Research study · Supportive Care in Cancer · 2025
Medicinal Cannabis for Symptom Control in Advanced Cancer: A Randomised, Placebo-Controlled Trial of 1:1 THC and CBD
Verified on PubMed Randomized controlled trial
A 2025 randomized controlled trial in Supportive Care in Cancer tested medicinal cannabis in cancer. Overall symptom distress improved in both groups by a similar amount, with no difference between them. An honest negative result on the headline question.
In plain language
Study overview
A placebo-controlled trial asking whether a 1:1 THC:CBD oil eased the overall symptom burden of advanced cancer beyond what palliative care already provides.
Findings
Overall symptom distress improved in both groups by a similar amount, with no difference between them. Pain scores improved more on cannabis, but with more psychological side effects, and general wellbeing favoured placebo.
The deeper readScientific analysis
144 patients with advanced cancer were randomised to a 10 mg/ml 1:1 THC:CBD oil or placebo, with the dose escalated over 14 days according to tolerance and continued to day 28. Symptoms were scored on the Edmonton Symptom Assessment Scale and summed into a total symptom distress score.
On the primary outcome - change in total symptom distress at day 14 - both arms improved and neither did better: -6.30 (SD 12.3) on cannabis versus -6.98 (SD 12.56) on placebo (P = 0.76). That both arms improved substantially is itself worth noting, and points at how much good palliative care and trial participation deliver on their own.
Among secondary outcomes, ESAS pain improved more on cannabis (-1.42 versus -0.46; P = 0.04), and both global impression of change and the pain component of quality of life favoured cannabis. The authors attribute the pain benefit to a cost: greater psychomimetic toxicity. General wellbeing improved more on placebo.
The paper
Citation
Hardy JR, Greer RM, Pelecanos AM, Huggett GE, Kearney AM, Gurgenci TH, et al. Medicinal Cannabis for Symptom Control in Advanced Cancer: A Randomised, Placebo-Controlled Trial of 1:1 THC and CBD. Supportive Care in Cancer (2025). PubMed 40705150 · DOI
Read the abstract as published
PURPOSE: Patients with cancer commonly access cannabis hoping to relieve their symptoms. This study assessed whether a 1:1 10 mg/ml THC:CBD combination oil could improve total symptom burden in patients with advanced cancer over that provided by palliative care alone.
METHODS: Participants were randomised to medicinal cannabis (MC) or placebo oil; dose escalated over 14 days according to tolerance and efficacy and continued to day 28. Symptoms assessed using the Edmonton Symptom Assessment Scale (ESAS) were summated to give a total symptom distress score (TSDS). The primary outcome measure was the change from baseline in TSDS at day 14. Secondary outcomes included individual symptom scores, opioid use, participant-selected dose, QoL, psychological symptoms, global impression of change (GIC), and adverse effects.
RESULTS: The pre-planned sample size of 120 at day 14 was reached following the randomisation of 144 patients. Mean (SD) TSDS improved over time in both arms (- 6.30 (12.3) MC, - 6.98 (12.56) placebo, p = 0.76) to day 14 with no difference between arms. A statistically significant improvement in ESAS pain scores in the MC arm (mean (SD) - 1.42 (2.15) MC and - 0.46 (2.83) placebo, p = 0.04) was at the expense of greater psychomimetic toxicity. Improvement in general well-being was greater for the placebo. GIC and the pain component of QoL both favoured MC.
CONCLUSIONS: Patients can be informed that a 1:1 THC:CBD combination cannabis oil was no better than palliative care alone in palliating symptoms in patients with advanced cancer. A small benefit in pain control was associated with greater toxicity.
TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry (ANZCTR): ACTRN12619000037101, 14/01/2019.
Abstract text as indexed by PubMed for this identifier.
In practice
Why this matters
An honest negative result on the headline question. It is a useful corrective: people often arrive hoping cannabis will lift everything at once, and this trial says that is not what happened.
Browse related research
Condition: Cancer Topic: CBD Topic: Medical cannabis Topic: THC
Related on CED Clinic
Back to Daily Research and Patient Questions
Reviewed by Dr. Caplan on September 17, 2026.
This page is general education about a published study. It is not medical advice and does not create a doctor-patient relationship. For care specific to you, book a consultation.
