Most spinal tumors are metastases – tumors that have spread from cancer in another part of the patient’s body, usually breast, prostate or lung cancer.
What are the symptoms?
Symptoms occur when spinal tumors compress nerves or weaken the vertebral structure. Incontinence and decreased sensation in the buttocks are considered warning signs of spinal cord compression from a tumor. Back pain in patients with a known malignancy may prompt a bone scan to confirm a spinal metastasis.
What are the treatment options?
The primary goal in treating spinal metastases is pain relief and preventing neurological deterioration. These tumors can be treated with medication, surgery, conventional radiation therapy or radiosurgery.
Steroids can help reduce inflammation around a spinal tumor. This doesn’t affect the tumor, but reducing inflammation can decrease the overall volume of the mass pressing on the spinal cord.
For spinal tumor patients with severe spinal cord compression or a condition known as impending vertebral collapse, doctors generally recommend open surgery followed by bone repair with metal hardware, and fusion is generally indicated.
Conventional radiation therapy
Conventional radiation therapy is the standard treatment for painful metastases affecting the spinal column. It carries several disadvantages, including side effects within the healthy tissue around the tumor and a longer course of treatment compared to CyberKnife radiosurgery. Certain types of metastatic tumors also respond poorly to standard radiation therapy, yet they’re well controlled with more aggressive CyberKnife treatment.
The CyberKnife treats spinal tumors aggressively with high-dose radiation that doesn’t require a rigid metal frame attached to the patient’s skeleton like other radiosurgical systems. This is made possible by an advanced imaging system that tracks the tumor location during treatment procedures.
For tumors in the upper neck area, the CyberKnife tracks the location using the patient’s skull anatomy as a reference point. Other patients may need fiducials, small metal markers anchored to bones in the neck, back or spine, placed in a brief outpatient procedure. The markers allow the CyberKnife to pinpoint the tumor position during treatments, compensating for small movements like patient breathing. This also makes CyberKnife treatment much more comfortable than treatment with other radiosurgical systems.
The CyberKnife usually can treat most types of spinal tumors if they’re relatively compact and not too large – a volume of 150 cubic centimeters or less. It also can treat both benign and malignant spinal tumors. Treatment of spinal metastases also depends on the type of primary cancer, the duration of neurological symptoms and the tumor location.
Generally, radiosurgery is safest and easiest with tumors not treated previously with conventional radiation therapy. However, the CyberKnife uses contoured radiation beams that limit exposure to the tumor site. As a result, the CyberKnife produces good results with spinal tumors, even if they were previously irradiated.
In addition, the spinal cord has a limited radiation tolerance. Therefore, the dosage amounts used with conventional radiation therapy usually limit this form of treatment to cases in which surgery isn’t feasible. Spinal radiosurgery with the CyberKnife, however, appears to offer an effective alternative to surgery and conventional radiation for patients with certain kinds of benign lesions.
Malignant spinal tumors like myeloma, lymphoma, osteosarcoma and Ewing sarcoma are generally treated with a combination of chemotherapy and conventional radiation therapy. With isolated tumors or tumors that regrow after conventional treatment, radiosurgery can be very effective.
Low-grade malignant spinal tumors like chondrosarcoma, hemangioblastoma and ependymoma are typically treated with surgery. CyberKnife can be effective for these tumors in certain cases. CyberKnife also can be affective for patients with a higher risk of developing multiple spinal tumors like those with a genetic condition known as von Hippel Lindau’s disease or other tumor types, depending on clinical circumstances.
What is the CyberKnife treatment process for spinal tumors?
Patients treated for tumors in the neck or spine may need a mesh facemask or body mold made of soft material that reduces movement during CyberKnife treatment. The fitting process is painless. For lesions farther down the spinal column, doctors implant small metal markers known as fiducials into the spine that enable the CyberKnife’s precision aiming. Implanting markers requires surgery in an operating room with either general or local anesthesia, though it’s usually an outpatient procedure with minimal pain. Between four and six markers are placed around the lesion through small punctures in the skin.
A CT scan is performed while patients lie on their back with the mask to keep the head and neck still. Sometimes, contrast – a special dye – is used to create better imaging. If patients are allergic to the contrast or can’t receive it for other reasons, they may get a so-called non-enhanced CT scan.
A surgeon, radiation oncologist and radiation physicist work with patients to develop a treatment plan. CyberKnife spinal treatments are outpatient procedures that don’t require anesthesia and usually take an hour or two. Patients who experience pain while lying on their back are asked to take their pain medication before each CyberKnife treatment.
There are no direct side effects from the treatment itself. Occasionally, patients who receive treatment to their lower back may experience mild nausea, because the radiation passes through the intestines. Those patients may be given anti-nausea medicine before treatment.
Patients can return home immediately after treatment, and there is no recovery time. Occasionally, treatments are fractionated, meaning they’re spread over a few days so a larger radiation dose can be used. The physician team decides whether to fractionate based on individual cases.