Patients' Guide to Spinal Cancer

Understanding Spinal Osteosarcomas

Key facts about the most common type of bone cancer

Osteosarcoma, also known as osteogenic sarcoma, is the most common type of cancer that develops in bone. Most osteosarcoma tumors develop in the bones around the knee and upper arm, but this disease can develop in any bone—including the bones of your spine.

Anatomical illustration of L3-L4; elements labeledThe above illustrates a section of the lumbar (low back) spine; specifically L3-L4.

In general, spinal tumors are rare and only 3–5 percent of all osteosarcomas occur in the back or neck. As it relates to the spine, osteosarcoma is a type of primary spinal tumor. Primary means that a tumor lives at the site where it originated, as opposed to a tumor that developed elsewhere in your body then metastasized, or spread, to a different location.

Though it’s the most common type of primary bone cancer, osteosarcoma is still a rare disease. Each year, about 800 new cases of osteosarcoma are diagnosed in the United States. About half of those are in children and adolescents.

Most osteosarcomas occur in people between 10 and 30 years of age, with teens developing the disease more than any other age group. While osteosarcoma in the arms and legs tends to affect children and teens, spinal osteosarcoma occurs more often in the young adults.

What Is Osteosarcoma?
Osteosarcoma weakens bone. In healthy bone, cells called osteoblasts continually lay strong, new bone to maintain the life-long health of your bones. The tumor cells in osteosarcoma work in a similar fashion to osteoblasts, but the bone created by the cancerous cells is much weaker and not fully formed.

In young people, osteosarcoma usually develops in the long bones such as the arms and legs that experience rapid growth. However, older adults who develop the disease often have tumors elsewhere, including the pelvis and spine. The most common areas of the spine affected by osteosarcoma are the sacrum (between the hips), followed by the lumbar (low back) and thoracic (mid-back) regions.

What Causes Osteosarcoma?
Scientists don’t fully understand what causes most osteosarcomas, but they have found that some people with certain inherited DNA changes are more prone to developing this cancer.

Those at higher risk of developing spinal osteosarcoma include people:

  • Who have undergone radiation therapy for another cancer
  • With specific noncancerous bone diseases, namely Paget disease and hereditary multiple osteochondromas
  • With specific rare, cancer syndromes caused by inherited DNA mutations, including inherited retinoblastoma, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, Bloom syndrome, Werner syndrome, and Diamond-Blackfan anemia

While some people are at higher risk for developing osteosarcoma due to inherited gene changes, the majority of osteosarcomas are not caused by them. Scientists have found that osteosarcomas often develop due to sporadic gene changes that happen after a person is born, so they are not inherited.

DNA changes that occur throughout a person’s life often have no obvious cause. Cells can make mistakes while reproducing new cells, and this can affect the new cells’ DNA. These genetic errors are more likely when cells divide quickly, and osteosarcoma often occurs during periods of rapid bone growth.

While scientists have made great strides in understanding the role of gene mutations in osteosarcoma, they are still researching the underlying cause of this cancer.

Diagnosing Spinal Osteosarcoma
As with all cancers, achieving an early diagnosis is key to successfully managing spinal osteosarcoma.

Imaging tests are important if you have a spinal osteosarcoma. Your doctor may use x-rays, CT scans, bone scans, MRI, or other imaging technology to identify the spinal tumor and determine if it has metastasized, or spread to other areas of the body.

While imaging can help doctors see abnormalities in your spine, biopsies are the ultimate diagnostic tool to confirm spinal osteosarcoma. There are two categories of biopsy: needle and surgical.

During a needle biopsy, the doctor extracts a small sample of the spinal tumor with a hollow needle. The procedure is typically done using a local numbing agent, though your doctor may have you sedated or under general anesthesia.

In a surgical biopsy, the surgeon removes a sample of the tumor through a skin incision. Surgical biopsy is performed under general anesthesia.

The results of the biopsy will help your doctor determine whether the osteosarcoma is high grade, intermediate grade, or low grade. Knowing the grade of the spinal tumor helps your doctor understand how advanced the cancer is and how likely it is to spread (if it hasn’t already).

Symptoms of Spinal Osteosarcoma
Almost all people with spinal osteosarcoma will experience back pain at the site of the tumor, and some may have weakness, sensory loss, or loss of bowel or bladder control if the tumor is in the pelvis or base of the spine (lumbar, low back) as the tumor can lead to nerve compression at the spinal canal or along the nerve tracts. Swelling at the tumor site is also common, and the joints near the tumor may feel stiff and inflamed.

Arguably, the most serious potential symptom of osteosarcoma is fracture, though this is rare. While osteosarcoma weakens the bone it grows in, the bone typically stays intact. However, one form of osteosarcoma—known as telangiectatic osteosarcoma—can develop in the spine and weaken bones more than other types of osteosarcoma, making it more likely to cause bone breakage.

Your team of doctors will discuss with you the best way to manage symptoms and work with you to develop a treatment plan. Different types of therapies are available to treat osteosarcoma in the spine.

To learn about Dr. Hsieh's practice, click here.

Updated on: 02/02/17
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Spinal Cancer: What You Should Know
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Spinal Cancer: What You Should Know

SpineUniverse spoke with Ali A. Baaj, MD, who answers questions about spinal cancer; what it is, who is at risk, and how spinal cancer is diagnosed and treated.
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