Reference citations in some PDQ cancer information summaries may include links to external websites that are operated by individuals or organizations for the purpose of marketing or advocating the use of specific treatments or products. These reference citations are included for informational purposes only. Their inclusion should not be viewed as an endorsement of the content of the websites, or of any treatment or product, by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board or the National Cancer Institute.
No ongoing clinical trials of Cannabis as a treatment for cancer in humans were identified in a PubMed search. The only published trial of any cannabinoid in patients with cancer is a small pilot study of intratumoral injection of delta-9-THC in patients with recurrent glioblastoma multiforme, which demonstrated no significant clinical benefit.[25,26] In a trial (NCT02255292) conducted in Israel, oral CBD was investigated as a single salvage agent for recurrent solid tumors. The study was projected to be completed in 2015; however, no results have been published. A small exploratory phase IB study was conducted in the United Kingdom that used nabiximols, a 1:1 ratio of THC:CBD in a Cannabis-based medicinal extract oromucosal spray, in conjunction with dose-dense temozolomide in treating patients with recurrent glioblastoma multiforme.[Level of evidence: 1iA] Of the 27 patients enrolled, 6 were part of an open-label group and 21 were part of a randomized group (12 treated with nabiximols and 9 treated with placebo). Progression-free survival at 6 months was seen in 33% of patients in both arms of the study. However, 83.3% of the the patients who received nabiximols were alive at 1 year compared with 44.4% of the patients who recieved placebo (P = .042). The investigators cautioned that this early-phase study was not powered for a survival endpoint. Overall survival rates at 2 years continued to favor the nabiximols arm (50%) compared with the placebo arm (22%) (these rates included results for the 6 patients in the open-label group who received nabiximols).
Despite its designation as having no medicinal use, Cannabis was distributed by the U.S. government to patients on a case-by-case basis under the Compassionate Use Investigational New Drug program established in 1978. Distribution of Cannabis through this program was closed to new patients in 1992.[1-4] Although federal law prohibits the use of Cannabis, Figure 1 below shows the states and territories that have legalized Cannabis use for medical purposes. Additional states have legalized only one ingredient in Cannabis, such as cannabidiol (CBD), and are not included in the map. Some medical marijuana laws are broader than others, and there is state-to-state variation in the types of medical conditions for which treatment is allowed.
Changes to the summaries are made through a consensus process in which Board members evaluate the strength of the evidence in the published articles and determine how the article should be included in the summary.
(Refer to the Cannabis section in the PDQ summary on Nausea and Vomiting Related to Cancer Treatment for more information.)
Cannabidiol, also known as CBD, is one of many chemicals found in the cannabis plant. It has been touted in some online forums as an alternative treatment, and even a cure, for many illnesses, including cancer. And, some people with cancer say that CBD has helped them as a complementary therapy in managing their symptoms and side effects from standard cancer treatment.
Studies to answer this question are underway. Some scientists are studying whether CBD could relieve some of the side effects of cancer and its treatment, such as pain, insomnia, anxiety, or nausea. Other scientists are studying whether CBD could potentially slow or stop the growth of cancer.
What is CBD?
CBD is 1 of the hundreds of chemicals found in the flowering cannabis plant. CBD does not have the psychoactive, or mind-altering, effects of another chemical found in cannabis called tetrahydrocannabinol (THC). THC is the chemical that causes people to experience a “high.” CBD, on the other hand, is being used by some to help ease pain, anxiety, and sleep issues.
You may also be wondering if CBD is legal in your area. Some states allow the sale and possession of cannabis, including CBD and THC, for medical and recreational use. Others have stricter regulations, so state-by-state laws should always be learned before transporting CBD across state lines. Things are more complicated at the federal level. In 2018, the U.S. government recognized that hemp can be grown and manufactured legally as part of the Farm Act. Hemp can be used to make things like rope and clothing, in addition to CBD oil. In other words, hemp is no longer a controlled substance, which means it is not regulated by the government. This means that consumers have to evaluate the safety and quality of CBD products on their own. Some CBD, for example, may have much higher levels of THC than what is labeled.
To date, no large-scale studies have shown CBD to have benefits for the treatment of people with cancer. Most studies that have been done evaluating CBD as a cancer treatment were in mice or in human cells in the lab. For instance, there are some studies that have shown that CBD inhibits the growth of cancer cells in mice with lung cancer or colon cancer. Another study showed that CBD, together with THC, killed glioblastoma cancer cells in the lab. However, no studies have been conducted in people with cancer.