Glioma: The Treatment Path
- For low-grade gliomas, surgery is typically part of the initial treatment plan. The goal is to remove as much of the tumor as possible without causing significant neurological side effects, or maximal safe resection.
- When surgery is not possible or does not remove as much of the cancer as planned, other treatment options, like chemotherapy, radiation, or targeted therapy, may be used.
- Targeted therapies for gliomas with a marker known as an IDH mutation are a new and exciting option for patients
- When glioma is completely removed with surgery, observation may be an option. Observation is particularly appropriate for low-risk patients with favorable molecular profiles and no residual tumor visible after surgery.
The treatment approach for this type of glioma is multifaceted, with surgery as the cornerstone of initial management. The goal of surgery is to remove as much of the tumor as possible without causing significant neurological side effects, or maximal safe resection.
Read MoreSurgery: What to Expect
To achieve maximal safe resection with low-grade gliomas, surgeons will use advanced strategies, such as:- Intraoperative Functional Mapping: This technique identifies critical areas of the brain responsible for essential functions such as speech and motor skills, enabling the surgeon to avoid these regions and minimize the risk of neurological damage.
- Stereotactic Neuro-Navigation: This technology provides a three-dimensional reconstruction of the brain, helping surgeons plan the operation with precision and navigate complex tumor locations during the procedure.
These advanced tools and techniques ensure that surgery is as safe and effective as possible, setting the stage for further treatments if needed.
Ideally all of the above options are used, however some community and even larger hospitals do not have advanced functional mapping available. Not every center will be equipped with this technology but consider asking your doctor about them.
Treatment After Surgery
Despite successful surgery, low-grade gliomas can recur, sometimes years or even decades later. The likelihood of recurrence depends on various factors, including the extent of tumor resection, the patient’s age, and the molecular subtype of the glioma. Based on these risk factors and discussions with their medical team, patients may require additional treatments such as chemotherapy, targeted therapy, or radiation.
Chemotherapy
Systemic therapy (or therapy that treats the whole body) is often recommended for patients classified as high-risk or those with recurrent low-grade gliomas.
Two established chemotherapy options include:
- PCV Regimen: This is a combination of procarbazine, lomustine, and vincristine. PCV is typically administered after radiation therapy and has been shown to improve overall survival in certain high-risk patients.
- Temozolomide (TMZ): This oral chemotherapy drug is often used as an alternative to PCV, especially for patients who may not tolerate more aggressive regimens. TMZ is particularly effective for gliomas with specific molecular profiles, such as methylated MGMT promoter status.
Targeted Therapy
Targeted therapies represent an exciting frontier in glioma treatment. These therapies focus on specific genetic and molecular abnormalities driving tumor growth.
Examples include:
- BRAF/MEK Inhibitors: Drugs like dabrafenib and trametinib are effective in gliomas with BRAF mutations, offering a tailored treatment option for these specific cases.
- IDH Inhibitors: Many low-grade gliomas carry an IDH mutation, making patients eligible for drugs like Vorasidenib. This oral medication has shown impressive progression-free survival benefits in clinical trials, delaying the need for additional interventions such as chemotherapy, radiation, or further surgery.
“With the new indications for IDH inhibitors, we can offer this treatment option to patients prior to chemoradiation when there is residual tumor that’s not very large,” Dr. Ghiaseddin explains.
Radiation Therapy
Radiation therapy is another cornerstone of low-grade glioma treatment, often used in conjunction with chemotherapy.
High-energy X-rays are delivered to the tumor site using advanced techniques such as:
- Volumetric Modulated Arc Therapy (VMAT): This method delivers radiation in a precise, continuous arc, minimizing exposure to surrounding healthy tissue.
- Stereotactic Radiosurgery (SRS): A non-invasive option that delivers a high dose of radiation in a single session, targeting the tumor with exceptional precision. This is typically not recommended for low-grade glioma but it is worth asking about as an option in addition to proton therapy.
The duration and frequency of radiation treatments vary based on the tumor’s location and size. Dr. Ghiaseddin cautions about potential long-term effects of radiation, emphasizing the need to balance its benefits with potential risks, such as cognitive decline or secondary malignancies.
What if Surgery is Not an Option?
In cases where gliomas are too extensive or involve critical areas of the brain, such as the brainstem, surgery may not be feasible.
For these patients, alternative treatments like chemotherapy, targeted therapy, and radiation become the primary options. The choice of treatment depends on the tumor’s molecular characteristics, location, and the patient’s overall health.
When is Observation an Option?
For patients with completely resected low-grade gliomas, observation may be a viable strategy. This approach involves close monitoring with regular imaging studies, such as MRI or CT scans, to detect any signs of tumor recurrence.
Observation is particularly appropriate for low-risk patients with favorable molecular profiles and no residual tumor visible after surgery. However, it’s important to note that many low-grade gliomas can eventually transform into high-grade gliomas. If recurrence occurs, patients may still be candidates for additional surgery or other treatments.
The Role of Molecular Profiling in Treatment
One of the most significant recent advancements in glioma management is the integration of molecular profiling into treatment planning. Understanding the genetic and molecular characteristics of the tumor allows doctors to tailor therapies to each patient’s unique disease profile.
The following genetic characteristics are important for glioma:
- IDH Mutations: Patients with IDH-mutant gliomas may benefit from targeted therapies like Vorasidenib, which specifically inhibit the mutated enzymes driving tumor growth.
- 1p/19q Co-Deletion: This genetic alteration is associated with better responses to PCV chemotherapy and improved overall survival.
- MGMT Promoter Methylation: This biomarker predicts better outcomes with temozolomide chemotherapy, guiding treatment decisions for high-risk patients.
Multidisciplinary Care for Low-Grade Gliomas
Treating low-grade gliomas requires a collaborative approach involving multiple specialists, including neurosurgeons, neuro-oncologists, radiation oncologists, and pathologists. This multidisciplinary team works together to develop a personalized treatment plan that maximizes efficacy while minimizing side effects. Regular communication among team members ensures that patients receive the most up-to-date and effective care.
The management of low-grade gliomas has evolved significantly, with advancements in surgery, chemotherapy, radiation, and targeted therapies offering new hope for patients.
While surgery remains the cornerstone of treatment, additional therapies are often necessary to address recurrence and reduce the risk of progression. The integration of molecular profiling into treatment planning has ushered in an era of precision medicine, enabling tailored therapies that improve outcomes and quality of life. Patients and their families should engage in open discussions with their medical teams to fully understand their options and make informed decisions about their care.
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