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Cannabis and Cannabinoids (PDQ®)

Health Professional Version
Last Modified: 03/25/2014

Changes to This Summary (03/25/2014)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.


Revised text to state that by federal law, the possession of Cannabis, also known as marijuana, is illegal in the United States; however, a growing number of states and the District of Columbia have enacted laws to legalize its medical use.


Added text to state that spasticity is a common symptom of multiple sclerosis for which existing therapy is unsatisfactory and may include muscle stiffness, reduced mobility, and pain; in Canada, New Zealand, and some countries in Europe, nabiximols (a delta-9-tetrahydrocannabinol:cannabidiol extract) is approved for the treatment of spasticity associated with multiple sclerosis via oromucosal administration (cited Zajicek et al. as reference 14 and Howard et al. as reference 15).

Laboratory/Animal/Preclinical Studies

Added Cridge et al. as reference 14.

Human/Clinical Studies

Added text about a pooled analysis of nine case-control studies from the U.S./Latin American International Head and Neck Cancer Epidemiology (INHANCE) Consortium that included information from 1,921 oropharyngeal cases, 356 tongue cases, and 7,639 controls; compared with those who never smoked Cannabis, Cannabis smokers had an elevated risk of oropharyngeal cancers and a reduced risk of tongue cancer (cited Marks et al. as reference 9).

Added text about a randomized, placebo-controlled, crossover pilot study of nabiximols in 16 patients with chemotherapy-induced neuropathic pain that showed no significant difference between the treatment and placebo groups; however, a responder analysis demonstrated that five patients reported a reduction in their pain of at least 2 points, suggesting that a larger follow-up study may be warranted (cited Lynch et al. as reference 40).

This summary is written and maintained by the PDQ Cancer Complementary and Alternative Medicine Editorial Board, which is editorially independent of NCI. The summary reflects an independent review of the literature and does not represent a policy statement of NCI or NIH. More information about summary policies and the role of the PDQ Editorial Boards in maintaining the PDQ summaries can be found on the About This PDQ Summary and PDQ NCI's Comprehensive Cancer Database pages.