CBD and Cancer: Benefits and Dosage
Can CBD treat cancer? No CBD or cannabis product is FDA-approved to treat cancer. The use of cannabis as a medicine dates back at least 3,000 years, according to the National Cancer Institute, and it entered Western medicine in 1839. It was largely prohibited in the United States from the 1930s, and beginning in 1996, states began legalizing cannabis for medical use. Today a growing number of states and the District of Columbia allow medical use, and some also allow adult use.
Since cannabis has been long known to be a medicine, researchers have turned to it in research to see if it can benefit those with cancer. So far, evidence that CBD acts against cancer comes mainly from lab and animal studies, and the FDA warns that CBD can injure the liver and change how other medicines work. Although the Food and Drug Administration has not yet approved cannabis as a treatment for cancer, many Americans are asking their physicians regarding the effects that cannabis can have on cancer and the symptoms it produces.
What is Cancer?
Rather than being one disease, cancer is the name for more than 100 diseases, caused by both genetic and outside factors. In humans, our cells grow old and die. The body begins producing replacement cells. When cancer develops, abnormal cells, which include old and damaged cells, survive. Some of these cells keep dividing without stopping and can spread into nearby tissue, forming growths called tumors that can start almost anywhere in the body.
Without treatment, cancer is unlikely to go away on its own. While treatments can vary depending on the kind of cancer, many of the treatments are similar. They also can produce symptoms that are similar to, and in many cases, worse than, cancer itself.
Cannabis and Cancer Treatment Research
Cannabis has several compounds known as cannabinoids. Two of these cannabinoids have received much attention as treatments for numerous ailments: tetrahydrocannabinol (THC) and cannabidiol (CBD). Cancer is no exception: THC slowed tumors in some mouse studies but sped tumor growth in others, so researchers are also studying CBD, which is not intoxicating.
Only a few small human studies exist, mostly in brain tumors, so most evidence for CBD still comes from lab and animal studies of these effects:
- Antitumor effects
- Antiemetic effects
- Appetite stimulation
- Analgesia
- Anxiety and sleep
Anti-tumor Effects
An in vitro study of the effect of CBD on breast cancer cells showed that CBD induced programmed cell death. CBD inhibited the survival of both kinds of breast cancer cells; estrogen receptor-positive and estrogen receptor-negative breast cancer cells, while having no effect of non-malignant breast tissue.
Another study showed that CBD showed a chemopreventive effect in mice models of colorectal cancer. Further, in studies regarding in vitro colorectal cancer cells, it was discovered that CBD protected DNA from oxidative damage, increased endocannabinoid levels, and reduced cell proliferation.
Antiemetic Effects
In a 2004 study in house musk shrews, THC suppressed vomiting more at higher doses, while CBD suppressed it at low doses and made it worse at high doses.
Appetite Stimulation
With nausea that comes with both cancer itself and the various medicinal treatments for the condition, maintaining a healthy weight can be difficult for patients. CBD alone has not been shown to increase appetite; the appetite evidence is for THC and dronabinol, and in one large trial megestrol acetate worked better than oral THC.
Analgesia
Pain is another symptom suffered by cancer patients, stemming from both cancer itself and the treatments offered for the condition. Cannabis has been used for its analgesic effects for centuries. A 2010 trial found a THC and CBD extract eased cancer pain more than placebo, but two later phase 3 trials of the same spray did not.
Anxiety and Sleep
Anxiety and sleeplessness often accompany cancer. One study looked at the potential for CBD to be beneficial in promoting sleep and reducing anxiety. That 2019 case series was of 72 adults at a psychiatric clinic, not cancer patients; anxiety scores fell in most, while sleep gains were less steady.
CBD is not approved for any cancer use, and it can change how other medicines work, so tell your oncology team before taking it. CBD also has side effects of its own, listed below.
Side-Effects of CBD
CBD is not harmless, and its effects reach beyond the brain. The FDA lists these possible harms and side effects of CBD, among others:
- Liver injury
- Interactions with other medicines
- Drowsiness, especially with alcohol or sedatives
- Diarrhea and decreased appetite
- Changes in mood, such as irritability and agitation
Dosage
If you and your physician decide to try CBD for symptoms during cancer care, do not choose on price alone; Florida requires hemp extract sold in the state to have an independent lab certificate of analysis. Buy from a seller that links each batch to its lab certificate. Check that the product label matches its lab certificate, since CBD products vary in content. There is no FDA-established CBD dose for cancer symptoms, so ask your oncologist or a qualified physician before choosing an amount.
Keep in mind that CBD taken by mouth, as an oil, capsule or edible, acts slowly: for prescription CBD, blood levels peak 2.5 to 5 hours after a dose. Daily use still carries the FDA’s warnings on liver injury and drug interactions.
Vaping CBD is not studied for cancer flare-ups, and CDC warns that inhaled cannabis products can harm the lungs.
The Takeaway
The medical benefits of the cannabinoid CBD need more scientific research. The National Cancer Institute says cannabinoids may help with cancer-related side effects such as nausea and appetite loss. In the course of cancer treatment, be sure that you discuss all treatment possibilities, even treatment with cannabis, with your health care professional.
