Dangerous brain tumor - How much do you know about glioma?

Author: Zhao Zheng, Associate Professor, Beijing Institute of Neurosurgery

Yang Changlin Beijing Neurosurgery Institute

Zou Lijuan, Associate Researcher, Beijing Neurosurgery Institute

Reviewer: Jiang Tao, Chief Physician, Beijing Neurosurgery Institute

Glioblastoma originates from glial cells and is the most common primary intracranial malignant tumor in adults. It has the characteristics of rapid growth, high recurrence rate, high disability rate and high mortality rate. The annual incidence of glioma is about 5 to 8 cases per 100,000 people, and it is the type of tumor with the highest mortality rate in young and middle-aged men[1-2]. The 5-year survival rate of highly malignant glioblastoma is less than 10%[3]. It imposes a heavy burden on patients, their families and society, and is one of the tumors that my country focuses on preventing and treating.

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1. What are the types of brain gliomas? What is the prognosis?

According to the 2021 fifth edition of the World Health Organization (WHO) classification of central nervous system tumors, adult diffuse gliomas are divided into three categories: oligodendrogliomas with isocitrate dehydrogenase (IDH) mutation and 1p/19q co-deletion, IDH mutant astrocytomas, and IDH wild-type glioblastomas [4].

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According to the degree of malignancy, brain gliomas are divided into low-grade gliomas and high-grade gliomas. Among them, low-grade gliomas can be further divided into grade 1 gliomas and grade 2 gliomas, and high-grade gliomas can be further divided into grade 3 gliomas and grade 4 gliomas. Among them, grade 4 brain gliomas with the highest malignancy account for more than half of all brain glioma cases, and the median survival time of patients is 14 to 18 months [3]. The following is a brief introduction to brain gliomas of different grades:

Low-grade glioma:

Grade 1 glioma: Common in children and young people, mainly including pilocytic astrocytoma, subependymal giant cell astrocytoma and other limited-growth gliomas. Most grade 1 gliomas can be cured by complete surgical resection and are the type of glioma with the best prognosis.

Grade 2 glioma: Common in adults, although the prognosis is relatively good, there is a risk of progression to a higher grade. Grade 2 glioma can be divided into two subtypes: oligodendroglioma and astrocytoma. Among them, the prognosis of grade 2 oligodendroglioma is better, with a median survival of up to 17 years; while the prognosis of grade 2 astrocytoma is poor, with a median survival of about 5 years [3].

High-grade glioma:

Grade 3 glioma: refers to anaplastic glioma, which is a high-grade glioma with strong heterogeneity and rapid progression. Grade 3 glioma is divided into two subtypes: anaplastic oligodendroglioma and anaplastic astrocytoma. Among them, the prognosis of grade 3 anaplastic oligodendroglioma is better, with a median survival of about 9 years; while the prognosis of grade 3 anaplastic astrocytoma is poor, with a median survival of less than 2 years [3].

Grade 4 glioma: Most are glioblastomas, and some are grade 4 astrocytomas. Glioblastoma is the most aggressive type of glioma, and is more common in middle-aged and elderly men. It progresses rapidly, causing high rates of disability and mortality, and the median survival of patients is only 14 to 18 months[3].

2. What are the common symptoms of brain glioma?

The symptoms of brain glioma vary depending on the size, location and growth rate of the tumor. Common symptoms include: headache, epileptic seizures, cognitive and personality changes, nausea and vomiting, vision, hearing or language problems, motor dysfunction, paresthesia, other neurological symptoms, etc. Some of these symptoms may be mild or develop gradually, while others may appear suddenly. If the above symptoms occur, it is recommended to seek medical attention in time and undergo relevant examinations to rule out or confirm brain glioma.

3. What examinations are needed for brain glioma?

The main examination methods for brain glioma are brain MRI and CT.

MRI: This is the preferred method for diagnosing brain gliomas. MRI can provide detailed brain structures and clearly show the tumor. It is particularly effective in showing the tumor boundaries and evaluating the impact of the tumor on surrounding tissues.

CT: CT scans provide cross-sectional images of the brain and help detect the location and size of brain gliomas. Although CT does not have the same spatial resolution as MRI, it is still useful in some acute situations (such as suspected bleeding or rapid assessment of intracranial pressure).

4. What are the treatments for brain glioma?

Surgical treatment: Surgery is the main method for treating brain gliomas. For low-grade brain gliomas, total tumor resection is the first choice, especially when the tumor is located in a non-functional area, and even super-total resection can be selected. When the tumor is located in a functional area, the maximum range of resection is selected. For high-grade glioblastomas, the surgical strategy is to safely resect as much as possible to the maximum extent. Research results show that compared with partial resection, total or subtotal resection can significantly prolong patient survival and provide better conditions for subsequent adjuvant chemoradiotherapy [5].

Adjuvant chemoradiotherapy: Since surgery cannot completely remove diffusely growing brain gliomas, almost all patients require adjuvant chemoradiotherapy. For patients with high-grade brain gliomas, it is recommended to start chemoradiotherapy as soon as possible after surgery. For patients with low-grade brain gliomas, there is no clear conclusion on when to start adjuvant treatment, and individualized treatment is required based on the patient's specific situation.

Emerging therapies: In recent years, significant progress has been made in the treatment of brain gliomas, including a variety of emerging therapies such as targeted therapy, electric field therapy, and immunotherapy. These treatments have shown great potential in brain gliomas. Eligible patients should consider participating in corresponding clinical trials at different stages of treatment to obtain the latest treatment opportunities.

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5. How to prevent brain glioma?

While the exact cause of brain gliomas is unknown, there are some risk factors and preventive measures, including:

Avoid high-dose ionizing radiation: Avoid contact with radioactive materials, and avoid unnecessary CT scans, positron emission tomography and other radiological examinations and treatments. Although there is currently no evidence that long-term exposure and use of non-ionizing radiation sources in daily life, such as electronic devices, will increase the risk of brain glioma, it is still recommended to use electronic devices rationally.

Genetic susceptibility and family history: Patients with rare genetic syndromes such as neurofibromatosis, tuberous sclerosis, Ley-Fraumeni syndrome, Turcot syndrome, or people with a family history of brain glioma should seek medical attention and undergo relevant examinations in a timely manner if they develop symptoms of early brain glioma.

Healthy diet and lifestyle: Maintaining a healthy lifestyle, including a balanced diet, moderate exercise and a positive attitude, is also an important measure to prevent cancer.

6. Precautions for brain glioma

In the face of the dangerous disease of brain glioma, patients and their families should maintain an optimistic and positive attitude and a good lifestyle, actively seek treatment, cooperate with the doctor's treatment plan and have regular check-ups, work closely with the medical team, work together to meet challenges, strive to obtain the best treatment results and improve the quality of life.

References

[1] National Health Commission Medical Administration Bureau, Chinese Anti-Cancer Association Brain Glioma Professional Committee, Chinese Medical Doctor Association Brain Glioma Professional Committee. Guidelines for the diagnosis and treatment of brain glioma (2022 edition) [J]. Chinese Journal of Neurosurgery, 2022, 38(8): 757-777.

[2]GBD 2019 Adolescent Young Adult Cancer Collaborators. The global burden of adolescent and young adult cancer in 2019: A systematic analysis for the Global Burden of Disease Study 2019［J］. Lancet Oncol, 2022,23(1):27-52.

[3]OSTROM QT, PRICE M, NEFF C, et al. CBTRUS Statistical Report: Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2016-2020［J］. Neuro Oncol, 2023,25(12 Suppl 2):iv1-iv99.

[4]LOUIS DN, PERRY A, WESSELING P, et al. The 2021 WHO Classification of Tumors of the Central Nervous System: A summary［J］. Neuro Oncol, 2021, 23(8):1231-1251.

[5] ROSSI M, GAY L, AMBROGI F, et al. Association of supratotal resection with progression-free survival, malignant transformation, and overall survival in lower-grade gliomas［J］. Neuro Oncol, 2021, 23(5):812-826.