Don't Ask,Don't Tell: Cannabis Use in Adolescent and Young Adult Cancer Patients

Introduction

States are increasingly legalizing cannabis for both recreational and medical use, but little research exists on medical cannabis use among adolescent and young adult (AYA) cancer patients. Cannabis may be readily accepted in this population as well as provide relief from cancer- and chemotherapy-related symptoms, but it raises issues of potential abuse and adverse effects. Oncologists should ask their AYA patients about cannabis use but may be reluctant to do so, and AYA patients may not disclose their use, inadvertently creating a “don't ask, don't tell” environment that may compromise patient care. This article addressed trends in cannabis use in this population, risks and benefits of use, and the importance of patient–provider communication surrounding its use.

Cannabis in the United States

California legalized cannabis for medical use in 1996; today 33 states and the District of Columbia have created medical cannabis programs, and the national trend toward legalization continues. ¹ At the time of the 2014–2015 National Survey on Drug Use and Health, when even fewer states had medical cannabis programs, 12.9% of U.S. adults had used cannabis in the previous year, and 9.8% of these previous-year cannabis users reported use for medical reasons.^2,3 Almost 80% of these medical cannabis users lived in states with legal medical cannabis programs. Similarly, residents of states where medical cannabis is legal have higher rates of cannabis use—however, they also have higher rates of abuse and dependence, and number of years since legalization may correlate directly with rates of cannabis use.^4,5

Cannabis in AYA Patients

With the increasing pervasiveness of cannabis use in the United States has come increased research on AYA cannabis use in cancer patients and survivors, but much remains unknown. ⁶ In the 2017 Youth Risk Behavior Surveillance System survey, 19.8% of high school students reported current cannabis use. ⁷ A recent retrospective study of cancer patients ages 18–39 seeking symptom management found that 30% tested positive for tetrahydrocannabinol on urine drug testing; similarly, another study of 100 AYAs with primarily hematological cancers found that 33% used cannabis in the previous year.^6,8 Although these data may not reflect cannabis use among AYA as a whole, they suggest that young adults with cancer may use cannabis more frequently than those in the general population.

Surveys of adults have also revealed that many use cannabis in conjunction with or as part of their cancer care, and most have experienced some benefit.^3,9 These data are particularly important in AYA, who may have longer life expectancies than older adults with cancer and who may be at increased risk of other cannabis-related health problems such as mental illness, impaired brain development, and infertility. ¹⁰ However, ineffective patient–provider communication may hinder both understanding of AYA attitudes toward medical cannabis and its appropriate incorporation into cancer treatment.

Disclosure and Communication

Although most research on cannabis use in cancer patients focuses on older adults, it nonetheless provides valuable insight into the patient–oncologist relationship with regard to disclosure of cannabis use. In a survey of 1987 cancer patients in Canada, only 5% of respondents said they would not feel comfortable telling their oncologist about their prior or current cannabis use. ¹¹ However, among the 193 respondents who had never used cannabis but had contemplated using it as part of their cancer treatment, 8% said they would feel comfortable discussing cannabis with their oncologists and only if their oncologists brought it up. A survey of patients at a comprehensive cancer center in California found that 62% of active cannabis users told their cancer teams about their cannabis use. ³

As cannabis has the potential to be both beneficial and harmful, ideally 100% of patients should tell providers about their cannabis use, but as the Canadian study demonstrates, patients may need to be prompted to do so. Research on specifically AYA patient–provider communication about cannabis is limited, but many younger patients have difficulty communicating with older clinicians; AYA with cancer face additional barriers to effective communication, such as withdrawal when confronted with a new cancer diagnosis and parents hoping to be involved more closely in care. ¹² Presence of parents during discussions of cancer diagnosis and treatment may also hinder AYA disclosure of cannabis use.

It is also quite likely oncologists are failing to ask their AYA patients about cannabis use, as well as failing to provide information about it. In the California survey, most respondents stated that they wanted to learn more about cannabis and cancer, and 74% preferred getting information from their cancer team; however, <15% received information from their cancer physician or nurse. ³ They thus resorted to information from friends and family, news articles, websites, other cancer patients, and the like, and >30% received no information at all.

Interestingly, when asked to rate their interest in education about cannabis use during cancer therapy, significantly fewer individuals in the <30 age group reported low interest, and significantly fewer individuals in the ≥70 age group reported high interest. This suggests that the lack of patient–provider communication about cannabis may be disproportionately detrimental to AYA patients, as they are hoping for information they are not receiving.

These communication failures are not without consequence. On one hand, AYA cancer patients may miss out on purported—although not well established—benefits of cannabis use in oncology, such as improvements in appetite, nausea, and pain. ³ On the other hand, limited conversations with providers may cause patients to seek cannabis without medical guidance, which can be dangerous.

First, there is the risk of dependence. This is particularly important in AYA patients, as they may have longer life expectancies than older patients and thus risk decades of struggling with substance use; in addition, earlier age of first cannabis use is associated with a greater likelihood of dependence.^13,14 Second, chronic cannabis use can result in a plethora of potential negative health outcomes, including some particularly relevant to AYA with cancer. For example, both cannabis and certain chemotherapeutic agents may be associated with infertility problems; in addition, regular use of cannabis in adolescence is associated with worsening IQ and school performance.^10,14–16

Finally, although the potential drug–drug interactions involving cannabis and chemotherapeutic agents are not well established, cannabis has been found to modulate cytochrome P450 isozyme 3A (CYP3A), which is involved in the metabolism of many chemotherapeutic agents; thus, cannabis may affect the safety and efficacy of chemotherapeutic regimens, highlighting the importance of patient–physician communication regarding cannabis use.^17,18 The California patient survey found that, of respondents who had previously used cannabis and quit, 10 of 51 quit based on recommendation from their cancer or primary care physician. ³ Cannabis use in cancer care may not be beneficial, can even be harmful, and should be monitored by a clinician.

Although many things can limit patient–provider communication—time limitations, cultural factors, to name a few—one crucial barrier in AYA cancer patients with regard to cannabis is physician education.^19–22 Much remains to be understood about the efficacy and dangers of cannabis use in cancer care, and the evidence in younger patients is lacking. ²³

Studies of pediatric oncology providers reveal that most are willing to help youth with cancer access medical cannabis; however, many are wary to do so due to lack of standards, and others lack knowledge of how it can be used, and their specific state regulations.^20,21 Similarly, a cross-sectional survey of Australian health professionals found that 74% felt that they were insufficiently informed about access to cannabis, 59% about evidence base, and 65% about potential drug interactions, and 46% were unsure whether they would recommend cannabis to their cancer patients, further indicating lack of confidence on the topic. ²²

Conclusion

As cannabis use—both recreational and medical—becomes legal in more states and as potential health benefits continue to be discovered, it is important for physicians to be abreast of new research, regulations, and recommendations. This may require additional education on cannabis use in medical school, as well as training in residency programs and among practicing physicians. In addition, given the health concerns particularly relevant to AYA cancer patients, such as the potential for addiction and interactions with chemotherapeutic agents, it is crucial for physicians to ask their patients about cannabis use. Furthermore, providers should do this in a nonjudgmental manner; this will create a conducive environment for patients to share personal information, and also encourage disclosure in the future.

Providers would likely be most effective in conveying their concerns about cannabis nonjudgmentally by employing the ask-tell-ask technique, which involves asking the patient about his or her understanding, communicating the relevant information to the patient, and asking the patient what he or she understood. ²⁴ This helps make patients feel heard, which may be of chief importance in adolescents and young adults who are in the process of developing their identities and becoming self-sufficient. ²⁵ It also strengthens the physician–patient relationship and prevents one-way communication, which could result in lack of disclosure. Although much remains to be understood about medical cannabis, one thing is for certain—physicians must reform their “don't ask, don't tell” approach.