Marijuana Offers No Relief For Cancer Pain: New Study Finds

The use of cannabis-based medicines for managing pain and symptoms in adults with cancer has gained significant attention in recent years. Researchers have conducted numerous studies to evaluate the effectiveness and potential drawbacks of medical cannabis in comparison to placebos and other established analgesics. A recently published study has found that cannabis offers no pain relief for cancer pain, contradicting past evidence. 

To gather comprehensive data, rigorous search methods were employed, following Cochrane standards. The most recent search was conducted in January 2023. The selection criteria focused on double-blind randomized controlled trials (RCTs) that involved medical cannabis, both plant-derived and synthetic forms, compared to placebos or other active treatments for cancer pain in adults. The trials encompassed various treatment durations and included at least 10 participants per treatment group.

A total of 14 studies involving 1823 participants were identified. While none of the studies specifically evaluated the proportions of participants reporting no worse than mild pain after treatment initiation, several interesting conclusions were drawn from the available data.

• Oromucosal nabiximols (a combination of tetrahydrocannabinol [THC] and cannabidiol [CBD]) or THC alone were assessed in five RCTs, involving 1539 participants who experienced moderate to severe pain despite opioid therapy. The evidence suggests that both oromucosal nabiximols and THC are ineffective in relieving moderate-to-severe opioid-refractory cancer pain, with moderate certainty.
• Nabilone, another cannabis-based medicine, was found to be ineffective in reducing pain associated with (radio-) chemotherapy in individuals with head and neck cancer and non-small cell lung cancer. However, the evidence supporting this conclusion is of low certainty.
• Synthetic THC analogues, when administered as a single dose, did not demonstrate superiority over a low-dose morphine equivalent in reducing moderate-to-severe cancer pain, with low-certainty evidence.
• Additionally, CBD did not provide added value when used in conjunction with specialist palliative care alone for pain reduction in people with advanced cancer, according to low-certainty evidence.

The researchers concluded that the current evidence suggests limitations in the effectiveness of oromucosal nabiximols, THC, nabilone, synthetic THC analogues, and CBD for certain aspects of pain relief in cancer patients. They therefore recommended further well-designed studies, including randomized placebo-controlled trials, to expand our understanding of the potential benefits and drawbacks of cannabis-based medicines in managing cancer-related pain. These results seem to contradict earlier studies such as this.