In this article, we will discuss the:
- Types of brain tumours
- Symptoms of brain tumours
- Different ways to diagnose brain tumours
- Treatments available for brain tumours in Singapore
Often, individuals will receive lots of information, possibly from many people, about the various treatment options. This can be confusing and difficult to comprehend, and extremely distressing if a decision is to be made within a short space of time. All these make it even more important to consult a neurosurgeon who specialises in the treatment of brain tumours and who can provide tailored advice about treatments and their alternatives.
Figure showing MRI of common types of brain tumours and their diagnosis Types of brain tumours
There are more than 125 different types of the brain. A primary brain tumour begins somewhere in the brain while a secondary (or metastatic) brain tumour originates from other parts of your body and spreads to the brain.
Primary brain tumours are generally referred to by their grades:
- Low grade tumours are benign, slow growing and less likely to spread to other parts of the brain, and have a lesser chance of recurring with the appropriate treatment.
- High grade tumours are malignant, fast growing and more likely to spread to other parts of the brain, and more likely to recur even if treated intensively.
Primary brain tumours are also classified based on the cell origin. In Singapore, gliomas, which originate from glial cells, are the most common type of brain tumours in adults, accounting for 78% of malignant brain tumours (also known as glioblastoma).
Other common types of primary tumours include vestibular schwannoma (acoustic neuroma), meningioma, and pituitary adenoma.
Importantly, low grade tumours can progress to become high grade over time. A tumour of any grade can be serious if it expands into surrounding healthy brain tissues especially those that control motor, speech or visual functions, or if it disrupts the normal flow of the fluid in the brain.
Secondary brain tumours refer to those that have spread from another region in the body (“metastasis”). Any cancer can spread to the brain, with the common ones being lung, breast, colon, kidney and melanoma. Brain metastases can be multiple and have been found in 10 to 30% of adults with cancer.
Symptoms of brain tumours
Symptoms are related to location within the brain where the tumour developed. For instance, a tumour pressing on the speech pathway will cause speech impairment, while one that has invaded the tracts in the brain that controls movement will lead to weakness in the hand, leg or both.
Other possible neurological symptoms include headache, seizures, visual problems, imbalance or difficulty walking, confusion in everyday matters, or trouble with memory.
Do note that symptoms of a brain tumour often resemble those caused by other conditions. If you experience these symptoms and have concerns, consult a specialist to get it checked.
Diagnosis of brain tumours
Accurate diagnosis is critical to make an informed decision about the appropriate treatment plan.
- A comprehensive evaluation, inclusive of medical history and neurological examination, can provide clues to the parts of your brain that could be affected by the tumour. Examinations help determine the type of imaging required (such as MRI brain or spine).
- A magnetic resonance imaging (MRI) is commonly used to provide the neurosurgeon with valuable insights on the tumour characteristics such as size, location and possibly, grade. A contrast dye may be injected through a vein in your arm during your MRI study to better visualise blood vessels around and within the tumour. A number of specialized MRI scan components, including magnetic resonance spectroscopy and functional MRI, may help your neurosurgeon better evaluate the tumour and plan treatment.
- Diffusion tensor imaging (DTI) is a special technique that is used to visualise brain connections (“white matter tracts”). White matter tracts are like “information expressways” which connect part of the brain and pass information from one part of the brain to others. Research studies have shown a tendency for tumours to grow along the white matter tract direction, which is important for surgical planning and prediction of recurrence. Knowing where the brain tumour lies in relation to these connections can help neurosurgeons know where to avoid damaging the major tracts.
- Positron emission tomography (PET) scan is an alternative that has advantages over conventional MRI as it is able to better distinguish between benign and malignant brain tumours. New radiotracers are available in Singapore. They are considered to be safe, disappear from the body within a few hours after administration, and are highly specific. This special type of PET (with new tracers) can more accurately determine whether tumour cells are present.
Treatment for brain tumours
- The first-line treatment of brain tumour is often surgery. Surgery is the standard of care for high grade glioma tumours. The goal of neurosurgery is to remove as much tumour as possible with minimum damage to surrounding normal brain tissue. Surgery also provides the opportunity to take a sample of the brain tissue (“biopsy”) for further molecular and genetic tests. These tests will reveal valuable information for a more accurate diagnosis on the type of tumour and predict the patient’s response to certain treatments (such as chemotherapy and radiation). In some patients, a shunt may be necessary prior to surgery.
- Sometimes, surgery may not be possible (or required right away), biopsies can be obtained using a needle (stereotactic biopsy).
- Radiation and chemotherapy may be required, on their own or as additional therapies after surgery.
- Targeted therapy is a new type of personalised cancer treatment that has been increasing used as a standard of care in many top cancer centres worldwide, including ours. Targeted therapy drugs work by intefering with molecules that help cancer cells to grow and spread. These molecular targets are identified with next-generation sequencing. The difference compared to traditional chemotherapy drugs, is that targeted therapy drugs have a targeted effect on the cancer cells and generally leave normal, healthy cells alone. In contrast, chemotherapy drugs are cytotoxic to most cells, meaning they can damage and kill both normal, healthy cells as well as cancer cells. Targeted therapy stops cancer cells from dividing and making new cancer cells, while traditional chemotherapy works by killing the cancer cells that have already been made. Hence, targeted therapy drugs often have fewer side effects and, in some instances, are more effective.
- Tumour treating fields (TTF): A wearable, portable device (Novocure) that produces electric fields can be used in combination with chemotherapy. The low-intensity electrical fields disrupt the ability of the fast-growing cancer cells to divide and multiply but don't harm the slow-growing normal brain cells. TTF, when used with chemotherapy, has shown promising results for extending the life expectancy of patients with glioblastoma, the most common and aggressive type of adult brain cancer.
A new way of thinking about brain tumour patient care
- When one hears about advancements in brain surgery, it’s often a report of a new technology, surgical approach, or technique. But just as important are new ways of thinking that lead to shifts in how we care for patients.
- In the last 20 years, the success of brain tumour surgery has focused mostly on things like how much tumour we remove during the surgery and how long the patient lived after diagnosis. These are still important factors to take into account.
- But today, one of our most important goals in brain tumour surgery is to improve or maintain our patients’ quality of life. Extending life expectancy alone is no longer good enough. As new minimally invasive surgical tools are used, the aim is to offer patients improved quality of life in addition to highly effective treatment.
What can be done to improve surgery outcomes?
Development in the field of neurosurgery has made it possible for neurosurgeons to better visualise exactly where the tumour is and to safely access tumours with lesser risks of serious complications. You should discuss the different available surgical options and a tailored treatment plan with your neurosurgeon.
Infographics on surgery for brain tumour and list of top 5 tools to improve outcome. Additional treatments, including chemotherapy, radiation and targeted therapies, may be required as shown. Top 5 tools used by neurosurgeons in Singapore to improve brain tumour surgery treatment:
1. Key-hole approach
Minimally invasive parafascicular surgery (MIPS) is a key-hole surgical approach which employs minimally disruptive tools to gain a safe passage to hard-to-reach tumours. By using the brain’s natural folds and pathways to reach the tumour, it is possible to minimise cutting through and damaging normal brain tissue. Read more about minimally invasive brain surgery.
2. Awake surgery with intraoperative brain mapping
During parts of the procedure, electrical brain stimulation will be used to map out the areas of the brain critical for speech and movement. You will be woken up and asked to read, speak or perform certain movements. The brain maps generated from the real-time testing and feedback will help identify safe zones for the neurosurgeon and guide tumour removal. Read more about awake craniotomy and brain mapping for tumour.
3. Neuromonitoring
Continuously monitoring of brain areas during surgery helps identify the functioning and non-functioning parts of the brain, and to check if the integrity of important brain structures have been affected by the surgery. One of the advantages of intraoperative neurophysiological monitoring (IONM) is that it can be done even when the patient is under general anaesthesia and as an alternative to “awake brain surgery”.
4. Enhanced visualization with microscope & fluorescence
Intraoperative fluorescence is the use of a special dye to demarcate tumour margins from the surrounding brain. The dye (for example 5-ALA or fluorescein) is given to the patient before or during surgery and concentrates within the abnormal brain tumour cells. When viewed through special filters under the neurosurgeon's operating microscope, the tumour becomes fluorescent and appears “glowing” compared to the surrounding normal brain. This helps the neurosurgeon to better visualise and ensure complete brain tumour removal.
5. Computer guided neuronavigation technology
Dedicated navigation software and hardware are used by the neurosurgeon to plan the surgical trajectory and implement it with accuracy in the operating room. Much like the GPS system that are used in cars, the neuronavigation system helps with wayfinding around the MRI brain map, to direct and guide the neurosurgeon to the exact location of the tumour.
Prognosis of brain tumours
The presence of favourable factors improves the prognosis of brain tumours and has been shown to improve overall survival. Brain tumour patients who tend to live longer have:
- Younger age
- Low grade tumours compared to high grade
- Complete surgical removal of tumour
- Presence of molecular tumour markers (we have confirmed that in Singapore patients, MGMT methylation status was linked to improved survival)
Summary
- Brain tumour can occur in any part of the brain
- Removing all of the tumour is the goal
- Preservation of quality of life after surgery is paramount
- Advances in the use of minimally invasive surgery, awake craniotomy and other monitoring and visualisation are key tools that can help achieve this outcome