What Are the Side Effects of Radiation Therapy for Glioma?

Radiotherapy is a cornerstone of treatment for gliomas, particularly high-grade tumors such as glioblastoma. While it plays a critical role in controlling tumor growth and extending survival, the procedure often induces a range of side effects. These reactions are generally categorized into acute (occurring during or shortly after treatment) and late-term (emerging months to years later).

Acute Side Effects

The most common immediate reactions stem from inflammation and swelling in the brain tissue surrounding the tumor. Patients frequently experience increased intracranial pressure, which manifests as persistent headaches, nausea, and vomiting. Fatigue is another predominant symptom; many patients report profound tiredness that does not improve with rest, often requiring adjustments to their daily activities.

Skin changes at the radiation site are also typical. Similar to a severe sunburn, the scalp may become red, dry, itchy, or peel. In some cases, temporary hair loss (alopecia) occurs only in the area receiving direct radiation, while hair outside this field remains unaffected.

Cognitive and Neurological Changes

Gliomas often affect areas of the brain responsible for memory, attention, and executive function. Consequently, radiotherapy can exacerbate cognitive deficits. Patients may notice difficulties with concentration, short-term memory lapses, or slowed processing speed. These symptoms can be distressing but are often manageable with supportive care and cognitive rehabilitation strategies.

Late-Term Complications

Long-term risks include radiation necrosis, a condition where healthy brain tissue dies due to vascular damage caused by radiation. This can mimic tumor recurrence on imaging scans, necessitating advanced diagnostic techniques like perfusion MRI or PET scans for differentiation. Other potential late effects include seizures, hormonal imbalances if the pituitary gland was exposed, and, rarely, secondary malignancies.

Management and Support

Most acute side effects are temporary and resolve within weeks to months after treatment concludes. Corticosteroids, such as dexamethasone, are commonly prescribed to reduce cerebral edema and alleviate headache symptoms. Anti-nausea medications and skin care protocols can further mitigate discomfort. Close monitoring by a multidisciplinary team, including neuro-oncologists, radiation oncologists, and supportive care specialists, is essential to manage these reactions effectively and maintain quality of life throughout the treatment journey.