Cutting-Edge Treatment for Brain Tumour
According to NHS England, the number of patients benefiting from state-of-the-art brain tumour treatments will double to 6,200 by 2019, as access to advanced forms of robotic radiosurgery is set to increase.
This follows the recognition that the technology is currently available at only a few specialised centres, despite their potential to improve quality of life and outcomes for patients.
Cyberknife and Gamma Knife Treatments
Examples of robotic radiosurgery are the cyberknife and gamma knife systems. Both use external radiation to destroy cancer cells inside the brain without the need of an operation.
The systems enable doctors to deliver extremely high doses of radiation directly to the tumour, from many different angles and with outstanding precision.
This is an important advantage over conventional radiotherapy methods, in that it allows to target the cancer more effectively while minimising the risk of damage to healthy tissue.
Cyberknife and gamma knife differ in several ways. For example, with the cyberknife system radiation beams are delivered by a robotic device that moves around the patient, who lies on a treatment couch.
Patients who receive gamma knife treatment must have a metal frame applied to their head and lie into a machine similar to an MRI scanner. While cyberknife systems can target a tumour from more that 1,300 different positions, only 190 positions are possible for gamma knife systems.
Electric Tumour-Treating Fields Technology
An advantage of the above treatments is that patients are usually in and out of hospital on the same day. But scientists have gone a step further, and developed a device that delivers treatment non-invasively, for up to 18 hours a day, while patients go about their normal activities.
The technology works by sending low-intensity electric fields to the brain. These are generally referred to as tumour-treating fields, or TTFs. They originate from a small electric field generator that fits into a backpack, and travel to a set of adhesive patches on the patient’s head. From here, they are delivered to the brain area where the tumour is located.
The idea is that the electric fields will stop cancer cells from multiplying, and also destroy some of them, without affecting those that are healthy.
The technology could be of particular benefit to patients with glioblastoma (GBM) – one of the most aggressive brain tumours. In a clinical trial of GBM patients, treatment with TTFs and temozolomide (a chemotherapy drug for brain tumour) was more effective than chemotherapy alone.
Adding TTFs to temozolomide almost doubled progression free survival, the time during or after treatment in which the tumour does not get worse. This increased from 4.0 to 7.1 months.
Overall survival also improved, from 15.6 months with temozolomide alone, to 20.5 months with TTF plus temozolomide.
Genomics-Guided Personalised Treatment
The team, from Yale School of Medicine, Connecticut, used a method called longitudinal genomic profile. They looked at changes in the genetic make-up of the cancer, after each treatment the patient received.
For example, the researchers did a genetic analysis after the tumour was surgically removed, and after chemotherapy. At every genetic analysis, they designed a therapy for the particular genetic make-up they found.
The last genetic analysis revealed that the patient’s cancer had 30 times more mutations than when it was originally removed, and was a good target for immunotherapy with pembrolizumab – a PD-1 checkpoint inhibitor.
Treatment with pembrolizumab led to a decrease in the size of the tumour, which then remained stable for several months.
Dr. Zeynep Erson Omay, who led the study, said in a press release: The “findings have significant implications for precision treatment of these tumors.” And we may “soon start to see real changes in patient outcomes.”
Emerging Immunotherapy Drugs
“Immunotherapy itself is raising hopes in the treatment of glioblastoma,” adds Jonathan Furst, CEO at Alivia Swiss Health UK. “To date, no drug therapy approved for this brain cancer has been able to substantially extend patient survival. But scientists are now working to improve this scenario, through the development of new therapies that stimulate the immune system to recognise, attack and destroy cancer cells.”
Among these are the checkpoint inhibitors nivolumab and ipilimumab. Their efficacy and safety is currently being tested in a phase III clinical trial, whose results are expected in January 2018.
Immunotherapy vaccines are set to make a difference, too.
For example, researchers from the Ann & Robert H. Lurie Children’s Hospital of Chicago, Illinois, are investigating one called HSPPC-96, which has been developed for the treatment of newly diagnosed paediatric glioblastoma.
They are currently recruiting patients for a phase I study.
Another promising immunotherapy approach involves the use of so-called super-charged T-cells.
T-cells are a type of white blood cells. They are taken from the patient and genetically engineered in the lab, to improve their ability to find cancer cells.
They are then allowed to multiply into the billions, and reintroduced into the patient where they can launch a massive attack on the tumour.
Scientists are recruiting patients for a phase I/II clinical trial that aims to assess the efficacy of this immunotherapy in malignant glioma – the most common type of malignant brain tumours.