way the incision will be made during the operation to remove the cancer. The entire scar of the original biopsy will also most likely need to be removed, so making the biopsy incision this way means less tissue will need to be removed later on.

Lab tests

Testing the biopsy samples

All samples removed by biopsy are sent to a pathologist (a doctor specializing in lab tests) to be looked at with a microscope. If cancer cells are seen, other types of lab tests might also be done to learn more about the exact type of cancer. 

The pathologist will also assign the cancer a grade, which is a measure of how quickly it is likely to grow and spread, based on how the tumor cells look. Cancers that look somewhat like normal bone tissue are described as low grade (and tend to grow more slowly), while those that look very abnormal are called high grade. For more on grading, see Bone Cancer Stages.

Blood tests

Blood tests are not needed to diagnose bone cancer, but they may be helpful once a diagnosis is made. For example, high levels of chemicals in the blood such as alkaline phosphatase and lactate dehydrogenase (LDH) can suggest that the cancer may be more advanced.

Other tests such as blood cell counts and blood chemistry tests are done before surgery and other treatments to get a sense of a person’s overall health. These tests can also be used to monitor the person’s health while they are getting treatments such as chemotherapy.