Each year, around 14 million people are diagnosed with cancer globally, a figure that is expected to rise to 22 million within the next two decades. Over one-third of people with cancer, and around three-quarters of those with advanced cancer, experience chronic pain. Most cancer pain is caused by tumors pressing on nerves, bones or organs, or it may be related to the cancer treatments themselves, such as chemotherapy and radiotherapy. Other factors such as depression, fear, anxiety and a lack of sleep can also affect pain perception. Treating the pain that crops up as a result of cancer or its treatments is thus an important part of all clinical responses to the disease.
According to researchers at the University of Bristol, United Kingdom, marijuana may provide some benefits for people with cancer-related pain. In a paper published in the Journal of the American Medical Association in June 2015, researchers analyzed information from eight studies that looked at the effects cannabinoids had on patients with nerve and cancer pain. It revealed that patients using cannabinoids were about 40 percent more likely to report a reduction in their pain. Patients who smoked marijuana reported the greatest levels of pain relief.
Currently, opioids are the principal medications employed in the management of cancer pain. However, like all medications, opioid use can come at a cost. Short-term use of opioids can cause side effects such as constipation, drowsiness and nausea, while long-term use is associated with high tolerance, dependence and addiction. Thus, there is a clear and urgent need for treatments that bring pain relief with fewer side effects.
A study by researchers at the University of California San Francisco, found that patients may experience greater relief of pain through the combined use of cannabinoids and opioids. In a paper published in December 2011 in Clinical Pharmacology & Therapeutics, researchers found that patients using cannabinoids and opioids were more likely than patients using opioids alone to report a reduction in pain. The researchers also revealed that a combined approach could result in reduced opioid dosages.
Pain is one of the main side effects of cancer and its treatments, and conventional medications often offer little relief. Medical marijuana provides an alternative, and may ease pain more effectively than standard treatment.