Precision Without a Scalpel: The Future of Brain Tumor Treatment—An Expert Interview with Dr. Christoph Weber, M.D.

The fundamental goal of radiation therapy is to deliver a specific dose precisely to the tumor. In the past, the entire brain was irradiated for this purpose. Today, the clear objective is to spare the surrounding healthy tissue as much as possible. The brain, in particular, contains many sensitive structures that must be preserved at all costs. This is where the so-called dose gradient plays a crucial role: it describes how quickly the radiation intensity decreases outside the tumor. The steeper the dose gradient, the better healthy tissue is protected—and this is precisely where the unique strength of radiosurgery lies.

Another key difference concerns the duration of treatment: While conventional radiation therapy is typically administered over several weeks with daily sessions, stereotactic radiosurgery is usually performed in a single session lasting less than an hour. This is made possible by a different dosing principle: Instead of spreading the radiation dose over time (temporal fractionation), as in conventional radiation therapy, radiosurgery employs “geometric fractionation.” Put simply: In conventional radiation therapy, the dose must be spread over several sessions so that the healthy brain tissue can recover between individual treatments, since the rays always come from the same direction. In radiosurgery, on the other hand, many weak rays from different directions strike the tumor. Each individual beam carries too little energy to damage the surrounding tissue. However, where all the beams converge within the tumor, the energy adds up. This allows the tumor cells to be destroyed in a targeted manner while sparing healthy tissue as much as possible.

We work with the state-of-the-art ZAP-X system, which was developed specifically for the radiosurgical treatment of tumors in the head region. This first and only device of its kind in all of Switzerland represents one of the most innovative advancements in radiosurgery.

Each patient receives a personalized radiation treatment plan. Treatment planning is carried out by an interdisciplinary team consisting of neurosurgeons, radiation oncologists, and medical physicists. First, the tumor is precisely localized using high-resolution MRI imaging. The tumor is then precisely mapped on a computer. This is comparable to a topographic map, where the contour lines visualize the radiation dose. The goal is to plan the radiation treatment so that the radiation dose is maximized within the tumor and minimized in the surrounding healthy tissue. Using three-dimensional image data and planning software, we calculate the optimal radiation dose and the radiation angles. Precise targeting and careful planning are crucial to fully leveraging the benefits of stereotactic radiosurgery and offering patients a gentle yet highly effective treatment. The outpatient procedure is performed without anesthesia and usually in a single session. During treatment, the patient is gently secured with a custom-fitted face mask to prevent movement. The actual radiation treatment is completely painless and lasts approximately 45 to 60 minutes, depending on the tumor size. Afterward, the patient can leave the clinic and resume their daily routine as usual.

Stereotactic radiosurgery is particularly suitable for benign tumors such as schwannomas or neurinomas (including vestibular schwannomas, formerly known as acoustic neuromas), meningiomas, or pituitary adenomas. We also treat brain metastases from malignant diseases very successfully. In addition, we use this technique for vascular lesions, such as arteriovenous malformations (AVMs) and glomus tumors, as well as for functional disorders such as trigeminal neuralgia. Other applications for radiosurgery include treatment-resistant tremors and epilepsy, as well as tumors of the eye. For primary brain tumors such as glioblastoma, surgery is the primary treatment; however, in cases of recurrence, radiosurgery can be a valuable option.

Radiosurgery is a non-invasive treatment method. This eliminates surgery-related risks such as bleeding, infections, damage to nerve structures, or complications like cerebrospinal fluid fistulas. Patients benefit from a faster recovery and avoid long hospital stays. This is a major advantage, especially for older patients or those with pre-existing conditions. But radiosurgery also offers a treatment alternative for patients who are hesitant about brain surgery, whether due to fear or other reasons.

Serious complications such as radiation necrosis are very rare due to the high precision of the technique. Radiation necrosis occurs primarily when a high radiation dose is applied to a large volume of healthy brain tissue. This is precisely where the decisive advantage of radiosurgery lies: Thanks to the steep dose gradient and targeted irradiation from numerous different directions, the impact on the healthy tissue surrounding the tumor is minimized. Rare side effects, such as mild swelling or inflammatory reactions, can be effectively managed with corticosteroids.

For benign tumors such as vestibular schwannomas, meningiomas, or pituitary adenomas, tumor control rates of 95 to 98% are achieved. In most cases, tumor control means stopping tumor growth. Complete removal is not necessarily required for benign tumors. Reducing the tumor’s size or halting further growth is usually sufficient to alleviate existing symptoms and prevent the onset of new symptoms. If the tumor grows again, we can easily repeat the treatment.

The treatment costs are significantly lower than those of traditional surgery. It’s important to keep in mind that conventional surgery usually requires a hospital stay, intensive monitoring if necessary, and a longer postoperative recovery period. These factors not only lead to higher medical costs but also to longer periods of downtime for patients. With stereotactic radiosurgery, these expenses are eliminated. The treatment is performed on an outpatient basis; patients can return home the same day and quickly resume their daily routines. In Switzerland, the costs are fully covered by mandatory health insurance. In Germany, coverage is provided following a prior application for cost reimbursement, particularly when radiosurgery is considered an equivalent or superior alternative to surgery. Overall, radiosurgery offers a highly attractive solution—both medically and economically—for many patients.

Stereotactic radiosurgery marks a significant advance in medical development: It enables treatment outcomes that not only meet but often exceed the previous standard—while at the same time significantly reducing the burden on patients and minimizing side effects, all at a fraction of the usual cost.

Thank you very much, Dr. Weber, for this fascinating insight into modern radiosurgery!

Advantages of radiosurgery with ZAP-X at a glance:

• Precise treatment: Millimeter-precise focusing of radiation on the tumor.
• Preservation of healthy tissue: Minimal impact on surrounding structures due to a steep dose gradient.
• Outpatient & quick: Treatment usually completed in a single session, without hospitalization.
• No surgery required: No scalpel, no anesthesia, no surgical risks.
• High success rates: 95–98% for benign brain tumors such as meningiomas and acoustic neuromas.
• Repeatable therapy: Re-irradiation is possible if the tumor grows back.
• Also suitable in cases of recurrence or following prior surgery or radiation therapy.
• Also suitable for inoperable tumors or those located in highly sensitive and functionally critical, so-called “eloquent,” areas of the brain.
• Ideal for high-risk patients: Particularly suitable for patients at high surgical risk or of advanced age.
• High cost-effectiveness, as the treatment costs only a fraction of the cost of open surgery.