Medical cannabis has attracted much debate worldwide over the last few years especially when it comes to its use for cancer treatment, and in Malaysia since the case of one Muhammad Lukman was sentenced to death for possessing and distributing cannabis and its derivatives.

Two questions arise; is medical cannabis useful for cancer patients, and does it cure cancer?

The discussions on this topic are confined to the science and its application. Aspects of legal, regulatory, social and commercial interest are beyond the scope.

For millennia cannabis, or hemp, has been used in different cultures as herb, folk remedies, and medicinal food. Marijuana, the Mexican similarity, has a recreational drug and narcotic connotation. In Traditional Chinese Medicine, hemp is considered one of the fundamental herbs, having properties as a laxative, sedative, pain relief, nausea, and nervous disorders. The Romans used hemp for earache, stomach disorders, and burns.

Hemp is known as a sacred grass in Ayurveda. The plant was used in Arabic medicine for vomiting, inflammation, epilepsy, fever, and excretion of urine. Across culture and history it has been commonly known for pain relief.

The central issue for the debate on medical cannabis stems from the word, “evidence”.

While cancer patients, their family members and the public generally clamour for the use of cannabis to be decriminalised, officials have been saying there is no evidence or not enough evidence for its use. There is a vast difference in the meaning of the word ‘evidence’ used in common language and that used in the language of science. This is where even healthcare policy makers and some academics fail to fully comprehend.

The word “evidence” derives from the term, evidence-based medicine (EBM). EBM was first introduced in 1992 to incorporate “the best available external clinical evidence from systematic search” so that clinicians may be guided to use the evidence in their practice.

EBM recognises a hierarchy of evidence. Occupying the top is the systematic review and meta-analysis of randomised control trials (RCT), recognised as the gold standard.

Occupying the bottom rungs is the observational studies, case series and case reports, which are not considered for evidence in EBM. Results of non-RCT studies will not be accepted as evidence.

A clinical study to provide evidence in medical cannabis has to start from small. It has to begin with case reports, case series or other pilot and observational studies that inform. Even anecdotal reports about apparent benefits are valuable in the beginning. Obtaining the ethics approval is a must prior to conducting the RCT. RCT is usually conducted with large numbers of subjects. There has to be a certain number needed to treat (NNT) in order to achieve statistically significance of the results. Besides being expensive, it is not just any researcher who can conduct a RCT.

Over the last fifteen years, in vitro and in vivo cancer studies have shown that cannabidiol (CBD) and tetrahydrocannabinol (THC) have the ability to instigate apoptosis, inhibit angiogenesis, proliferation and metastasis of certain types of cancer cells. The discovery of the endocannabinoid (EC) system in mid 1990s by Dr Ralphael Mechaoulam, that explained the mechanism how cannabinoids bind to receptor proteins and therefore starts a cascade of intracellular signalling process, helped other researchers make scientific breakthroughs in the mid 2000s.

Incidentally, phytocannabinoids such as CBD and THC from cannabis are also attracted to the receptor sites for cannabinoids produced naturally in the human body. With the mechanism explained, the floodgate is now open for clinical cancer research and eventual RCTs.

In reality, few, other than the pharmaceutical industry, have the capacity to conduct RCTs. But why should the industry do so if the treatment agent is non-patentable, and if found efficacious will be detrimental to its core business? Dr Whiting and colleagues in their systematic review and meta-analysis in 2015 provided moderate-quality evidence, indicating cannabinoids may be beneficial for treatment of chronic neurological and cancer pain, for multiple sclerosis, and for reducing frequency of convulsive seizure in epilepsy. Such findings are recognised as evidence in EBM.

Answers to the earlier two questions. Yes, it is useful as an adjunct to conventional cancer treatment. No, scientifically there is no evidence that shows cannabis can cure cancer. The word cure in cancer should be avoided. In cancer therapy there is no stand-alone protocol. Treatment protocol should preferably be a combination of all known efficacious approaches, including both conventional and non conventional. A holistic approach is necessary. – October 11, 2018.

* Captain Dr Wong Ang Peng is a researcher with an interest in economics, politics, and health issues. He has a burning desire to do anything within his means to promote national harmony. Captain Wong is also a member of the National Patriots Association.

* This is the opinion of the writer or publication and does not necessarily represent the views of The Malaysian Insight. Article may be edited for brevity and clarity.