Spinal tumors include a wide range of abnormal growths that occur in and around the spinal column. These tumors are rarer than brain tumors and are classified by location and the type of tissue involved. Many cancers that arise outside of the spine or spinal cord can travel to the area surrounding the spine. These tumors can travel to the spinal bones (vertebrae), causing pain and, on occasion, collapse of the vertebrae. These tumors can also affect the soft tissues and spaces surrounding the spine (the epidural space) and compress the spinal cord or the spinal nerves, resulting in pain, paralysis, sensory loss, and/or loss of bowel or bladder control. All of these areas of tumor spread are termed “metastatic disease of the spine” or “spinal metastases.” Even though the cancer now affects the spine, the cells are still from the primary tumor (breast, lung, colon, etc.) and therefore the treatment of spinal metastases depends on the type of tumor, number of tumors and the amount of systemic disease.
Spinal tumors are classified according to their location in the spine; Extradural (vertebral) tumors, Intradural-extramedullary tumors, Intramedullary tumors.
These tumors occur in the vertebral column, and grow either from the bone or disc elements of the spine. They typically occur in younger adults. Osteogenic sarcoma (osteosarcoma) is the most common malignant bone tumor. Most primary spinal tumors are quite rare and usually grow slowly.
Most often, spinal tumors metastasize (spread) from cancer in another area of the body (see Figure 1). These tumors usually produce pain that does not get better with rest, may be worse at night, and is often accompanied by other signs of serious illness (such as weight loss, fever/chills/shakes, and nausea or vomiting).
Intradural-Extramedullary (inside the dura) tumors grow within the spinal canal (under the membrane that covers the spinal cord) but outside of the nerves. Usually these tumors are benign and slow growing. However, they can cause symptoms of pain and weakness. Most of these spinal tumors are:
- Meningiomas that occur in the membranes surrounding the spinal cord and are usually benign but may be malignant. These tumors are more common in middle age and elderly women.
- Nerve sheath tumors (schwannomas and neurofibromas) that arise from the nerve roots which come off the spinal cord. Again, this type of tumor is usually benign and slow growing, and it may be years before any neurological problems occur.
Intramedullary tumors grow from inside the spinal cord or inside the individual nerves and often arise from the cells that provide physical support and insulation for the nervous system (glial cells). These tumors occur most often in the cervical spine (neck). They tend to be benign, but surgery to remove the tumor may be difficult. The two most common types of intramedullary tumors are astrocytomas and ependymomas.
The symptoms caused by a spinal tumor depend on many factors, including the tumor location, how quickly it grows with invasion into other spinal elements, spinal cord and nerve involvement, and it might also effect on spinal stability.
Back and leg pain may be the initial symptoms of spinal tumors. Some spinal tumors may cause leg or arm weakness and numbness, sciatica, partial paralysis, clumsiness, spasticity, bowel or bladder problems, or spinal deformity. Symptoms may develop gradually or appear suddenly, and symptoms usually worsen unless treated. The symptoms can be detailed as:
- Pain in the neck or back, followed by neurological problems (such as weakness or numbness of the arms or legs or a change in normal bowel or bladder habits) is most common
- Focal spine pain that is worse in the morning
- Pain that is severe when there is direct manipulation or compression of the affected area of the spine
- Pain that does not diminish with rest, and pain that may be worse at night than during the day
- Back pain along with constitutional symptoms, such as loss of appetite, unplanned weight loss, nausea, vomiting, or fever, chills or shakes.
Treatment & management
In most cases, spinal tumor surgery is a treatment of last resort, i.e. other non-surgical treatments such as radiation (Chemotherapy is not proven to be effective in spinal tumors), have already been tried and often will continue to be used in the patient’s treatment regimen
The primary goals in surgery are to reduce pain caused by the spinal tumor, restore or preserve neurologic function, and provide spinal stability. The spinal tumor may be approached surgically from the front (anterior) or back (posterior) of the body.
Surgery may include tumor resection (partial removal) or excision (complete removal) through different approaches; In general, spinal tumor procedures include:
In Minimal Invasive approaches to tumor surgery, the tumor can be indirectly scraped and removed (e.g., percutaneous curettage). Minimal invasive surgical procedures involve the passage of substances and/or instruments, such as a needle, wires, drills, or catheters through a small incision. The removed section usually requires cement being injected into the vertebra for stabilizing the vertebra.
If there are neurological symptoms, an open procedure is usually necessary where a larger incision is made to remove tissue pressing against the spinal cord and nerves.
The ultimate goal of radiation therapy is to destroy a spinal tumor. Radiation is also used to shrink a tumor before or after spine surgery and to relieve tumor-related pain.
A careful and thoughtful assessment is important because there are many types of radiation and delivery methods. Therefore, careful planning based on the assessment is essential to a good radiation therapy outcome. Sometimes radiation therapy is combined with a radiosensitizer. A radiosensitizer is a drug that makes cancer cells hypersensitive to radiation’s effects.
External Radiation Therapy
External radiation therapy is the most common and is delivered to the patient from the outside of his/her body through radiation machine. In other words, radiation is directed at a specific area of the body or target. This type of therapy is often provided on an outpatient basis.
Internal Radiation Therapy (or Interstitial Radiation Therapy)
This kind of radiation therapy delivers radiation by means of sealed implants inserted near the tumor. This type of therapy is more common in cases of neck cancer. This therapy usually requires hospitalization because the patient is radioactive and special precautions are taken to protect hospital staff and visitors.
Palliative Radiation Therapy
Palliative care is directed to improving symptoms associated with incurable cancer. This is delivered to help reduce pain and symptoms from metastatic cancer (cancer that has spread.
Prophylactic Radiation Therapy
This is delivered to cancer-free areas to help prevent the spread (metastasis) of cancer cells. This type of radiation is not suitable for all patients or types of cancerous spinal tumors.
Combining Drugs with Radiation
As mentioned earlier, radiosensitizers are drugs that can help make cancer cells more receptive to the goals of radiation. Sometimes these drugs are called hypoxic radiosensitizers. Basically, these drugs reduce the amount of oxygen (hypoxicity) cancer cells can absorb. Since oxygen is essential to cell repair, hypoxicity contributes to cancer cell death.
To protect non-cancerous cells from radiation’s harmful effects, radioprotector drugs may be administered. Currently, the only drug approved by the US Food and Drug Administration (FDA) is amifostine (brand name Ethyol). It is administered intravenously to prevent dry mouth and protect the saliva-producing glands in patients with neck cancer. Currently, existing drugs are under investigation for other applications in radiation therapy. New drug research is also being conducted.