The Evidence on Cannabinoids for Cancer Symptoms and Potential Anti-Tumor Effects | Research

The takeaway

A comprehensive review found THC and THC/CBD combinations modestly reduce cancer pain, dronabinol and nabilone are effective antiemetics (though superseded by newer drugs), and preclinical data suggest cannabinoids may have anticancer activity through multiple mechanisms.

Cancer patients and oncologists evaluating the evidence for cannabinoids in cancer care.

Both cannabinoid receptor agonists and antagonists showed antitumor activity in preclinical studies

What the researchers found

This review from the National Comprehensive Cancer Network examined cannabinoids across multiple cancer-related applications.

For pain, multiple studies (mostly moderate to low quality) showed that THC and THC/CBD combinations modestly reduce cancer pain. For chemotherapy-induced nausea, dronabinol and nabilone were better than some older antiemetics but have largely been superseded by newer drugs (neurokinin-1 receptor antagonists and olanzapine). Both cannabinoids are recommended for breakthrough nausea among other options.

Dronabinol was ineffective for cancer-related appetite loss but did improve taste disturbances (dysgeusia). Preclinically, multiple cancers express cannabinoid receptors (correlated with tumor grade), and both cannabinoid agonists and paradoxically antagonists showed antitumor activity through apoptosis, anti-angiogenesis, and metastasis inhibition.

The review warned that smoked cannabis may contain Aspergillus fungus, posing infection risk to immunocompromised cancer patients.

Why it matters

This review from a major cancer network provides a balanced, evidence-graded assessment of where cannabinoids fit in cancer care, distinguishing between supported uses (antiemetic, modest pain relief) and unproven claims (direct anticancer effects).

The numbers in context

THC/CBD modestly reduces cancer pain (moderate-low quality studies). Dronabinol ineffective for anorexia but improves dysgeusia. Cannabinoid receptors expressed in proportion to tumor grade. Both agonists and antagonists show preclinical antitumor activity.

How the study worked

Comprehensive clinical review published in the Journal of the National Comprehensive Cancer Network, examining evidence across pain, nausea, appetite, and potential anticancer effects.

What this study cannot tell us

Most pain studies were moderate to low quality. Few randomized trials used smoked or vaporized cannabis in cancer patients. Preclinical anticancer findings have not been confirmed in human trials. The Aspergillus contamination risk applies specifically to smoked cannabis.

How to read the evidence

Review from NCCN synthesizing evidence of varying quality, with pain evidence mostly moderate-low and anticancer evidence limited to preclinical studies.

When this study was published

Published in 2016. The evidence base for cannabinoids in cancer care continues to grow slowly.

The bigger picture

This review highlights an important paradox in cannabinoid cancer research: both activating and blocking cannabinoid receptors have shown antitumor effects in preclinical models. This complexity suggests the relationship between cannabinoids and cancer biology is more nuanced than a simple "cannabis kills cancer" narrative.

Questions still open

How can both cannabinoid agonists and antagonists have antitumor effects? Will clinical trials confirm the preclinical anticancer findings?

Common questions

Should cancer patients use cannabis?

The evidence supports modest benefits for cancer pain and nausea/vomiting. The review noted that for nausea, cannabinoids have largely been superseded by newer, more effective medications. Direct anticancer effects remain unproven in humans. Immunocompromised patients should be cautious about smoked cannabis due to Aspergillus contamination risk.

Can cannabis cure cancer?

There is no clinical evidence that cannabis cures cancer. Preclinical studies show interesting anticancer effects, but these have not been confirmed in human trials. Paradoxically, both activating and blocking cannabinoid receptors showed antitumor activity in lab studies, suggesting the biology is complex.

Read the original research

Cannabinoids for Symptom Management and Cancer Therapy: The Evidence.

Journal of the National Comprehensive Cancer Network : JNCCN, 14(7), 915-22

View on PubMed ↗

Citation

Davis, Mellar P. (2016). Cannabinoids for Symptom Management and Cancer Therapy: The Evidence.. Journal of the National Comprehensive Cancer Network : JNCCN, 14(7), 915-22.