Glioma Survival Rates and Life Expectancy

Glioma prognosis varies widely and depends on tumor grade, size, location, patient age, and the extent of tumor removal during surgery. Prognosis estimates life expectancy after diagnosis using population-level data, meaning that individual outcomes can differ. Here, we will discuss many of the factors involved in determining the prognosis, or recovery outlook, for patients diagnosed with glioma.

The World Health Organization (WHO) classifies glioma in 4 grades: Grade I through Grade IV. The higher the grade, the more invasive and malignant a particular glioma is. In general, a slow-growing and less invasive tumor usually carries a better prognosis than a fast-growing and invasive tumor.

It may be helpful to think of gliomas on a spectrum with low-grade gliomas being at one end of the spectrum with the best survival rates. Low-grade gliomas consist of WHO Grades I and II.  The prognosis is often excellent and thus tends to have a longer survival rate.

Several types of low-grade glioma carry survival rates that can surpass 15 years. For example, a pilocytic astrocytoma often has survival rates greater than 15 years (assuming the patient undergoes treatment).

In fact, an overwhelming majority (just under 95%) of patients with pilocytic astrocytoma are living 5 years after diagnosis.

On the other end of the brain tumor spectrum are those that are very invasive and malignant. High-grade glioma prognosis carries a poor survival time, and while treatment can help to prolong survival, this is usually and unfortunately measured in months rather than years.

Glioblastoma is the most aggressive and common malignant brain tumor; it makes up about 14% of all primary malignant brain cancers.

Growth Pattern: Characterized by rapid expansion. Unlike slow-growing tumors, glioblastoma grows too quickly for healthy brain tissue to accommodate.

Glioblastoma Life Expectancy

• 1-Year Survival: Many patients do not survive beyond the first year.
• 5-Year Survival: Estimated at less than 7% of patients.

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Age is an important factor to consider when trying to predict a patient’s prognosis and long-term glioma survival. However, it is important to remember that these trends do not guarantee specific outcomes. Many factors should be considered when predicting outcomes. Every patient’s case is unique.

• Children (Under 15): Pediatric patients with low-grade gliomas see survival rates above 90% for a 5-year period. However, high-grade gliomas carry a 20-30% 5-year survival rate.
• Young Adults (Ages 15–39): Statistically, this group has the most favorable prognosis. Low-grade gliomas generally have a favorable prognosis; approximately 26% of adolescents and young adults aged 15 to 29 survive for over five years. Higher-grade gliomas have poorer outcomes, with median survival rates around 1 to 2 years.
• Older Adults (Over 40): Prognosis generally declines with age due to decreased tolerance for aggressive treatments and the higher frequency of Grade IV glioblastomas. In patients over 65, the median survival for GBM is often 9 to 12 months. Lower-grade gliomas in older adults also tend to progress more rapidly than in younger patients.

Aggressive tumors often require aggressive treatments to slow their progression and maximize survival time. While these treatments aim to maximize survival time, they also involve significant side effects that impact quality of life. Many patients elect to undergo treatment so they can have more time with their loved ones.

Radiation is used after tumor resection to eliminate remaining cancerous cells, but it can also affect healthy brain tissue.

• Cognitive Impact: Potential for difficulty thinking, memory issues, and reduced processing speed.
• Inflammatory Response: Can trigger edema (brain swelling) and fluid shifts.
• Symptom Aggravation: Edema may worsen existing symptoms or cause new neurological issues to arise.

Chemotherapy involves systemic medication that is distributed throughout the entire body.

• Cognitive Risk: Like radiation, it carries a risk of "chemo-brain" or cognitive impairment.
• Variable Side Effects: Physical and mental impacts vary significantly depending on the specific drug protocol used.

People with gliomas with a genetic marker called MGMT methylation generally experience a better glioma tumor survival rate. MGMT (O6-methylguanine-DNA methyltransferase) methylation makes the tumor cells more responsive to certain chemotherapies, enhancing the effectiveness of the treatment and potentially improving glioma survival rate. 

MGMT is a gene responsible for repairing damaged cells, including fixing glioblastoma cells destroyed by chemotherapy. The methylation of MGMT hinders this repair mechanism, resulting in a higher mortality of tumor cells.

It’s normal to feel anxious and distressed after receiving a diagnosis. Finding the right support can significantly enrich emotional well-being and quality of life. 

Support groups provide a space to share experiences, exchange practical tips, and build a community with others in similar situations. Organizations like the National Brain Tumor Society and the American Brain Tumor Association offer various resources, including online and in-person support groups, educational materials, and caregiver resources. Engaging in these groups can help reduce feelings of isolation and give you the information you need to navigate the journey ahead.

• A recent diagnosis of glioma is very challenging for patients and family members alike.
• While it may be informative to understand which risk factors are associated with prolonged survival, it is more important to recognize that each patient is different.
• Health-related quality of life and maximizing quality time with loved ones are important when considering whether to initiate or remain under treatment. This is particularly critical with aggressive treatments which are more likely to come with side effects.
• In any case, a detailed and frank discussion with your care team is critical so that both the patient and physician have a clear understanding of the goals of care.

• National Brain Tumor Society
• American Brain Tumor Association
• Brain Tumor Foundation
• Children's Brain Tumor Foundation
• Pediatric Brain Tumor Foundation
• Glioblastoma Foundation