Could cannabis oil shrink lung cancer?

Does cannabis help treat cancer? It is a question that has been hotly debated for decades. Proponents of cannabis on one side claim it does, while others claim there is no medical evidence to suggest otherwise. However, a recent article in the October 2021 edition of the British Medical Journal (BMJ), examines a curious case of a patient who declined conventional lung cancer treatment and chose to self-administer cannabidiol.

Lung cancer is the second most common cancer in the UK and the modern conventional treatments include; surgery, chemotherapy, radiotherapy, immunotherapy and targeted cancer drugs. Despite advances in cancer treatments, the survival rates for lung cancer remain low, at around 15% at 5 years after diagnosis. The average time that it is expected for somebody who declines treatment to live after a diagnosis is 7.5 months.  

The patient presented in the BMJ case study is a lady in her 80’s that went to the doctor with a persistent cough, and after an investigation that included scans was diagnosed with non-small cell lung cancer. The patient has a background of mild chronic obstructive pulmonary disease and is a current smoker who has been smoking a pack of cigarettes a day for 68 years.

After extensive talks with her clinicians where she was presented with information regarding all the likely outcomes, the patient declined radiotherapy on the basis that she watched her late husband suffer from the side effects, she also declined a lobectomy. Doctors decided to place the patient under what is known as ‘watch and wait’ surveillance.

Without the knowledge of her doctors, she decided to take CBD oil two to three times a day. Her doctors continued to monitor her with regular CT scans, and over 2.5 years they observed that the lung cancer was shrinking progressively from the initial size of 41 mm in June 2018, to 10 mm in February 2021. An overall reduction of 76% in maximum axial diameter, which is an average of 2.4% per month over the 2.5 year period.

Her case was brought to the local multidisciplinary team (MDT) in February 2019 when doctors were surprised to see the reduction in tumour size considering she had declined conventional treatment. It was at this point that the lady admitted to taking 0.5 ml of CBD oil orally consistently 2-3 times a day, on the suggestion of a family member. The supplier of the unlicensed treatment advised the clinical team that the main ingredients were THC at 19.5%, CBD at 20.05% and THCA at 23.8%. 

The supplier also revealed that he had advised the patient not to take the medicine with hot food or drinks as it could result in her “feeling stoned”. The patient reported to doctors that she had a reduced appetite since taking the CBD oil. She stated that there were no other changes to her diet or lifestyle, including that she declined to stop smoking tobacco totally instead dropping down to one pack a week. 

​​The report states, “We are aware of the limitations of this case report. We are unable to confirm the full ingredients of the ‘CBD oil’ that the patient was taking or to provide information on which of the ingredient(s) may be contributing to the observed tumour regression. Although there appears to be a relationship between the intake of ‘CBD oil’ and the observed tumour regression, we are unable to conclusively confirm that the tumour regression is due to the patient taking ‘CBD oil’.

“Existing cancer treatments could have severe side effects, both physically and mentally. This is why our patient decided on non-conventional self-treatment. The limited number of case reports appear to show that ‘CBD oil’ can have positive effects on tumour reduction. More research is needed to identify the actual mechanism of action, administration pathways, safe dosages, its effects on different types of cancer and any potential adverse side effects when using cannabinoids. The potential for cannabinoids to be used as an alternative to augment or replace conventional primary cancer treatments definitely justifies further research.”

The potential for cannabinoids to be used as an alternative to augment or replace conventional primary cancer treatments definitely justifies further research.

While the results are encouraging, specialists were quick to issue caution. Professor David Nutt, the esteemed neuropsychopharmacologist who specialises in the research of drugs that affect the brain, gave his opinion to the Science Media Centre, “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.”.

The results of this case study are both interesting and exciting, but it is worth noting that they are based on a single-person case study of which no solid conclusion should be made. The scientific details of the ingredients in the patient’s medicine are not completely known, nor is the schedule of her self-administration. All lung cancer patients are strongly advised to speak with their doctors before commencing any treatment.