WHAT NEUROLOGIST CAN DO FOR NEURO-ONCOLOGY PATIENTS?

I was intrigued by the title of Fiona M. McKevitt's article that I read in the February 2023 issue of Practical Neurology, "What Neurologist Can Do for Neuro-Oncology Patients?" Neuro-oncology is a medical discipline that deals with the management of central nervous system tumors and neurological complications of systemic cancers. Neurologists can play a crucial role in the management of patients with brain tumors alongside various other medical specialties.

Photo: Dilek Necioğlu Örken

How is a Brain Tumor Diagnosed?

In patients diagnosed with gliomas, headaches are the most common initial symptom. It occurs in 23.5% of patients and increases to 46.5% in patients presenting to the hospital. In addition to headaches, most patients may experience focal or non-focal symptoms (e.g., confusion, cognitive changes, and personality changes). Only less than 2% may present with no other symptoms or signs. Depending on the tumor's location, speech disturbances, visual impairment, and paralysis may also be detected. Epileptic seizures are common in individuals with brain tumors. Between 20-40% of all patients with brain tumors may experience seizures before diagnosis, and 20-48% may experience seizures after diagnosis. After diagnosis, the coordination of the patient's care involves medical oncology and neurosurgery. Furthermore, a neurology specialist may be involved in decisions regarding corticosteroid therapy and the initiation of antiepileptic drugs.

Corticosteroid Therapy in Brain Tumors

Patients with brain tumors often receive corticosteroid therapy to reduce tumor-related edema. However, several questions need to be answered before initiating treatment. Does the patient require this treatment? Does corticosteroid therapy hinder diagnosis? What is the appropriate dosage? How long should treatment continue? For example, if the tumour is asymptomatic and without mass effect, then they may not need corticosteroids or if there is suspicion of central nervous system lymphoma, corticosteroid therapy may reduce the diagnostic yield obtained from biopsy.

Neurological Side Effects of Cancer Treatments

Treatments applied to both central nervous system and systemic cancers can lead to neurological complications.

• Neurological complications of radiotherapy: Radiotherapy to the brain region can have both early and late complications. Early side effects may include nausea, hair loss, and seizures. Late complications may begin 6-12 months after treatment but may not become apparent for many years. These include neurocognitive effects, radiation-induced vasculopathy, SMART syndrome (stroke-like migraine attacks after radiation therapy), and radiation necrosis.
• Neurological complications of chemotherapy:
  1. Peripheral neuropathies
  2. Posterior reversible encephalopathy syndrome (PRES), characterized by headache, seizures, encephalopathy, visual disturbances, and focal neurological deficits. Vascular edema in the occipital and parietal white matter is typically seen on brain MRI. It is typically associated with hypertension but can also be related to chemotherapy agents (taxanes, vinca alkaloids, and platinum derivatives) and bevacizumab.
• Neurological complications of immunotherapies: The term immunotherapy encompasses a wide range of cancer treatments, including monoclonal antibodies (e.g., rituximab, cetuximab), immune checkpoint inhibitors (e.g., pembrolizumab, ipilimumab, nivolumab), cancer vaccines (e.g., talimogene laherparepvec), cytokines (e.g., interferon alpha, aldesleukin), and chimeric antigen receptor T-cell (CAR-T) therapy. As these drugs are used, their neurological side effects are becoming better understood.

In conclusion, patients with brain tumors require a multidisciplinary approach involving various specialists such as neurologists, neurosurgeons, neuroradiologists, neuropathologists, neuropsychologists, oncologists, neurorehabilitation specialists, clinical nurse specialists, and allied health professionals. Neurologists also assess patients receiving systemic cancer treatments who develop neurological side effects. Advances and intensified treatments have extended survival times, making neurological complications of brain tumors and systemic cancer treatments more common.

REFERENCE:
Fiona M McKevitt. What neurologists can do for neuro-oncology patients. Pract Neurol 2023;23:303–309. doi:10.1136/pn-2022-003665