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expert reaction to case report of woman with lung cancer who used cannabidiol oil

A case report published in BMJ Case Reports follows a patient who declined conventional treatment and took ‘CBD oil’ as an alternative self-treatment for her lung cancer.


Prof David Nutt, The Edmond J Safra Chair in Neuropsychopharmacology, 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.”


Prof Edzard Ernst, Emeritus Professor of Complementary Medicine, University of Exeter, said:

“Cannabinoids have been shown to reduce the size of prostate cancer tumours in animal models.  Previous case reports have yielded encouraging findings also in human cancers.  However, case reports cannot be considered to be reliable evidence, and there are currently no data from rigorous clinical trials to suggest that cannabis products will alter the natural history of any cancer.”


Dr Tom Freeman, Senior Lecturer and Director of the Addiction and Mental Health Group, University of Bath, said:

“These results are exciting and very encouraging for this patient.  However as a single case study the quality of scientific evidence is low and should not be used to change clinical practice.  People with lung cancer should always seek guidance from a healthcare professional when deciding on an appropriate treatment.

“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.”



‘Lung cancer patient who had declined conventional cancer treatment: could the self-administration of ‘CBD oil’ be contributing to the observed tumour regression?’ by Kah Ling Liew et al. was published in BMJ Case Reports at 23:30 UK time on Thursday 14 October 2021.

DOI: 10.1136/bcr-2021-244195



Declared interests

Prof David Nutt: “DJN chairs the scientific committee of the charity Drug Science that receives unrestricted educational grants from some medical cannabis companies.”

Prof Edzard Ernst: “No conflicts of interest.”

Dr Tom Freeman: “No conflicts of interest to declare.”



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