Cannabidiol (CBD) is a non-psychoactive cannabinoid increasingly used by cancer patients for symptom management. CBD has been explored in clinical settings for its potential to relieve pain related to cancer or chemotherapy and even to slow tumor progression. This report reviews human clinical research<\/strong> on CBD in cancer care, focusing on two key areas: pain relief<\/strong> (cancer-related pain and chemotherapy-induced pain) and tumor reduction<\/strong> (changes in tumor size or disease progression). Only studies in human patients<\/strong> are included (excluding preclinical animal or cell studies), emphasizing findings from peer-reviewed clinical trials and observational studies. The current evidence is mixed \u2013 some trials suggest benefits in symptom control, while others show no significant improvement, and the anti-tumor effects of CBD in humans remain largely unprovennews.cancerresearchuk.org<\/span><\/span><\/span><\/a><\/span>. Below, we discuss the major findings in each area, followed by a summary table of key studies.<\/p>\n Cancer pain is often severe, and while opioids are the mainstay therapy, a subset of patients experiences refractory pain even on high-dose opioidspubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. CBD and other cannabinoids have been investigated as adjunct analgesics in this context. Several clinical trials have tested CBD-containing medications for managing cancer-related pain:<\/p>\n THC+CBD Extract vs Placebo (Johnson et al., 2010)<\/strong> \u2013 In a landmark multicenter randomized trial<\/strong> of 177 patients with advanced cancer and pain not controlled by opioids, an oromucosal spray containing a 1:1 ratio of \u0394\u2079-tetrahydrocannabinol (THC) and CBD (nabiximols) was compared to THC alone and placebopubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. After 2 weeks, the THC+CBD group had significantly better pain relief than placebo: average pain scores improved more (\u22121.37 vs \u22120.69 on a 0\u201310 scale) and 43%<\/strong> of patients on THC+CBD achieved >30% reduction in pain vs 21%<\/strong> on placebopubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. By contrast, the THC-only group did not differ from placebo (\u224823% responders each)pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. This trial demonstrated that the THC+CBD combination produced clinically meaningful pain reduction in opioid-refractory cancer painpubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>, although mild-to-moderate side effects (e.g. sedation, nausea) were observed more with THC+CBD than placebopubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>.<\/p>\n<\/li>\n Nabiximols in Advanced Cancer Pain (Phase III, 2018)<\/strong> \u2013 A larger Phase III RCT<\/strong> (almost 400 patients) evaluated nabiximols (THC:CBD oromucosal spray) as add-on therapy for advanced cancer pain despite opioidspubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. In this trial, nabiximols did not meet the primary endpoint<\/strong> \u2013 median pain reduction was slightly greater with THC+CBD but not statistically significant versus placebo (\u221210.7% vs \u22124.5%, p<\/em> = 0.085)pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. Some secondary quality-of-life measures favored nabiximols, and post hoc analyses suggested patients on lower opioid doses might benefit morepubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. Overall, however, the high-quality evidence from this and other trials led reviewers to conclude that cannabis-based medicines (including THC+CBD extracts) have no clear clinically relevant benefit in moderate-to-severe cancer pain<\/strong> compared to placebo, aside from individual casespubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. The American Society of Clinical Oncology (ASCO)<\/strong> guidelines currently recommend against routine use of cannabinoids for cancer pain<\/strong> outside of clinical trials, given inconsistent efficacy and known side effectspubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>.<\/p>\n<\/li>\n Pure CBD Oil in Palliative Cancer Care (Hardy et al., 2023)<\/strong> \u2013 To isolate CBD\u2019s effect, a placebo-controlled trial<\/strong> in 144 patients with advanced cancers examined purified CBD oil (without THC) as an adjunct to specialist palliative carepubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. CBD was titrated up to 600 mg per day orally over 28 days. The results showed no significant improvement<\/strong> in pain or overall symptom distress scores compared to placebopubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. By day 14, symptom scores had improved modestly in both groups (due to palliative care), with no difference between CBD vs placebo<\/strong> (58.7% responders on placebo vs 44.8% on CBD, p<\/em> = 0.13)pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. There were also no differences in opioid usage or quality-of-life, and adverse effects were similar in both armspubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. The investigators concluded that CBD oil provided no additional benefit<\/strong> beyond standard care in alleviating cancer symptoms or painpubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. This high-quality trial underscores that pure CBD has not proven effective for cancer-related pain<\/strong> when tested rigorously.<\/p>\n<\/li>\n Recent Developments:<\/strong> Interestingly, very recent data suggest that adding THC might be key to analgesic effects. A 2024 clinical report from an ASCO meeting found that a THC:CBD (1:1) oral cannabis oil<\/strong> did yield a statistically significant improvement in cancer pain versus placebo \u2013 however, this came at the cost of increased psychotropic side effects<\/strong> from THCascopubs.org<\/span><\/span><\/span><\/a><\/span>. This reinforces the notion that THC (with its direct agonism of cannabinoid receptors) is likely the primary driver of pain relief, whereas CBD alone has a more limited analgesic role. Overall, current evidence indicates mixed results<\/strong> for cannabinoid-based pain management in cancer: some patients derive relief, but consistent benefits of CBD (especially in isolation) have not been confirmed in large trialspubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>.<\/p>\n<\/li>\n<\/ul>\n Certain chemotherapy drugs (e.g. platinum compounds, taxanes) cause peripheral neuropathy, leading to tingling, numbness, and neuropathic pain in cancer patients. Preclinical studies suggested CBD might protect nerves or reduce neuropathic pain. Early clinical research has explored CBD for chemotherapy-induced peripheral neuropathy (CIPN):<\/p>\n CBD to Prevent CIPN (Nielsen et al., 2022)<\/strong> \u2013 A Danish pilot study evaluated oral CBD (300\u202fmg\/day)<\/strong> given prophylactically around chemotherapy to prevent acute nerve damagepubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>. Fifty-four patients receiving oxaliplatin-based (for colorectal cancer) or paclitaxel\/carboplatin chemotherapy (for cancers like breast or ovarian) were given CBD oil (150\u202fmg twice daily for 8 days, starting one day before chemo) and compared to a similar cohort without CBDpubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>. Results:<\/strong> Patients who took CBD showed attenuated neurologic symptoms<\/strong> in the first week after chemo \u2013 in the oxaliplatin group, CBD users reported significantly less cold sensitivity and discomfort swallowing cold liquids than controlspubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>. Objective tests of nerve function (vibrometry at 250 Hz) also showed smaller sensory changes<\/strong> in the CBD group, especially in the paclitaxel group, suggesting less nerve impairmentpubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span><\/span>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. No serious side effects emerged, leading authors to conclude CBD appeared to reduce early neuropathy symptoms without major safety issues<\/strong>pubmed.ncbi.nlm.nih.gov<\/span><\/span><\/span><\/a><\/span>. They noted this as preliminary evidence that CBD might protect against chemotherapy-induced neuropathic pain<\/strong>, warranting larger randomized trialsCBD for Pain Relief in Cancer Patients<\/h2>\n
Cancer-Related Pain<\/h3>\n
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Chemotherapy-Induced Pain (Neuropathy)<\/h3>\n
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