By Dr. Laura Tennant
Ancient cultures across the globe used Cannabis sativa for a variety of medicinal and recreational purposes and many examples have been discovered by archaeologists and historians during the examination of ancient documents and artefacts. For example, the Ancient Egyptian Ebers Papyrus is one of the most complete preserved medical documents, dating back to the eighteenth century BC. It documents the ingredients and preparation of medicinal remedies used by the ancient Egyptians and includes a number of recipes containing Cannabis sativa for ailments including inflammation and pain. In Ancient China, legend has it that the Emperor Shen Neng (c. 2737 B.C) prescribed teas made from medicinal cannabis for a variety of illnesses and the first documented use of cannabis as an analgesic was recorded in 140-208 in China by the surgeon Hua Toa, who gave his patients powdered extracts of the plant combined with wine prior to surgery.
In the context of cancer, whilst the prescribed use of medicinal cannabis for cancer is relatively new to Oncologists in current times, its origins date back thousands of years. In 1993, the mummified remains of a young woman, estimated to be at least 2,500 years old, were found in the Altai Mountains of Siberia. Amongst the items placed in her burial chamber, archaeologists found a pouch of Cannabis, known to be used as an analgesic in ancient times. Further investigation of the remains by MRI revealed that the woman had been suffering from advanced metastatic breast cancer and so the researchers hypothesize that the woman used cannabis to provide relief from the pain and symptoms of her illness.
Today´s Clinical Practise
The Pharmaceutical industry are developing drugs based on active components of Cannabis sativa and two drugs are currently approved in several countries for cancer related pain: Drobinol (synthetic Δ9-tetrahydrocannabinol -THC- the most psychoactive cannabinoid found in cannabis) and Sativex (a blend of the leaf and flower of two strains of cannabis, cultivated with controlled proportions of THC and Cannabidiol). Not surprisingly, most of the clinical trial evidence supporting the use of cannabis for cancer patients comes from the development process of these drugs rather than from trials with the botanical and since clinicians rely heavily on clinical trial data, some remain sceptical about the efficacy of medicinal cannabis.
This year, in two peer-reviewed publications directed at medical professionals, Oncologist Dr D.I. Abrams at the University of San Francisco made a compelling argument for the inclusion of medicinal cannabis in modern clinical cancer care protocols. He argued that whilst the evidence from clinical trials of the botanical in controlled conditions often lacking or inconclusive, experience from clinical practise clearly demonstrates that it helps patients coping with cancer and improves their quality of life. In particular he supports the use of medicinal cannabis for relief from chemotherapy-induced neuropathic pain, insomnia, nausea and loss of appetite when conventional treatments have failed and when side effects of pharmaceutical outweigh the benefits of the drugs. To access the publications, click the following link.
What does the future hold?
Given the evidence from clinical practice, there is a clear need for data from extensive clinical studies of medicinal cannabis to support its use in cancer patients for alleviating the symptoms associated with cancer. However, the botanical may hold the key to more than just symptomatic relief. There is a growing body of evidence from pre-clinical research in cell and animal models that suggest that some of the active components of cannabis may have direct anti-tumour activity. For example, in laboratory studies of glioma cells, cannabinoids were shown to induce cell death (apoptosis) and stop cell growth (proliferation). These activities were also observed in rat and mouse models and reductions in tumour sizes were recorded. The complex molecular mechanisms behind the cannabinoid activity are still being unravelled, although the CB1 receptor is thought to be involved. This research is now advancing towards clinical studies (see publication). There are several other examples of exciting preclinical data in other tumour types; the research is reviewed in detail in the following publication. This research is still at early stages and needs to be translated into humans, however, the future of cannabis in the field of Oncology certainly looks promising.