How Gamma Knife Surgery Treats Brain Tumors?

Gamma Knife surgery is a non-invasive stereotactic radiosurgery instrument involving no scalpel or incision designed for treating brain tumors and other brain diseases. It delivers highly focused radiations directed to the tumor with precise. Gamma Knife offers a non-surgical alternative treatment for some brain tumors. It also enables us to deal with some risky and inoperable brain tumors. Today, it is commonly used for specific benign brain tumors, such as vestibular schwannomas and meningiomas, as well as brain metastases, which refer to a tumor spreading from another part of the body to the brain.

What is Gamma Knife Surgery?

Many patients around the world seek to understand what Gamma Knife surgery is and explore which is the best hospital for Gamma Knife surgery. Briefly, Gamma Knife is a radiosurgery device developed for the treatment of neurological diseases. It is primarily used to treat brain tumors and vascular conditions such as arteriovenous malformations (AVM) and cavernomas. Gamma Knife designed in Sweden and first used for treatment in 1968. It began being used in England in 1984 and in the USA in 1987. Over time, as its benefits became more recognized, it gained acceptance worldwide. In Türkiye, the first Gamma Knife unit was established in 1997 by Professor Necmettin Pamir, the founding rector of Acıbadem University and a neurosurgery specialist.

What does Gamma Knife Surgery Treat?

• The majority of Gamma Knife applications target brain tumors. Gamma Knife therapy stands out as an effective, permanent, and safe treatment option for certain types of tumors. It is most commonly used to treat benign brain tumors, such as meningiomas and vestibular schwannomas. Other benign tumors that can be treated with Gamma Knife include pituitary tumors, trigeminal schwannomas, hemangioblastomas, pineal region tumors, chordomas, craniopharyngiomas, and glomus tumors.
• Gamma Knife surgery is frequently used to treat brain metastases and is effective in cases of both single and multiple metastases.
• Gamma Knife radiosurgery is considered a valuable treatment for recurrent tumors. If a tumor has been surgically removed but has returned, Gamma Knife can help control its size, preventing further growth without requiring additional surgery.
• In some types of tumors, total resection is not feasible due to high morbidity rates. In such cases, a subtotal resection followed by Gamma Knife application is considered as a most effective treatment option.
• Outside of brain tumors, Gamma Knife can also be used to treat AVMs and cavernomas, which are vascular conditions of the brain. Additionally, this technology has been applied in the treatment of functional brain diseases, such as Parkinson’s disease and trigeminal neuralgia.

How Gamma Knife surgery Treats Brain Tumors?

All operations performed in brain surgery require an incision, even if small, in the skull. However, Gamma Knife surgery offers the ability to treat patients without making any incision. The treatment works by precisely directing gamma rays to the tumor, preventing its growth and, in some cases, reducing its size. Treatment can be completed in a single session or, depending on the case, extended up to five sessions.

How Does Radiosurgery Work for Brain Tumors?

Gamma Knife treatment yields gradual outcomes. In other words, the results are not immediate. Radiosurgery damages the genetic (DNA) in the tumor cells over time, causing them to lose their ability to reproduce and leading to gradual shrinkage of the tumor. This process typically takes 12 to 18 months. The main goals of Gamma Knife treatment are to prevent further tumor growth, alleviate symptoms, and reduce the tumor size.

What are Procedure Details?

First, the patient’s MRI is taken, and then they are brought to the Gamma Knife machine. A stereotactic frame is attached to the patient’s head to ensure precision. A neurosurgeon targets the tumor precisely by directing rays directly to it with high accuracy, ensuring minimal radiation exposure to surrounding tissues. Afterward, the patient is observed briefly before being discharged. The entire process takes half a day, and no additional medication is needed post-procedure.

Who is not a Candidate for Gamma Knife Surgery?

Not all brain tumors are suitable for Gamma Knife treatment. Who is not a candidate for gamma knife surgery? These include:

• Tumors larger than 4 cm in size.
• Cases with more than 8-10 metastases in the brain (in such situations, whole-brain radiotherapy is often considered).
• Tumors located near sensitive areas, such as the optic nerve or brainstem, where intense radiation could cause harm.
• If a tumor can be safely and completely removed without damaging the patient’s functional abilities, surgery is typically the best option for a cure.

Additionally, in cases of emergencies like tumor-related bleeding, functional impairments, or hydrocephalus, immediate surgical intervention may be required.

What age is Gamma Knife Surgery for?

Gamma Knife Surgery is most commonly performed on adult patients, with virtually no upper age limit. When necessary, Gamma Knife can also be applied to children. While there is no strict lower age limit, patients as young as 3 to 4 years old may be suitable candidates for Gamma Knife Radiosurgery.

Gamma Knife Surgery Success Rate

When we focus on brain tumor types suitable for Gamma Knife, one study shows the percentage of these tumors treatable with this technology. The findings are as follows:

Studies conducted over the years have proven that the Gamma Knife surgery success rate is high. For illustration, vestibular schwannomas are rather specialized targets for radiosurgery. Many studies show that Gamma Knife controls the growth of this tumor in 97-98% of patients. Additionally, in most cases, the tumor size decreased during follow-up.

In brain tumor treatment, success is not only measured by the ability to treat tumors but also by the preservation of functional abilities such as walking, hearing, and speaking.  Vestibular schwannomas develop on the balance and auditory nerves, meaning these vital functions must be protected during treatment. One of the key advantages of Gamma Knife in treating vestibular schwannomas is its ability to preserve hearing. Hearing function is maintained in 50 to 75% of patients, making it a crucial aspect of the Gamma Knife surgery success rate.

When should I see a Healthcare Provider?

When patients are diagnosed with a brain tumor, AVM, or cavernoma, and surgical treatment is offered, it may be a good idea to visit a hospital that utilizes Gamma Knife and find out if is there a non-surgical treatment of the disease. When patients visit a neurosurgeon who can perform surgery and radiosurgery, they can find out in detail which procedure is better for him/her. At Acıbadem, we can offer both surgical treatment and Gamma Knife treatment to patients who apply to our clinic worldwide.

Life Expectancy after Gamma Knife Surgery

Life expectancy after Gamma Knife surgery varies depending on the type of tumor being treated. For benign tumors, the prognosis is often quite favorable. For example, a study involving 200 patients with grade 1 meningiomas reported progression-free survival rates of 98.5% at 5 years and 97.2% at 10 years following Gamma Knife treatment.

Gamma Knife surgery also enhances the survival rate of patients with brain metastasis. Its tumor control rate is very high for almost all types of cerebral metastatic cancers. When brain metastases are irradiated with whole brain radiotherapy, the treatment response is poor in some cancers such as melanoma, renal cell carcinoma and sarcoma. However, when the cancer is irradiated with Gamma Knife, this resistance is significantly reduced because the metastatic focus is irradiated with very high doses. This effectively controls brain metastases and improves patient survival rates. However, in brain metastases, life expectancy after gamma knife surgery still largely depends on the ability to control the primary tumor.

Why Acıbadem for Treatment?

There is a limited number of centers worldwide that offer Gamma Knife treatment, leading many patients to seek this treatment abroad.  Acıbadem, a prestigious hospital group in Türkiye renowned for its neurosurgery expertise, is one of the few centers utilizing Gamma Knife for brain tumor treatment. Today, Acıbadem is considered one of the best hospitals for Gamma Knife surgery. For more than 30 years, many patients have chosen Acıbadem Neurosurgery Department to receive advanced treatment and care from all around the world. Acıbadem continues to meet the high demand for Gamma Knife therapy.