Low-Grade Astrocytoma Follow-up

• Most experts agree that pilocytic astrocytomas are curable with gross total resection and no further therapy. Gross total resection is also a cure for patients with subependymal giant-cell astrocytoma or pleomorphic xanthoastrocytoma. If a subtotal resection is obtained and tumor regrowth occurs, radiation therapy can be considered.
• The treatment of most low-grade astrocytomas is far less straightforward. Every possible combination of treatments has its proponents. Some clinicians favor a "wait and see" approach with presumptive low-grade astrocytomas that show little or no mass effect and in patients whose seizures are well controlled on medications. Others have suggested that all patients should have a biopsy to confirm the diagnosis and then early local-field radiation. Finally, others maintain that the best treatment begins with the maximum possible resection followed by radiation. While some have suggested that biopsy and radiation is as effective as gross total resection and radiation, oncologic principles suggest that removing as much tumor as possible is beneficial even if all neoplastic cells cannot be removed owing to the infiltrating nature of gliomas. The role of adjuvant chemotherapy is also controversial.
• Radiation has been shown in a number of series to be of benefit in patients who previously underwent intracranial surgery for low-grade astrocytoma. Early radiation may be more appropriate for patients who have undergone subtotal resection, while watchful waiting may be more appropriate for patients who have undergone gross total resection. If the tumor recurs after gross total resection, further surgery and radiation should be considered. The role of chemotherapy in low-grade gliomas is less well understood. It may be an option for those patients who have regrowth of tumor after surgery and/or radiation. Standardized clinical trials in patients with low-grade glioma are lacking.
• The possible roles of radiation and chemotherapy in low-grade astrocytoma of the spinal cord are unknown since long-term remission is common following surgery alone.

• Upon discharge, these patients need to have regular follow-up with a qualified neurologist/neuro-oncologist and/or neurosurgeon to address the complex issues that arise in patients with low-grade gliomas. If the patient also has epilepsy, consultation with an epileptologist may be useful.
• Patients with low-grade lesions who present with symptomatic hydrocephalus, seizures, and/or mass effect need to be admitted. Patients with seizures need to be started on an anticonvulsant regimen, and an inpatient workup may include further imaging studies and EEG.
• Patients with hydrocephalus from obstruction of CSF pathways by tumor require admission and possibly surgery for placement of a shunt and/or tumor resection.
• Patients with symptoms and/or signs of elevated intracranial pressure due to mass effect from tumor and edema should be admitted and started on a regimen of dexamethasone while surgery is considered.
• Determination of the exact timing of surgery and the type of surgery requires consultation with a qualified neurosurgeon.

As described above, an anticonvulsant (if seizures are present) and dexamethasone (if edema is significant) are continued on an inpatient or outpatient basis. In addition, antiulcer medication is given with the corticosteroid for GI prophylaxis.

At some institutions, transferring the patient to another facility may be necessary if the proper consultations cannot be obtained. Particularly in patients with significant hydrocephalus, transfer to a facility with neurosurgical coverage is indicated. However, in patients with no hydrocephalus, surgery can be scheduled on an elective, but preferably urgent, basis.

As already discussed, prognosis greatly depends on the pathology of the tumor. Taking many published series together, median survival duration is approximately 7.5 years. However, patients with pilocytic astrocytomas who undergo gross total resection can expect a cure. For low-grade astrocytomas that continue their relentless slow growth, progressive neurologic deficit may occur over a period of years.

In a large, multi-institutional study of patients with low-grade gliomas, Chang et al found that the University of California, San Francisco (UCSF) preoperative scoring system accurately predicted overall survival (OS) and progression-free survival (PFS). The 537 patients in the study were assigned a prognostic score based upon the sum of points assigned to the presence of each of the 4 following factors: (1) location of tumor in presumed eloquent cortex, (2) Karnofsky Performance Scale (KPS) Score ≤80, (3) age >50 years, and (4) maximum diameter >4 cm. Stratification of patients based on scores generated groups (0-4) with statistically different OS and PFS estimates (p < 0.0001). The 5-year cumulative OS probabilities stratified by score group were as follows: score of 0, 0.98; score of 1, 0.90; score of 2, 0.81; score of 3, 0.53; and score of 4, 0.46.^[4]