According to the National Cancer Institute, there have been no clinical trials of cannabis as a treatment for cancer in humans -- a search on the Complementary & Alternative Medicine PubMed database (maintained by the National Institutes of Health) yields no results. However, cannabis and cannabinoids have been studied in clinical trials for ways to manage side effects of cancer and cancer therapies, including the following:
Cannabidiol (CBD) by mouth to treat solid tumors that have recurred (come back).
An oral spray combining 2 cannabinoids (delta-9-THC and CBD) given with temozolomide to treat recurrent glioblastoma multiforme.
Cannabidiol (CBD) to treat acute graft-versus-host disease in patients who have undergone allogeneic hematopoietic stem cell transplantation.
Delta-9-THC taken by mouth: Two cannabinoid drugs approved in the United States are available under the names dronabinol and nabilone. Both dronabinol and nabilone are approved by the Food and Drug Administration (FDA) for the treatment of chemotherapy-related nausea and vomiting in patients who have not responded to standard therapy. Many clinical trials have shown that both dronabinol and nabilone worked as well as or better than some of the weaker FDA-approved drugs to relieve nausea and vomiting. Newer drugs given for chemotherapy-related nausea have not been directly compared with Cannabis or cannabinoids in cancer patients.
Inhaled Cannabis: Ten small trials have studied inhaled Cannabis for the treatment of chemotherapy-related nausea and vomiting. Various study methods and chemotherapy agents were used with mixed results. There is not enough information to interpret these findings.
Oral spray with delta-9-THC and cannabidiol (CBD): Nabiximols, a Cannabis extract given as a mouth spray, was shown in a small randomized, placebo-controlled, double-blinded clinical trial in Spain to treat chemotherapy-related nausea and vomiting.
There is growing interest in treating children for symptoms such as nausea with Cannabis and cannabinoids, although studies are limited. The American Academy of Pediatrics has not endorsed Cannabis and cannabinoid use because of concerns about brain development.
Delta-9-THC taken by mouth: A clinical trial compared delta-9-THC (dronabinol) and a standard drug (megestrol) in patients with advanced cancer and loss of appetite. Results showed that delta-9-THC was not as effective in increasing appetite or weight gain in advanced cancer patients compared with standard therapy. However, a clinical trial of patients with HIV /AIDS and weight loss found that those who took delta-9-THC had increased appetite and stopped losing weight compared with patients who took a placebo.
Inhaled Cannabis: There are no published studies of the effect of inhaled Cannabis on cancer patients with loss of appetite. Studies of healthy people who inhaled Cannabis showed that they consumed more calories, especially high-fat and sweet snacks.
Combining cannabinoids with opioids: In a small study of 21 patients with chronic pain, combining vaporized Cannabis with morphine relieved pain better than morphine alone, while combining vaporized Cannabis with oxycodone did not produce significantly greater pain relief. These findings should be tested in further studies.
Delta-9-THC taken by mouth: Two small clinical trials of oral delta-9-THC showed that it relieved cancer pain. In the first study, patients had good pain relief as well as relief of nausea and vomiting and better appetite. A second study showed that delta-9-THC could be given in doses that gave pain relief comparable to codeine. An observational study of nabilone also showed that it relieved cancer pain along with nausea, anxiety, and distress when compared with no treatment. Neither dronabinol nor nabilone is approved by the FDA for pain management.
Cannabis plant extract medicine: A study of an extract of Cannabis that contained specific amounts of cannabinoids, which was sprayed under the tongue, found it was effective in patients with advanced cancer whose pain was not relieved by strong opioids alone. Patients who received the lower doses of cannabinoid spray showed markedly better pain control and less sleep loss compared with patients who received a placebo. Results showed that, for some patients, control of their cancer-related pain continued without needing higher doses of spray or higher doses of their other pain medicines.
Inhaled Cannabis: A small case series found that patients who inhaled Cannabis had improved mood, improved sense of well-being, and less anxiety.
Source: National Cancer Institute