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✍🏻 Kate Johnson | PhD in Analytical Chemistry
What is a brain tumour? 🧠
A brain tumour is a group of cells that have grown out of control and have formed a mass of cells in a region of the brain.
Usually, cells only divide to make new cells in order to replace old cells. However, cancer begins when a cell divides unnecessarily and continues to divide. This creates a clump of cells called a tumour.
Brain tumours can either be primary brain tumours, which originate in the brain, or secondary brain tumours, which are parts of another tumour that has travelled from elsewhere in the body, and deposited in the brain.
Around 12,300 people are diagnosed with a brain tumour in the UK each year.
What are the current treatment options? 💊
At present, the most common treatment for brain tumours is surgery.
This can be efficient at removing the tumour, however it is a very invasive procedure and can prove difficult or impossible depending on the location of the tumour within the brain.
Other treatment options are radiotherapy and chemotherapy. Radiotherapy is the use of radiation, usually x-rays, to destroy the tumour cells, and is the main treatment option if surgery is not viable. Chemotherapy is the use of drugs to destroy cancer cells, and is the least invasive form of treatment. The most effective chemotherapy drug for brain tumours is temozolomide, however there are other more potent chemotherapy drugs that could be more successful in destroying brain tumours if they were able to cross the blood brain barrier.
What is the blood brain barrier? 🛡
The blood brain barrier is a membrane that protects the brain from harmful substances.
It is a semi-permeable layer of cells that controls what passes from the blood vessels into the brain tissue. This is beneficial to protect the brain from harmful substances, such as toxins and pathogens, however this proves to be a significant problem in the delivery of drugs to the brain. As such, research continues to address this issue, with several recent advances showing promise in certain techniques that allow the transport of chemotherapy drugs through the blood brain barrier in order to destroy brain tumours.
What are the recent advances in treatment? 💡
Breaking through the blood brain barrier is key for the development of less invasive treatment options for brain tumours.
Magnetic helmet
The use of magnets to deliver drugs to a specific site within the body has already shown promise in early clinical studies to treat cancers close to the surface of the body. A drug is attached to magnetic nanoparticles (MNPs) and a magnetic field is created to direct the MNPs to the treatment site.
Brain tumours are more difficult to reach, and so stronger magnets are required, like those used in MRI scanners. Researchers at the University of Sheffield have developed a magnetic helmet with neodymium magnets for mice. They attached MNPs to temozolomide and administered it intravenously to the mice. The results showed that not only was the magnet working and concentrating the MNPs in the tumour, but the tumour significantly reduced in size, and the length of survival increased compared to mice that were administered the same dose of temozolomide on its own.
This proof of concept research shows significant promise in changing the way we treat brain tumours, providing the potential for less invasive treatment options and improved outcomes.
Ultrasound device
Researchers at Northwestern Medicine have applied a skull-implantable ultrasound device to temporarily open the blood brain barrier. It creates a small window of opportunity to allow drugs to pass through the blood brain barrier before the integrity of this membrane is restored just one hour after sonication.
This ongoing phase 2 clinical trial combines the use of an ultrasound device with two strong chemotherapy drugs, paclitaxel and carboplatin, that cannot usually pass through the blood brain barrier. By opening the blood brain barrier with the ultrasound device and administering the chemotherapy drugs intravenously, the concentration of drug in the brain increased by four to six times.
Not only does this show immense progress in the targeted treatment of brain tumours, but this method could also be used in other brain diseases.
Edited by: Olivia Laughton | Content Editor | BSc Microbiology, University of Leeds
