Why Some Gliomas Return After Surgery or Radiation Therapy

When surgeons remove a glioma, they aim to take out as much of the tumor as possible while protecting critical areas of the brain. However, due to the infiltrative nature of gliomas, some cancer cells are likely to be left behind, no matter how carefully the surgery is performed.

“The goal is to remove as much of the tumor as we can while keeping the patient well neurologically,” Dr. Reid Thompson, Chair of Neurosurgery at Vanderbilt University Medical Center, tells SurvivorNet. In other words, to remove as much of the tumor as possible without causing harm to the patient.

Even though surgery can remove a large part of the tumor, any remaining cancer cells can continue to grow over time, leading to the tumor’s return. For this reason, surgery is often followed by other treatments, like radiation or chemotherapy, to try to eliminate any remaining cells.

The Role of ‘Cancer Stem Cells’ in Recurrence

One theory that researchers are studying involves something called cancer stem cells. These cells are thought to be especially resistant to treatments like surgery and radiation. Dr. Thompson explains that while most of the tumor cells may be destroyed by treatment, a small number of these cancer stem cells can survive and later “fuel” the tumor’s regrowth.

“These tumors don’t have a hard edge. They’re super toxic to the brain, gathering a blood supply and creating swelling and inflammation,” Dr. Thompson says. He adds that these cancer stem cells are tough to target because they often remain dormant during treatment, only to become active later.

Radiation & Chemotherapy Aren’t Always Enough

After surgery, many patients receive radiation therapy to target leftover tumor cells. Radiation works by using high-energy X-rays to damage the DNA of cancer cells, which can stop them from growing. Chemotherapy, which uses drugs to kill cancer cells, is another common treatment for gliomas.

While these treatments can help reduce the tumor’s size and slow its growth, they can’t always eliminate every cancer cell, as some cells may be resistant to radiation and/or chemotherapy.

This resistance is one of the reasons why gliomas are so challenging to treat. Standard treatments can shrink the tumor, but they may not completely get rid of the cancer.

Ongoing Research & Hope for the Future

Research is continuously evolving, and scientists are learning more about how to target these difficult cancer stem cells. Dr. Thompson mentions that one promising area of research involves understanding the unique “fingerprint” of each patient’s tumor at a molecular level. By studying these fingerprints, or molecular profiles, doctors hope to find new treatments that specifically target the cells most likely to cause recurrence.

In his interview with SurvivorNet, Dr. Thompson expressed optimism for the future: “There’s a lot of cool insight happening on the research front, and it gives those of us who take care of patients with gliomas and glioblastomas a lot of hope because it gives us hope for the future.”

In summary, gliomas are challenging to treat because they spread into nearby healthy brain tissue and often contain cancer stem cells. These characteristics make it difficult to completely resect them and resistant to standard treatments. Surgery, radiation, and chemotherapy each play a role in managing the tumor, but even with these approaches, gliomas can return. Researchers like Dr. Thompson are continually searching for better ways to target these stubborn cells and prevent recurrence, bringing hope for new, more effective treatments in the future.

Dr. Thompson emphasized to SurvivorNet that each glioma is unique, and understanding these differences is key to advancing treatment options. “No two gliomas are exactly the same,” he says, highlighting the importance of individually tailored treatment approaches.

With the right information, patients and families can feel more empowered and better prepared for the challenges that may lie ahead in the journey of glioma treatment.

Questions to Ask Your Doctor

If you or a loved one has been treated for a glioma, it’s important to understand the risk of recurrence and discuss ongoing care with your doctor. Here are some questions to ask:

• What are the chances that my glioma will return after treatment?
• Are there any specific cancer cells that might be resistant to treatment in my case?
• What follow-up treatments are available to help reduce the risk of recurrence?
• How often should I have check-ups or scans after my treatment?
• Are there any clinical trials or new therapies that might be effective if my glioma returns?

Patients should stay informed and discuss any concerns with their care team, emphasizing that understanding the nature of gliomas can help patients and families make well-informed decisions.

Learn more about SurvivorNet's rigorous medical review process.

---