Research is warranted on the potential use of cannabidiol oil as a primary treatment for cancer, say the authors of a new case report published by the BMJ

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Research is warranted on the potential use of cannabidiol (CBD) oil as a primary treatment for cancer, say the authors of a case report that demonstrates tumour regression in a patient with non-small cell lung cancer (NSCLC) who declined conventional treatment and administered CBD daily for 2.5 years.

In BMJ Case Reports, clinicians from Watford General Hospital and the Basildon and Thurrock University Hospitals Foundation Trust report the case of a woman in her 80s who presented to her GP in February 2018 with persistent cough. A chest X-ray carried out at the time was normal and she was treated with a course of oral antibiotics. Despite this, the cough persisted and a repeat chest radiograph in June 2018 showed a lung lesion.

The patient underwent a computed tomography (CT) scan of the chest in June 2018. This showed a lesion in the right middle lobe of her lung measuring 41 mm at its longest axial diameter. A subsequent positron emission tomography scan carried out in July 2018 showed this lesion to be avid with a standardised uptake value maximum of 10.5. She subsequently underwent CT-guided lung biopsy and was diagnosed with NSCLC, not otherwise specified, with a tumour, node, and metastases staging of T2bN0Mx. Gene mutation testing for anaplastic lymphoma kinase gene and epidermal growth factor receptor gene was negative with less than 1% of tumour cells expressing programmed death-ligand 1.

A CT of the head was normal and an endobronchial ultrasound-guided transbronchial needle aspiration of the subcarinal and left lower paratracheal lymph node showed no evidence of metastases.

A repeat CT scan of the chest carried out in September 2018 showed that the right middle lobe tumour had reduced to 33 mm, but there were new bilateral upper lobe nodules measuring 4 mm in the left apex and 6 mm on the right.

The patient declined a lobectomy. She was referred to oncology and repeat CT and PET scans were carried out. These restaging scans showed that her cancer had reduced in size by 11 mm and 18 mm, respectively. The left apical nodule previously seen in the September 2018 CT scan had resolved and the right upper lobe nodule had also reduced in size.

The patient was offered stereotactic ablative radiotherapy, but she declined this treatment as well based on the potential side effects. The decision was made to watch and wait with regular CT surveillance.

CT scans carried out at 3–6-month intervals over the following 2.5 years demonstrated that the primary tumour appeared to be shrinking progressively. The initial 41 mm lesion identified in June 2018 had reduced to 10 mm in February 2021, representing an overall 76% reduction in maximum axial diameter, averaging at a reduction of 2.4% per month.

The patient was contacted in February 2019 to discuss her case, at which point she revealed that she had been self-administering 0.5 ml CBD oil two to three times daily on the advice of a family member since August 2018, shortly after her original diagnosis. The constitution of the oil, which was sourced online from outside the UK, was 19.5% Δ9-tetrahydrocannabinol (THC), 20.05% CBD, and 23.8% tetrahydrocannabinolic acid. There were no other changes to her prescribed medications, diet, and lifestyle, and she had continued to smoke one pack of cigarettes a week throughout the surveillance period.

CBD and THC

CBD and THC are known to interact with the body’s own endocannabinoid system, which is composed of three main parts: cannabinoid receptors (CB1 and CB2), endocannabinoids, and enzymes. The system functions to regulate physiological and cognitive processes, as endocannabinoids act as neuromodulators. They are involved in a variety of processes, including neuronal function, emotion, feeding and energy metabolism, pain and inflammation, sleep, and immune function.

The interactions of CBD and THC with the endocannabinoid system play a role in controlling a cell’s fate by modulating the effects of proteins and nuclear factors that are involved in cell proliferation, differentiation, and apoptosis. This interaction has fuelled research into the potential use of cannabinoids as a direct cancer treatment. To date, studies have shown that cannabinoids can have an effect on tumour growth, development, invasion, metastasis, and angiogenesis; however, the results have been conflicting.

The authors of this case study stress that while there appears to be a relationship between the intake of CBD oil and the observed tumour regression, they are unable to conclusively confirm that the tumour regression was due to the patient taking CBD oil.

They call for more research into the mechanism of action, administration pathways, safe dosages, effects on different types of cancer, and potential adverse side effects of cannabinoids. However, they say, the potential for cannabinoids to be used to augment or replace conventional primary cancer treatments definitely justifies further research.

Commenting on the report, Professor David Nutt, Edmond J Safra Chair in Neuropsychopharmacology at Imperial College London, said: ‘This is one of many such promising single case reports of medical cannabis self-treatment for various cancers. Such case reports are biologically credible given the adaptogenic nature of the endocannabinoid system.

‘A case report itself is not sufficient to give any form of proof that one thing caused the other—we need trials for that. There are some controlled trials already started and more are required to properly explore the potential of medical cannabis in a range of cancers.’

Dr Tom Freeman, Director of the Addiction and Mental Health Group at the University of Bath, also commented on the cannabinoid product used by this patient. ‘The product used by this patient reportedly contained high levels of THC (the intoxicating component of cannabis), and was sourced from outside the UK. This type of product is very different to most CBD oils, which predominantly contain CBD. Unlike prescribed medicines, CBD wellness products lack assurance of quality, safety, or efficacy and should not be used for medicinal purposes.’

This article originally appeared on Univadis, part of the Medscape Professional Network.

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