Understanding Glioma: Challenges of Radiation Therapy vs. Surgery

“Gliomas don’t stay contained; they weave into the normal brain, which makes achieving a clean removal nearly impossible without affecting brain function,” Dr. Ganesh Shankar, a neurosurgeon at Massachusetts General Hospital, tells SurvivorNet.

This infiltrative nature of gliomas means that both surgery and radiation therapy play critical roles. However, each treatment comes with unique advantages and limitations. Understanding these can help patients make more informed decisions.

The Role of Surgery in Treating Gliomas

Surgery is often the first step in glioma treatment. The goal is to remove as much of the tumor as possible while preserving the normal brain function of the patient. The goal of surgery is to achieve a gross total resection, which means the surgeon tries to remove all visible tumor tissue. However, gliomas are usually spread out within the brain, meaning that even with a successful surgery, some cancer cells may remain behind.

“Even after a gross total resection, where we take out everything visible on the MRI, there are often microscopic cancer cells left behind,” Dr. Shankar explains. These remaining cells can cause the tumor to regrow, which is why surgery alone is rarely a complete solution for gliomas.

Also, surgery is particularly challenging when the tumor is located near essential parts of the brain, such as areas responsible for movement or speech. In these cases, surgeons must balance removing the tumor with preserving critical brain functions. When in these locations, surgeons may be less aggressive with the tumor resection to avoid causing neurologic deficits to the patient. This is one of the reasons why additional treatments, like radiation, are often used to address any remaining cancer cells.

When Radiation Therapy is Needed

Radiation therapy uses high-energy X-rays to target and destroy cancer cells’ DNA. For gliomas, radiation is often recommended after surgery to kill any remaining cells that could not be safely removed. Dr. Shankar emphasizes that radiation is part of the standard care following surgery for certain glioma types. “For glioblastomas, it’s standard to follow surgery with a combination of chemotherapy and radiation,” he says.

Radiation is especially helpful in cases where the tumor has infiltrated areas that are too risky to operate on. By focusing on the tumor site, radiation can shrink the tumor and slow its growth. However, patients must be aware that radiation therapy can come with side effects, as it may impact surrounding healthy brain tissue.

Balancing Surgery & Radiation

Choosing between surgery and radiation or using both depends on several factors. Low-grade gliomas, which are slower growing, may not require immediate radiation if surgery successfully removes most of the tumor. This is in contrast to high-grade gliomas, where radiation therapy may be more urgently recommended following surgery.

“For low-grade gliomas, sometimes we observe after surgery, and other times, based on the tumor’s behavior and location, we may recommend radiation or chemotherapy,” Dr. Shankar explains.

This individualized approach is essential in glioma treatment. A team of specialists, including neurosurgeons, radiation oncologists, and neuro-oncologists, work together to determine the best treatment plan for each patient.

Surgery vs. Biopsy

In some cases, a biopsy, a procedure that removes a small tissue sample for testing, may be recommended instead of surgery. A biopsy is less invasive and may be chosen if the tumor is in a high-risk area where surgery could lead to significant complications.

“A biopsy can reveal specific mutations that help us predict how the tumor will respond to treatments like radiation or chemotherapy,” Dr. Shankar explains. This understanding of the tumor’s molecular profile from a biopsy can provide crucial information for guiding treatment.

Potential Side Effects and Considerations

Both surgery and radiation therapy come with potential side effects, and it’s important for patients to be aware of them.

Brain Surgery risks include but are not limited to:

• Infection
• Bleeding
• Seizure
• Swelling in the brain
• Headache
• Blood clots
• Possible damage to nearby brain tissue (which can lead to neurological deficits)

Radiation Therapy side effects include but are not limited to:

• Fatigue
• Headaches
• Temporary or permanent memory and cognitive issues
• Patchy hair loss (that will re-grow)
• Radiation necrosis (when normal brain tissue reacts with the radiation therapy, which potentially leads to nausea, vomiting, and bad headaches)

Dr. Shankar says that he advises patients to discuss these risks openly with their care team to understand the potential impact on their lives. “Each patient’s treatment is unique, and it’s essential to balance the potential benefits of treatment with the risks.”

Questions to Ask Your Doctor

When facing a glioma diagnosis, it’s important to ask questions and understand your treatment options. Here are some questions to consider:

• What is the goal of surgery or radiation in my case?
• How will each treatment affect my quality of life?
• Are there specific risks or side effects I should be aware of?
• What are the chances of the tumor returning after treatment?
• Is my tumor type more likely to respond to one treatment over the other?

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