Dr. Amanda Hu — Disclosures: Advisory board member for Pentax Medical – for launching a stroboscopy system in Canada. Received funding from 1. American Academy of Otolaryngology-Head and Neck Surgery Women in Otolaryngology Endowment Grant, 2. BC Otolaryngology Society Research Grant, and 3. Michael Smith Foundation Reach Grant. Received honoraria: Consultant for Merck Inc – for the creation of a chronic cough educational PowerPoint presentation. Mitigating Potential Bias: Treatments or recommendations in this article are unrelated to products/services/treatments involved in disclosure statements.
What I did before
Cannabis was legalized in Canada in 2018. This has led to substantial growth in the cannabis industry. Statistics Canada reported that approximately 4.6 million or 12.5% of persons ≥ 15 years old participated in consuming cannabis in the past 3 months.1 Nearly half of all Americans have smoked cannabis at least once and cannabis is the second most commonly consumed drug in the US, after alcohol.2
Until recently, we did not understand well whether cannabis smoking was directly linked with otolaryngology-related symptoms or head and neck (H&N) cancers. Due to this uncertain clinical relevance, we did not routinely ask our patients about cannabis use. In retrospect, in order to maintain good doctor-patient rapport prior to the legalization of cannabis, we may have also been hesitant to explore our patients’ cannabis use.
What changed my practice
While we still do not know the full extent of how cannabis may effect otolaryngology-related symptoms or diagnoses, recent evidence has emerged that shows cannabis smoking is related to significant patient morbidity.3 Namely, cannabis smoke exposure increased the risk of oropharyngeal cancer in a dose-dependent manner.4,5 Cannabis use may also be associated with hearing loss, vestibular dysfunction, and tinnitus.6.7 In these circumstances, smoke inhalation and molecular oxidization may cause damage to cochleovestibular hair cells leading to otolaryngology-related morbidity. As with cigarette smoking, cannabis smoking was also linked to an increased chance of getting sinusitis.6 Because recent peer-reviewed evidence has demonstrated the potential risk for detrimental health problems due to cannabis smoking, this suggests that care providers should be asking about both cannabis and tobacco smoking when dealing with patients with otolaryngological signs and/or symptoms.
Anecdotally, we saw a patient with head and neck cancer who had minimal nicotine smoking history, but who had a history of heavy cannabis smoking. Cigarette smoking is well known as one of the leading risk factors for head and neck cancer, but when the patient presented there was little research on the effect of cannabis smoking. Laryngoscopy showed substantial black debris in the airway with erythematous mucosa, both of which were likely associated with the patient’s cannabis smoking history and may have contributed to their cancer and voice symptoms.
What I do now
We now routinely ask all our patients about cannabis smoking, as we would with nicotine use. If appropriate, we then further characterize our patients’ cannabis use, including asking about the frequency, duration, and quantity of use. This allows us to document joint years similarly to how one would with cigarette smoking pack years. Recent research in tobacco smoking has found that duration of smoking may be more important than pack years in determining risk of developing smoking-related diseases, such as lung cancer; however, it is unknown if this concept also applies to cannabis consumption. Lastly, we now discuss risk reduction strategies with our patients.
The American Journal of Public Health has published evidence-based Lower-Risk Cannabis Use Guidelines (LRCUG).9,10 These guidelines were based on two systematic reviews on reducing adverse health outcomes in all specialties, including psychiatry, respirology, neurology, and obstetrics. 9,10 Some recommendations from these guidelines include vaporizing cannabis and using cannabis edibles. These routes of administration reduce exposure to carbon monoxide and pyrolytic toxins to lessen chronic respiratory symptoms while maintaining adequate pain management and other therapeutic doses.9,10 Decreased frequency and intensity of cannabis smoking can also mitigate some of the previously described negative health consequences. 9,10 Avoiding early age initiation of cannabis use is preferable, especially before the age of 16 years. 9,10 Driving while impaired from cannabis is associated with an increased risk of motor vehicle accidents, so it is recommended to refrain from driving or operating machinery at least 6 hours after using cannabis. 9,10 First responders and pilots may require a greater amount of time. Avoid mixing cannabis with other drugs, like alcohol, recreational drugs, and prescription drugs, especially opioids and sedatives. The most effective way, however, to avoid any risks of cannabis smoking is abstinence.10
- Cannabis in Canada: Get the facts — The Government of Canada (View) Accessed November 28, 2021.
- Cannabis Awareness and Prevention Toolkit — Stanford Medicine (View) Accessed November 28, 2021.
- Statistics Canada. Cannabis statistics. 2018. (View). Updated October 17, 2018. Accessed November 28, 2021.
- Ahrnsbrak R, Bose J, Hedden SL, Lipari RN, Park-Lee E. Key Substance Use and Mental Health Indicators in the United States: Results from the 2016 National Survey on Drug Use and Health. SAMHSA. 2017. (View).
- Phulka J, Howlett J, Hu A. Cannabis related side effects in otolaryngology: a scoping review. J Otolaryngol Head Neck Surg 2021 Sep 27;50(1):56. DOI:10.1186/s40463-021-00538-6. (View).
- Marks M, Chaturvedi A, Kelsey K, et al. Association of marijuana smoking with oropharyngeal and oral tongue cancers: Pooled analysis from the INHANCE consortium. Cancer Epidemiol Biomarkers Prev. 2014;23(1):160-171. DOI:10.1158/1055-9965.EPI-13-0181. (View).
- Xie M, Gupta M, Archibald S, Stanley B, Young J, Zhang H. Marijuana and head and neck cancer: an epidemiological review. J Otolaryngol Head Neck Surg. 2018;47(1):73. DOI:10.1186/s40463-018-0319-2. (View).
- Han B, Gfroerer J, Colliver J. Associations Between Duration of Illicit Drug Use and Health Conditions: Results from the 2005-2007 National Surveys on Drug Use and Health. Ann Epidemiol. 2010;20(4):289-297. DOI:10.1016/j.annepidem.2010.01.003. (View with CPSBC or UBC).
- Liedgren S, Odkvist L, Davis E. Effect of marijuana on hearing. J Otolaryngol. 1976;5(3):233-237. DOI: 10.1097/00043764-197611000-00028. (Request with CPSBC or view with UBC).
- Pleasants RA, Rivera P, Tilley SL, Bhatt SP. Both Duration and Pack-Years of Tobacco Smoking Should Be Used for Clinical Practice and Research. Ann Am Thorac Soc. 2020 Jul;17(7):804-806. DOI: 10.1513/AnnalsATS.202002-133VP. (View).
- Chaiton M, Kundu A, Rueda S, Di Ciano P. Are vaporizers a lower-risk alternative to smoking cannabis? Can J Public Health. 2021 [Epub ahead of print]. DOI: 10.17269/s41997-021-00565-w. (View with CPSBC or UBC).
- Fischer B, Russell C, Sabioni P, van den Brink W, Le Foll B, Hall W, Rehm J, Room R. Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations. Am J Public Health. 2017 Aug;107(8):e1-e12. DOI: 10.2105/AJPH.2017.303818. (View).
Additional Free Education:
Out of the Weeds: bridging the knowledge gap about the health risks of inhaling cannabis in the airways
April 4 (Mon) | 1830–2000 PST | FREE Webinar
Target audience: Physicians and other health care providers.
Up to 1.5 Mainpro+/MOC Section 1 study credits
Agenda: Cannabis was legalized in Canada with the introduction of the Cannabis Act in 2018. This rapid legalization has led to a knowledge gap in physicians. Although most users inhale cannabis, few physicians know the health effects of inhaling cannabis in the airway. A multidisciplinary panel of highly experienced and knowledgeable medical experts will answer your questions, share their experiences, and recommend best practices in help physicians guide their patients to make informed choices on cannabis usage.
- Define foundational and evidence-based considerations for cannabis use including legal status and administration routes
- Describe the airway benefits and harms of cannabis use, highlighting different impacts related to route of administration e.g. Vaping
- Critique recent research findings on cannabis-related side effects and pathologies in the airway
- Outline approaches to support patients in making informed, evidence-based choices on cannabis use including harm reduction strategies
- Dr. M-J Milloy, Professor of Cannabis Science at UBC and Research Scientist at BC Centre on Substance Use
- Dr. Amanda Hu, Clinical Associate Professor with the Division of Otolaryngology – Head & Neck Surgery at UBC
- Dr. Joel Howlett and Dr. Ameen Amanian, Resident Physicians with the Division of Otolaryngology – Head & Neck Surgery at UBC
- Dr. Wan Tan, Honorary Professor with the Division of Respirology at UBC
- Dr. James McCormack, Pharmacist and Professor with the Faculty of Pharmaceutical Sciences at UBC
- Dinusha Peiris, RSLP, Speech language pathologist at the BC Cancer Agency
- Moderator: Dr. Christie A Newton, Director of Continuing Professional Development, Associate Professor with the Department of Family Practice at UBC