Glioblastoma is a highly aggressive and fast-growing type of brain tumor, categorized as a grade IV astrocytoma. It originates from astrocytes, which are star-shaped support cells in the brain. This tumor infiltrates brain tissue, making it particularly challenging to treat effectively.
Components of Standard Care
Surgical resection is the initial approach, aiming for maximum safe tumor removal. Surgeons remove as much visible tumor as possible while preserving healthy brain tissue to minimize neurological damage. This debulking reduces tumor volume, alleviates symptoms, and improves subsequent therapies.
Following surgery, radiation therapy targets remaining tumor cells. High-energy beams, such as X-rays or protons, are directed at the tumor site. Radiation damages cancer cell DNA, preventing growth and division. It is administered in daily fractions over several weeks to maximize effect while allowing normal brain tissue to recover.
Chemotherapy, often using temozolomide, is another component. Temozolomide is an oral alkylating agent that damages cancer cell DNA, leading to their death. This drug crosses the blood-brain barrier, a protective filter preventing many substances from entering the brain, making it effective against brain tumors. Administration is timed to work with other treatments.
The Standard Treatment Protocol
The standard approach for newly diagnosed glioblastoma follows the Stupp Protocol (2005). This protocol combines radiation therapy with temozolomide chemotherapy. The initial phase, concurrent chemoradiotherapy, involves daily radiation fractions and a daily oral dose of temozolomide.
During the concurrent phase, radiation therapy is administered at 2 Gray (Gy) per day, five days a week, for 60 Gy over six weeks. Temozolomide is given at 75 mg per square meter daily, seven days a week, throughout the radiation period. A four-week break follows this initial phase for recovery.
The second phase, adjuvant chemotherapy, involves additional cycles of temozolomide alone. Patients receive 150 to 200 mg per square meter for five days during each 28-day cycle. This adjuvant treatment continues for six cycles or until disease progression. This combined approach aims to maximize glioblastoma cell destruction while managing side effects.
Managing Treatment Effects
Glioblastoma treatment leads to various side effects, requiring careful management for patient comfort and quality of life. Fatigue is common, often stemming from the disease, surgery, radiation, and chemotherapy, and is managed through rest and energy conservation. Nausea and vomiting, frequently associated with chemotherapy, are controlled with anti-nausea medications.
Hair loss is another side effect of chemotherapy, though temporary. Neurological deficits, such as weakness, speech difficulties, or cognitive changes, may occur depending on tumor location and extent of surgery or radiation. These deficits are addressed through rehabilitation therapies, including physical, occupational, and speech therapy, to help patients regain function. Supportive care also addresses headaches, seizures, and mood changes with appropriate medications and psychological support, focusing on overall well-being.
Prognosis and Outlook
Despite aggressive treatment, glioblastoma carries a challenging prognosis. Median overall survival for patients receiving the Stupp protocol is approximately 14 to 16 months. Individual outcomes vary based on factors like age, overall health, and specific molecular characteristics of the tumor. For example, MGMT promoter gene methylation is associated with increased temozolomide sensitivity and may lead to improved survival.
Glioblastoma recurrence remains high, even after standard treatment. This is due to the tumor’s infiltrative nature, making it difficult to eradicate all cancer cells. Given these challenges, clinical trials explore new therapies beyond current standard of care. These trials investigate novel drugs, immunotherapy, and targeted therapies, offering hope for improved outcomes and extended survival.