Staging is a way of describing where a tumour is located, if or where it has spread, and whether it is affecting other parts of the body. Several types of childhood CNS tumours can spread through the spinal fluid that surrounds the brain and the spine.
Doctors also describe astrocytoma by its grade.
The grade describes how much tumour cells look like healthy cells when viewed under a microscope.
The doctor compares the tumour tissue with healthy tissue. Healthy tissue usually contains many different types of cells grouped together. If the tumour tissue looks similar to healthy tissue and has different cell groupings, it is called “differentiated” or a “low-grade tumour.” If the tumour tissue looks very different from healthy tissue, it is called “poorly differentiated” or a “high-grade tumour.” The tumour’s grade may help the doctor predict how quickly it will spread. In general, the lower the tumour’s grade, the better the prognosis.
Grades of Astrocytoma Brain Tumor:
Grade I – Pilocytic Astrocytoma
Also called Juvenile Pilocytic Astrocytoma (JPA). Pilocytic astrocytoma is a benign brain tumour that arises from astrocytes, the supportive cells in the nervous system. Normally, astrocytes are responsible for a variety of roles, including providing nutrients to neurons, maintaining the blood-brain barrier, and modulating neurotransmission.
For most patients, the cause of pilocytic astrocytoma is unknown. however, there are a few rare, genetic conditions that may increase a patient’s chance of developing pilocytic astrocytoma.
Symptoms- headaches, fatigue, nausea, vomiting, weight gain or loss, difficulties with balancing and walking and premature puberty.
- Grows in the cerebrum, optic nerve pathways, brain stem and cerebellum.
- Accounts for two percent of all brain tumors.
- Slow growing, with relatively well-defined borders.
- Occurs most often in children and teens.
Individuals with very slow-growing tumours where complete surgical removal by stereotactic surgery is possible may experience total remission. Surgery is the standard treatment. If the tumour cannot be completely resected, radiation or chemotherapy may be given. Chemotherapy may be given to very young children instead of radiation therapy to avoid damage to the developing brain. Some of these tumours can progress to a higher grade, so it is important to be diligent about following up with the medical team after treatment.
Grade II – Low-grade Astrocytoma
An astrocytoma is a type of glioma that develops from star-shaped cells (astrocytes) that support nerve cells. The WHO classifies a low-grade astrocytoma as a grade II tumour. Grade 2 astrocytomas are defined as being invasive gliomas, meaning that the tumour cells penetrate into the surrounding normal brain, making a surgical cure more difficult. Other factors which influence survival include age and performance status (ability to perform tasks of daily living).
It is the second most common glioma, after glioblastoma, accounting for about 2-5% of all primary brain tumours in adults.
Symptoms- headache, seizures and weakness
- Consist of relatively slow-growing astrocytomas.
- Considered benign that sometimes evolve into more malignant or as higher grade tumors.
- They are prevalent in younger people who often present with seizures.
- Due to the infiltrative nature of these tumors, recurrences are relatively common.
Treatment depends on the size and location of the tumour. The doctor will most likely perform a biopsy or surgery to remove the tumour. Depending on the patient, radiation or chemotherapy after surgery is an option. Individuals with grade 2 astrocytoma have a 5-year survival rate of about 34% without treatment and about 70% with radiation therapy.
Grade III – Anaplastic Astrocytoma
An astrocytoma is a glioma that develops from star-shaped glial cells (astrocytes) that support nerve cells. An anaplastic astrocytoma is classified as a grade III tumour.
It is relatively rare, accounting for about 1-2% of all primary brain tumours
Symptoms- headache, nausea, vomiting, seizures, neurologic deficits, headaches, or changes in mental status.
- Grows faster and more aggressively than grade II astrocytomas.
- Tumor cells are not uniform in appearance.
- Invades neighboring tissue.
- Common among men and women in their 30s-50s.
- More common in men than women and accounts for two percent of all brain tumors.
The standard initial treatment is to remove as much of the tumour as possible without worsening neurologic deficits. Radiation therapy has been shown to prolong survival and is a standard component of treatment. Individuals with grade 3 astrocytoma have a median survival time of 18 months without treatment. Although temozolomide is effective for treating recurrent anaplastic astrocytoma, its role as an adjuvant to radiation therapy has not been fully tested.
Grade IV – Glioblastoma (GBM)
Glioblastoma multiforme (GBM) is the most common and deadliest of malignant primary brain tumours in adults and is one of a group of tumours referred to as gliomas. GBM develops from the lineage of star-shaped glial cells, called astrocytes, that support nerve cells. Primary GBM grows and spread to other parts of the brain quickly; they can become very large before producing symptoms, which often begin abruptly with seizures. Because of its lethalness, GBM was selected as the first brain tumour to be sequenced as part of The Cancer Genome Atlas, a national effort to map the genomes of the many types of cancer.
The incidence or the number of new diagnoses made annually is 2 to 3 per 100,000 people in the United States and Europe. GBM accounts for 12% to 15% of all intracranial tumours and 50% to 60% of astrocytic tumours.
Symptoms- headaches, nausea, vomiting, double vision and confusion or change in mental status.
- Can be composed of several different cell types.
- Can develop directly or evolve from lower grade astrocytoma or oligodendroglioma.
- Most common in older individuals and more common in men than women and less common in children.
- The cause is unknown, but increasingly research is pointing toward genetic mutations
Glioblastoma is a serious condition that will be treated by a multidisciplinary team consisting of neurosurgeons, oncologists and radiation oncologists. Surgical removal remains the mainstay of treatment, provided that unacceptable neurologic injury can be avoided. Although radiotherapy rarely cures glioblastoma, studies show that it doubles the median survival of patients, compared to supportive care alone.