The Effects of Cannabis on Brain Tumours
Cannabis is increasingly used as a treatment for patients with cancers. Despite promising preclinical data exposing the potential for cannabinoids to help treat GBM (glioblastoma multiforme), an extremely aggressive brain tumour, safety and clinical data are lacking. However, recent trials suggest cannabis may stall brain tumour growth.
Major UK Trial for Oral Cannabis in Brain Tumour Treatments
Glioblastomas are the most aggressive type of brain tumour and also the fastest growing. More than 2,000 people are diagnosed with GBM in the UK and more than 7,000 in the US.
The tumours grow fast with poorly defined boundaries and have tendrils extending into other parts of the brain. These features of GBM tumours make them very challenging to treat, with the average after-treatment survival time just 12 - 18 months.
Almost all GBM tumours recur, even after extensive treatment with chemotherapy, radiotherapy, and surgery.
The last decade has seen increasing interest in cannabinoids as a treatment for relieving the symptoms and improving survival rates.
Phase I trials used cannabinoids to treat laboratory mice with induced brain cancer. Researchers then examined the genes involved with blood vessel growth in the tumour and found that the cannabinoids seemed to inhibit the growth of blood vessels.
The second stage of the study used two human samples taken from glioblastoma patients. Blood vessel growth was lower in both tumour samples after treatment with cannabinoids.
The research requires more study, but early results show promise for cannabinoids used as cancer treatments to help patients who have run out of options.
ARISTOCRAT Study by the Brain Tumour Charity
A cannabis-based drug named Sativex is currently undergoing trials to treat brain tumours, with 15 NHS hospitals taking part after promising results from the phase 1 study.
The phase II trial will focus on discovering whether an oral spray containing THC and CBD can extend the life of patients after being treated for GMB.
The new drug is already used in treatments for multiple sclerosis and was found to be tolerable during chemotherapy while also potentially extending the life of patients in the phase 1 trial.
A new phase II trial will be led by Professor Short at the University of Leeds. The Cancer Research UK Clinical Trials Unit at the University of Birmingham will also be coordinating with the trial to recruit more than 230 patients from all over the UK in early 2022.
A successful trial will mean that Sativex could be one of the first treatments added to the NHS treatment strategy for GMB patients since the introduction of temozolomide chemotherapy. Dr Susan states that these drugs work very well with temozolomide in slowing tumour growth.
Stephen Lee from Leyland in Lancashire participated in the phase I trial after having his tumour removed through surgery. He does not know whether he received the placebo or the real thing but states that the tumour had not returned since 2016, when the trial ended.
Research in using cannabinoids on brain tumours and for cancer treatments is ongoing. However, many clinical trials and significant UK trials of Sativex have revealed promising results in improving and extending the lives of brain cancer patients. The evidence is mounting, but more work needs to be done, so always seek the advice of your doctor when considering any type of cannabis-derived therapy.