Spinal Cord Astrocytomas
ASTROCYTOMAS ARE THE MOST COMMON spine tumors in the family of tumors called gliomas. Astrocytoma of the spinal cord is a rare tumor that grows from star-shaped support cells of the nervous system, called astrocytes. In general, they are not cancerous. But they do require close monitoring because they can cause dysfunction of the spinal cord. A very small percentage can behave aggressively.
According to medically based research, there are four grades in which spinal cord astrocytomas are classified:
- Grade I – These low-grade tumors, such as pilocytic astrocytoma, can be cured by surgical removal. They do not invade into other structures but can cause symptoms through mass effect if they grow large enough. These low-grade astrocytomas tend to be in children.
- Grade II – These are diffuse, infiltrating spine tumors that generally grow slowly. They can be effectively managed long-term but must be watched closely as they can turn more aggressive.
- Grade III – Also known as anaplastic astrocytoma, these are more aggressive tumors that are treated as cancerous.
- Grade IV – These high-grade astrocytomas are the most aggressive and rapidly growing type of cancerous astrocytoma.
Lower grade astrocytomas (Grade I and II) are typically assigned to slow-growing tumors that are benign, whereas higher grade (Grade III and IV) astrocytomas indicate a fast-growing tumor that is malignant. These malignant tumors tend to invade surrounding healthy tissue, causing further damage. Lower-grade tumors can progress to become higher grade.
Spinal astrocytomas are also classified by their location:
Astrocytomas that grow in the brainstem are known as brainstem gliomas. These astrocytomas are located toward the base of the patient’s skull and above the back of the neck where the brainstem helps coordinate functions essential for life, including breathing and heart rate. Brainstem gliomas are usually high grade, but they can be any grade and they occur mostly in children and young adults.
Tumors that grow in the part of the brain called the pineal gland are referred to as pineal astrocytic tumors. This gland is a pea-sized region that produces the hormone melatonin, which regulates the sleeping and waking cycle. Pineal astrocytic tumors can be any grade.
Some astrocytomas contain astrocytes and another type of glial cell, oligodendrocytes. These tumors are called mixed gliomas, or oligoastrocytomas.
Symptoms of Spinal Cord Astrocytomas
Symptoms vary depending on the location of the spinal cord tumor and can include:
- Persistent back pain
- Numbness and other sensory changes
- Muscle weakness/spasms on one or both sides of the body
- Loss of bladder and/or bowel control
- Loss of balance and gait instability (ataxia)
Risk Factors of Spinal Cord Astrocytomas
An astrocytoma develops when a genetic mutation causes an astrocyte, or support cell of the nervous system, to grow in a disordered manner. In a benign or low-grade astrocytoma, growth is slow, but the resulting mass effect on surrounding tissues can cause symptoms. If additional mutations occur, the tumor cells learn how to invade and infiltrate into surrounding tissues, in a cancerous transformation.
As in many cases with primary spinal neoplasms, the exact cause of these mutations is unknown. Several risk factors have been identified:
- Age. In general, astrocytomas of the spine are more common in children and young adults, and within this population, tend to be more benign. Aggressively growing tumors are more common in adults over 35 years old.
- Radiation exposure. Previous exposure to ionizing radiation is a significant factor in the development of spinal astrocytoma. Ionizing radiation includes X-rays, radiation treatments, and nuclear contamination. There is no evidence that electromagnetic radiation from electrical power lines, microwaves, or cell phones is connected to astrocytoma formation in the spinal cord.
- Genetic factors. There is limited evidence of genetic components in the development of astrocytoma of the spine.
Diagnosis of Spinal Cord Astrocytomas
The diagnosis begins with a thorough evaluation by a spine expert, including a complete history, and neurological exam that identifies even subtle deficits. When performed well, the history and physical will identify which part of the spine is involved.
MRI is the test of choice to confirm a diagnosis of astrocytoma, and to give a clear anatomical picture of tumor location, size, and morphology.
When tumor location is identified, and involvement of surrounding structures analyzed, the patient will likely be scheduled for the tissue biopsy, which could be performed separately or combined with tumor resection. A biopsy is a surgical procedure, performed under anesthesia in an operating room, that allows the surgeon to collect a small sample of the affected tissue.
Tissue collected during biopsy will be sent to the laboratory for evaluation under a microscope by a neuropathologist. Based upon results, a precise diagnosis will be made as to whether the tumor is benign (non-cancerous) or malignant (cancerous). In addition, the biopsy will identify the cell of origin, and grade of the tumor. All of these factors determine the treatment plan and prognosis.
Follow-up and Prognosis
The most important factor for prognosis is tumor grade. Low grade tumors, such as pilocytic astrocytoma, can be cured. On the other end of the spectrum, high grade, aggressive tumors such as glioblastoma multiforme of the brain cannot be cured, but modern treatment techniques can allow for extended spinal cord functioning and quality of life. A patient’s prognosis should be a part of the pre-/post-treatment discussions with the medical team.
Patients undergoing treatment will be under close observation by the medical team, with scheduled follow-up visits and MRI scanning.
Depending on the extent of the tumor resection and postoperative course, one may acquire some deficits, such as balance, motor, sensory changes, etc. In that case, occupational/physical therapy specialists will be involved to speed recovery and assist in regaining normal function.
Treatment of Spinal Cord Astrocytomas
Treatment of spinal astrocytomas depends on the location, size, grade of tumor, age, overall health state, and past medical history.
Watchful waiting with or without radiation therapy could be a treatment option for low-grade astrocytomas, that show no signs of growth or spread.
For large or aggressive tumors, treatment is maximal safe surgical resection of the tumor, without causing damage to the spinal cord. The goal is always to preserve spinal cord function. Although incomplete resection will not cure the condition, it can provide symptom relief, and can slow progression of disease.
A neurosurgeon uses several tools to maximize the safety and efficacy of tumor removal, including lasers, and intraoperative ultrasound. Side effects of surgery may include infection, bleeding, cerebrospinal fluid leak, weakness, sensory loss, imbalance, and tumor regrowth.
In general, surgery is followed by a combination of chemotherapy and radiation therapy.
Radiation Therapy (RT) is widely used:
- To shrink spinal cord tumors that do not need to be surgically removed
- To shrink the tumor before excision to ease surgical removal
- To kill residual tumor cells after incomplete resection.
Radiation therapy is performed by a radiation oncologist, who uses a special machine that precisely focuses a beam of high-energy particles (X-Rays or protons) on the tumor.
Radiation therapy can produce some side effects as well, such as nausea, headaches, tiredness, loss of appetite, as well as red, sore, and inflamed skin. There can also be numbness, tingling, weakness, or imbalance.
Learn More by Consulting Top Neurosurgeons
The board-certified neurosurgeons at Centers for Neurosurgery, Spine & Orthopedics understand that a spine tumor diagnosis will drastically impact a patient’s life, thus compassionately guide and advise a patient and their loved ones. CNSO offers multiple convenient locations spanning northern New Jersey, including Bergen, Passaic, Essex, Morris, and Hudson counties. Learn how the doctors at CNSO can alleviate spine pain by requesting an appointment today.