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IBS11 - Electronic Cigarettes and Heat-Not-Burn Tobacco Products - How Are They Different (Ticketed Session) (ID 42)
- Event: WCLC 2019
- Type: Interactive Breakfast Session
- Track: Prevention and Tobacco Control
- Presentations: 1
- Now Available
- Coordinates: 9/09/2019, 07:00 - 08:00, Amsterdam (2011)
IBS11.03 - Cannabis and Lung Cancer (Now Available) (ID 3349)
07:00 - 08:00 | Presenting Author(s): James Jett
Cannabis is a generic term that includes cannabinoids, marijuana (MJ) and hemp derived from the plant Cannabis sativa. Documented use dates back several centuries BC. In 1970 the Controlled Substance Act classified cannabis as a Schedule I drug with high abuse potential and no medical use. Other Class I drugs are heroin, LSD and cocaine. Similarly, cannabis is illegal in many other countries. There are many different cannabinoids in cannabis but the two main ones are delta-9-tetrahydrocabinol (THC) and cannabidiol (CBD). The THC is associated with psychoactive effects of euphoria and relaxation and CBD is not associated with the euphoric effects but is associated with anxiolysis. Pharmaceutical grade cannabinoids are scheduled/classified differently and there are several FDA approved medicines in the USA and available is many other countries. Dronabinol (THC) and nabilone are available for chemotherapy induced nausea and vomiting (CINV). Nabiximol (1:1 mixture of THC and CBD) is used for analgesic effects and spacicity due to multiple sclerosis. It is approved for use in many countries but not the USA. (NASEM; Jett et al)
Cannabis products can be smoked, vaporized, ingested or applied topically. Smoked or vaporized cannabis reaches the brain within 30 seconds to a few minutes and the effects subside over 1-3.5 hours which makes it easier to titrate the dose/effects than ingested products which results in effects 30 minutes to 2 hours after ingestion and may last 5-8 hours. The average THC levels in MJ were 4% in 1995 and increased to 12% in 2012. However, in recent years with new products such as wax, honey oil, dabs etc that may have concentrations of THC of 40-80% so the effects on the user may be more psychologically and physically intense and effects may include paranoia, anxiety, panic attacks and hallucination.
Cannabis containing many of the same toxins and carcinogens as tobacco smoke. Regular smoking of MJ is associated with airway inflammation similar to cigarette smoking and regular use of cannabis alone (without tobacco) may result in symptoms of chronic bronchitis. (Douglas IS et al) There is no conclusive evidence that cannabis smoking is associated with an increased incidence of lung cancer. The best available evidence comes from six case-control studies within the International Lung Cancer Consortium (Zhang LR et al, NASEM). An epidemiologic review of six lung cancer studies concluded that these studies did not support an association of MJ use and lung cancer (Huang Y-HJ et al). A limitation of these pooled studies is the small number of heavy and chronic users of cannabis. The National Academy of Science, Engineering and Medicine (NASEM) expert panel concluded that there is moderate evidence of no statistical association between cannabis smoking and the incidence of lung cancer.
There is an increasing body of evidence that cannabinoids have some anti-cancer effects in cell cultures and animal studies. However, there are no convincing clinical trials demonstrating that cannabis is effective in cancer patients.(NASEM) There is insufficient evidence to support the use of cannabinoids in cancer patients, in spite of claims on the web/internet that concentrated cannabis oils can cure cancer.
There is evidence that use of cannabinoids are of benefit for treating chronic pain, including neuropathy. Whiting et al performed a meta-analysis of 28 studies that mainly used pharmaceutical grade (Schedule III) cannabinoid based drugs such as nabiximol or nabilone and some smoked or inhaled THC trials. All but one was placebo controlled. The odds ratio was 1.4 of reporting 30% or more improvement in pain with cannabinoids. The NASEM concluded that there is substantial evidence that cannabis is an effective treatment for chronic pain. There have been patient reported outcomes that suggest that cannabis is beneficial for pain, anxiety and depression and may reduce the use of prescription drugs. ( Corroon JM et al; Zaki P et al; Anderson SP et al).
The NASEM panel concluded stated that there is conclusive evidence that oral cannabinoids are effective antiemetics for treatment of chemotherapy induced nausea and vomiting (CINV). Nabilone and dronabinol are FDA approved drugs for CINV. Good quality studies of inhaled or ingested plant based cannabis for CINV are limited. Most of these randomized trials for CINV were before the use of 5-hydroxytryptamine (5HT3) receptor antagonists. Accordingly, many oncologists would use a 5HT3 antagonist initially. Nabilone or dronabinol may be used for rescue or refractory nausea and vomiting as backup treatment options. Patient reported outcomes have noted benefit from medical marijuana products for nausea and vomiting (Anderson SP et al).
The FDA has approved use of dronabinol for human HIV induced anorexia but there is currently insufficient evidence to support or refute the effectiveness of cannabinoids for cancer associated anorexia-cachexia (NASEM). However, cannabis has been reported to increase appetite and patient reported outcomes have again suggested benefit from medical marijuana.
In summary, there is no current evidence that smoking MJ results in an increased incidence of lung cancer. However, the landscape is changing rapidly with the legalization of medical and recreational cannabis. This along with the increasing concentration and dose of the available products may result in an increased number of heavy and chronic users. This will require careful follow-up. Other areas of urgent need, as related to this review, for controlled clinical trials include: 1) Do cannabinoids have any role in treatment of cancer? 2) Do cannabinoids have any efficacy in reduction of opioid use or dose? 3) Is there any role for cannabinoids in treatment of cancer anorexia-cachexia.
NASEM: National Academies of Sciences, Engineering and Medicine
Jett JR et al; J Thorac Oncol 2017; 13:480-487
Douglas IS et al; Ann Am Thorac Soc 2015; 12:1700-1710
Zhang LR et al; Int J Cancer 2015; 136:894-903
Huang Y-HJ et al; Cancer Epidemiol Biomark Prev 2015; 24:15-31
Whiting PF et al; JAMA 2015; 313:2456-2473
Corroon JM et al; J Pain Res 2017; 10:989-998
Zaki P et al; J Pain Manage 2017; 10:353-362
Anderson SP et al; J Oncol Prac pub online March 12, 2019
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