Brain Tumor

Brain tumors are classified based on their origin and molecular characteristics. If they arise from brain cells, they are referred to as primary brain tumors. If, on the other hand, they develop from tumor cells in other organs, they are secondary brain tumors, also known as brain metastases.

Brain tumors are classified based on their growth behavior:

Benign tumors usually grow slowly and are often clearly demarcated from the surrounding tissue.

Intermediate tumors exhibit behavior that falls between benign and malignant and may partially invade the surrounding tissue.

Malignant tumors often grow faster and infiltrate the brain tissue.

However, the classification is not always clear-cut. Some tumors grow slowly but still exhibit infiltrative behavior, and tumors that were initially less aggressive can change over time.

Depending on the part of the brain affected, a brain tumor can cause a wide variety of symptoms. Early detection is therefore often difficult. It may suddenly manifest itself through an epileptic seizure or initially cause only nonspecific symptoms that are common to many other conditions. The tumor’s location in the brain is key to determining the symptoms.

Possible symptoms include:

• Epileptic seizures
  Due to hyperexcitability of the healthy tissue at the edge of the tumor.
• Deficits or functional impairments
  Disturbances in speech, motor function, sensation, vision, thinking, memory, balance, orientation, mood, behavior, alertness, drive, or social behavior caused by pressure on or infiltration of the surrounding brain tissue.
• Headaches, nausea, vomiting
  In advanced tumors, increased intracranial pressure can cause these symptoms.
• Psychological and cognitive changes
  If the tumor is located in functionally less “critical” (non-eloquent) areas of the brain, it may go unnoticed for a long time. In such cases, nonspecific changes such as fatigue, forgetfulness, personality changes, disorientation, or confusion often occur. At the time of diagnosis, the symptoms have usually been present for weeks to a few months.

A brain tumor is usually diagnosed using magnetic resonance imaging (MRI). It provides detailed images of the brain tissue. Using different imaging sequences, various characteristics of a tumor can be visualized.

Depending on the findings, an MRI may already provide very clear evidence of a brain tumor, making surgery the next step. In other cases, the diagnosis remains unclear at first, so a tissue sample (biopsy) is necessary for a definitive diagnosis.

Early detection through blood tests or screening exams is currently not possible.

Surgery for a brain tumor has two goals: first, to remove the tumor as completely as possible; second, to preserve important brain functions.

A benign brain tumor can usually be cured after complete removal. For malignant tumors such as glioblastoma, removing as much of the tumor as possible improves the prognosis and survival rate, even though a cure is usually not possible.

At Inselspital, we use modern techniques such as neuronavigation, intraoperative ultrasound, intraoperative MRI, and fluorescence techniques to identify the tumor margins as precisely as possible.

However, preserving brain function always takes priority. For this reason, a small residual tumor is deliberately accepted if doing so can prevent neurological damage. In the case of benign tumors, this residual mass can be monitored over the years or, if necessary, treated with radiosurgery. For malignant, infiltrating tumors, radiation therapy and chemotherapy are added to the treatment.

To minimize the risk of permanent functional impairment, vital brain functions are continuously monitored during surgery.

Intraoperative neuromonitoring

Most patients can be discharged 5–7 days after surgery. This is usually followed by an appointment to discuss the histological examination of the removed tumor tissue.

If neurological impairments such as speech or movement disorders occur after surgery, inpatient neurological rehabilitation may be advisable. For milder symptoms, outpatient therapies such as physical therapy, occupational therapy, or speech therapy support the return to daily life.

For benign and some intermediate-grade tumors, regular follow-up examinations with MRI scans are sufficient. The follow-up intervals depend on the tumor type and the recommendations of the interdisciplinary tumor board.

If additional radiation and/or chemotherapy is required, further follow-up examinations are conducted in collaboration with the treating physicians in Oncology and Radiation Oncology.

To prevent a tumor from recurring after surgery or to stop residual tumor tissue from growing, adjuvant chemotherapy may be appropriate, depending on the tumor’s molecular characteristics and grade. Chemotherapeutic agents are drugs that damage the genetic material (DNA) of tumor cells, thereby inhibiting their growth.

For high-grade brain tumors (gliomas), a combined treatment of radiation therapy and chemotherapy with temozolomide (Temodal®) is often administered. This medication is taken in capsule form and is generally well tolerated.

Radiation therapy (radiotherapy) is a key component in the treatment of brain tumors. It is often used as an adjunct to surgery, particularly for high-grade tumors such as high-grade gliomas. The goal of treatment is to disrupt the cell division process of tumor cells, destroy any remaining cancer cells, and prevent further tumor growth.

High-energy X-rays are generated by a linear accelerator and precisely targeted at the tumor region so that the surrounding healthy brain tissue is spared as much as possible. Treatment is typically administered as conventional fractionated radiotherapy over several weeks. A typical standard protocol consists of 30 sessions of 2 Gy each, corresponding to a total dose of 60 Gy.

Radiosurgery is a highly focused, high-dose, one- to five-times radiation treatment offered as a treatment alternative to open surgery for small, well-defined tumors. At Inselspital, a device of the latest generation, the so-called CyberKnife, is used for this purpose. With the help of a computer-controlled robotic arm, the high dose of radiation is administered with razor-sharp precision.