Metastatic Tumors of the Spine
Spine metastases imply that a tumor of an origin distant from the site affected has traveled and invaded a portion of the spine. These lesions represent a continuum of the disease process that affects patients with cancer. The diagnosis and treatment of spinal metastases requires a highly coordinated effort of multiple health care providers including the spine surgeon, internist or primary care physician, oncologist, radiation oncologist, orthotist and other oncologic health care providers such as social services, pastoral care and other ancillary staff.
HOW DO TUMORS SPREAD TO THE SPINE?
Tumors can spread or metastasize through various mechanisms. Tumors that spread to the spine usually do so by gaining access to the bodyís blood system and often get lodged into the vertebral body (see anatomy). Tumors from the breast, prostate or lung often metastasize via Batsonís plexus. This plexus is a group of veins that are located along the vertebral column, and because of their flow mechanics have a high predilection to trap tumor cells. Another way tumor cells travel is by invading whatever is next to the tumor called direct extension. Either way, in order for the tumor cells to survive there has to be a blood supply.
WHAT IS THE CLINICAL MANIFESTATION OF A SPINE
Pain is by far the most common presentation. Pain occurs because of several different factors: 1) tumor growth leading to bone pain- a deep and relentless ache. 2) A fracture through the tumor. 3) Instability of the spine because of tumor invasion and 4) compression of nerve roots or of the spinal cord.
The surgeons interview and physical exam will help differentiate these different origins of pain.
The neurologic exam is one of the most important elements of the exam as it is a key factor in predicting the prognosis and outcome after diagnosis with a metastatic spine tumor. Of those patients with the ability to walk at the time of diagnosis, 90% retain that ability. Patients with significant weakness on the other hand frequently do not regain their function and those who present with paraplegia only find the ability to walk again 30% of the time. The timing of onset also plays an important role. Of those with onset of weakness within a short period of time (days) have a much worse prognosis than those who develop this problem over several weeks or even months.
INITIAL COMPLAINTS WITH SPINE TUMORS
Pain and weakness
Pain and mass
Weakness and pain
Mass and pain
IF I HAVE A KNOWN TUMOR AND AM NEWLY DIAGNOSED WITH A SPINE TUMOR WHAT SHOULD I EXPECT AS FAR AS TESTING?
It is important that the communication lines are open between all physicians involved! A baseline of blood work should be obtained to check blood cell levels and ensure that there isnít another reason to have this lesion (such as infection). The entire spine should then be imaged including x-rays and MRI. The x-rays give a good overall picture and idea of spine alignment. The MRI is very useful for characterizing the tumor, detecting any neurologic involvement, or cord compression. It also allows the surgeon to assess the effect the tumor is having on the tissues surrounding it and determining if surgery is a treatment option. If surgery is to be performed then a CT is often obtained to further characterize the bony anatomy of the spine, which is in far greater detail with a CT scan. Finally bone scans can be useful in differentiating between tumors and infection, as well as giving a generalized view of other organs or bones that may have a metastatic lesion.
WHAT ARE THE TREATMENT OPTIONS FOR
METASTATIC SPINE LESIONS?
When pain is tolerable, the spine is stable and there is no neurologic involvement then radiation therapy should be the main mode of treatment. A radiation oncologist will evaluate you and see if the tumor is amenable to radiation treatment.
The indications to operate are the following:
- Life expectancy > 3 months
- The need for a tissue diagnosis
- Spine instability- when the tumor has involved so much of the spine that it is now unstable causing pain, and the potential for further damage under circumstances that a normal spine would tolerate
- Neurologic deficit- if nerve pain is the only factor then radiation is preferred. If there is noticeable weakness then this is an indication to operate. Similarly if the spinal cord is being compressed enough to cause clinical symptoms then surgery should be advocated.
- Fracture- bone that is invaded by tumor is often significantly weakened and can result in a break (aka fracture). The fracture can be simple as in a compression fracture or more complex such as a burst fracture causing spinal canal compromise and resulting in spine deformity (scoliosis or kyphosis). In these instances surgery is usually employed
WHAT SURGERY IS RIGHT FOR SPINE METASTASIS
If there is a simple compression fracture then frequently all that is needed is stabilization with cement in the form of kyphoplasty or vertebroplasty. This is a minimally invasive procedure that creates a cavity in the fracture and fills the void with cement.
If a more complex fracture results, or there is significant amount of tumor impinging the nerves or spinal cord then a decompression and fusion is usually indicated. This can be done through traditional open approaches (approaching the spine from both the front, anterior, and from the back, posterior), or through less invasive approaches. The San Diego Center for Spinal Disorders is dedicated to developing and practicing spine surgery in the least invasive way possible. Please review the case examples for the various treatments that exist. The surgery usually involves removing the bone where the tumor lives followed by using metal plates and screws to reconstruct the spine and stabilize it. The removal of the tumor and decompression usually result in alleviation of pain and the hopes to improve neurologic function as well.
WHAT ARE THE COMPLICATIONS OF SURGERY?
Complications vary according to the type of procedure and can be quite insignificant or result in permanent neurologic injury or even death. The less invasive the surgery the lower the complication rate. Infection remains a problem, primarily because of malnutrition and a poor immune system secondary to the cancer. Medical complications associated with spine surgery are more common than elective spine surgery and include urinary tract infections, constipation, blood clots, strokes, blood clots to lungs, and heart attack.
The vast majority of metastatic spine tumors can be treated without surgery. This, however, requires a highly coordinated effort among spine surgeons, other physicians and ancillary/support staff. Surgery, when indicated, usually results in predictable outcomes and can sometimes be accomplished by minimally invasive spine surgery when appropriate.
The San Diego Center for Spinal Disorders
and its staff is dedicated to the care of this special group of patients and
prides itself in communicating with the oncology team and offering new and
innovative techniques in treating spine tumors.