Unpacking the Role of Cannabis in Oncology as Reclassification of the Drug Pends


Brooke Worster, MD, MS, FACP, and chief medical officer at EO Care, details what oncologists should know about medical cannabis pending the expectant marijuana reclassification from a Schedule I to a Schedule III drug.

Brooke Worster, MD, MS, FACP

Brooke Worster, MD, MS, FACP

With conversations swirling around medical cannabis and the expectant marijuana reclassification from a Schedule I to a Schedule III drug, oncologists are looking for guidelines as cannabis can serve a critical role in improving quality of life (QOL) for patients with cancer, according to Brooke Worster, MD, MS, FACP.

“We need a way for patients to have equitable access to both cannabis and good guidance because otherwise, we’re creating another health care inequality which happens all the time. Right now, the way that patients are getting guidance is from wholly nonmedical sources by and large,” Worster said in an interview with OncLive®. “The call to action should be for us as a medical community, societies like ASCO, and the government—[who] can engage in this and fund it—to say we need to get behind ways that we can provide equitable medically-based guidance to patients so that they can use [cannabis] and not be at risk.”

The Centers for Disease Control and Prevention have reported that certain cannabinoids may aid in the treatment of chemotherapy-induced nausea and vomiting as well as neuropathic pain. Dronabinol (Marinol and Syndros) and nabilone (Cesamet) are synthetic forms of cannabinoids that are FDA-approved for use in patients with chemotherapy-associated nausea and vomiting.1

On January 29, 2024, 12 senators including Senate Majority Leader Chuck Schumer sent a letter to the Drug Enforcement Administration (DEA) urging them to reschedule cannabis.2 This comes following the August 29, 2023, US Department of Health and Human Services recommendation, which was made public in January, issued to the FDA that cannabis be reclassified from Schedule I to Schedule III under the Controlled Substances Act.3

Worster noted that approximately 40% to 50% of patients with cancer use cannabis, and in the interview, she detailed what oncologists should know about recommending cannabis and what group of patients would be ideal to receive the complimentary agent. Worster is an associate professor of medicine, division director of Supportive Oncology, chief medical officer at EO Care, and director of the Cannabis Medicine, Science and Business Master’s Program, Institute of Emerging Health Professions, all at Jefferson Health in Philadelphia, Pennsylvania.

OncLive: As the DEA is expected to announce the reclassification of cannabis from a Schedule I drug to a Schedule III drug, what does this mean and how will this affect supportive care in oncology?

Worster: [The decision] will have impacts much broader than supportive oncology—the number one immediate change is in the stigma associated with cannabis. For so long it has been an illegal substance and the ramifications in terms of policing, arrests, and recrimination have been associated with it. If it gets rescheduled and records get expunged, that’s incredibly important in terms of equitable access and comfort with discussion; that crosses all boundaries of medicine.

The other thing with the prevalence of use in the oncology space is that the [rescheduling would] drop barriers very quickly to research and funding surrounding cannabis. Those are the two immediate changes; the rest has to funnel through states’ perspectives and all kinds of other things.

How have you seen cannabis affect QOL for patients with cancer?

I have seen it across the board. The 2 most prevalent symptoms that people have a night and day response [with cannabis to]—and it’s often because they’ve been struggling and this is thought of too late—are chemotherapy-induced nausea and vomiting. When patients are on 5 or 6 other drugs and they’ve been hospitalized after every regimen for their breast cancer treatment or something along those lines, this is a game changer a lot of times.

Patients who are struggling with pain [also experience benefit with cannabis] and in today’s world with cautiousness and fearfulness around opioids, there is a want for other options. There’s also sometimes a lack of access to both opioids and cannabis and when people get guidance and a product that is appropriate for them, the cancer-related pain and chemotherapy-induced nausea and vomiting [improve]; I’ve had patients come back to me 2 weeks later and say, ‘I haven’t felt this good in months.’

What should medical oncologists who aren’t as experienced with cannabis know about medical cannabis?

The first thing that they should know is that their patients are using it; 40% to 50% of patients say they’ve tried cannabis since their cancer diagnosis and that means we should be talking about it, at least asking, or bringing it up. Oncologists don’t have to be experts in it by any means, but we can’t hide our heads in the sand about this. In terms of a benefit, we should think about it earlier on in the regimen for our patients suffering from pain, nausea, and appetite concerns. If patients are struggling with insomnia related to anxiety or pain that is another good opportunity.

The other thing [to consider] on the cautious side is if your patients are getting immunotherapy. We don’t know yet, but if they’re taking very high doses of cannabis—high mgs of CBD or THC—it might have an impact on the patient’s immune system. It’s another reason for physicians to be asking and engaging [with patients] because even if patients are experiencing benefits, they don’t need to be taking it in super high doses. Often what budtenders or others are telling patients is beyond the spectrum of what might be beneficial for them and what might have an impact on their immunotherapy.

What should be known about the safety of medical cannabis?

Please try to push your patients away from smoking. I know that sounds silly in this day and age, [but] there’s nothing that doctors want patients to be lighting on fire and inhaling into their lungs. Without guidance, that’s what patients are getting; they’re getting the flower and someone’s rolling it into a joint or [something similar]. They’re inhaling it and smoking it, and we know that the rapid onset especially of the higher dose THC products into your bloodstream can trigger cardiovascular events. There’s a dose-response relationship between increased heart rate and THC, and there are safer forms [to use cannabis in]. From a risk reduction perspective, talk to your patients about it and get them not to smoke—cannabis falls in that group.

Which patients should you be cautious of giving medical cannabis to?

Some of [the consideration has to do with the fact] that patients have to feel comfortable wanting to use cannabis. Patients with cancer probably have a symptom that may be responsive to [cannabis], so that encompasses a huge bucket of people. Who are the ones that you should say, ‘I don’t think this is for you?’ For patients with uncontrolled mental illness and even significant depression—we have no data that cannabis is helpful for depression, and [it] can make it worse. Those are the people that I don’t think this is right for.

Patients who have lung or head and neck cancer can certainly have cannabis, but you should make sure they’re not smoking it. Patients who are going for bone marrow transplants absolutely should not be smoking it [either]. Patients who are struggling with nausea and vomiting, pain, insomnia, and appetite issues should have it. That’s a lot of your patients with cancer and this is an opportunity to use and decrease some of the other pharmaceutical products that we worry more about drug-drug interactions with [for patients].

How does medical cannabis compare with other supportive therapies for patients with cancer?

That’s a hard question to answer because supportive therapies [range from] acupuncture to opioids. Cannabis is undeniably safer than the opioids and benzodiazepines that I prescribe and yet I still prescribe them because there’s a role for them for patients with cancer. [Cannabis’s] safety profile is a valuable part of it as a therapeutic [because] it doesn’t have a ton of drug-drug interactions, affect respiratory rate, [or] cause as significant of concern about withdrawal or addiction as some of the other drugs that we use [do]. In that way, if I have a patient that’s higher risk or there is more concern for some of that, I think about cannabis much sooner than I think about some of the other drugs that can be more addicting.

[However], cannabis certainly has drawbacks that are more significant than acupuncture. It’s tough to rank them, but there are a lot of reasons that I do think about it in some populations more than any of the drugs that I can prescribe at a pharmacy. There are times that I tell people, ‘This isn’t good, and I don’t think you should use it,’ and they’re using it and not telling anyone because they’re scared about it.

How do you anticipate medical cannabis affecting supportive/integrative therapies for patients with cancer in the future?

ASCO already came out with [guidelines] talking about how important it is for us to engage in this conversation with our patients with cancer; there’s increasing data around its effectiveness in certain areas, and we need to be aware of the risks so [we can advise those] patients who need to steer away from it. The guidelines that come out first and the most critical ones say what we need is guidance. We’re not going to know the exact mg strength for every person, but we need to engage in this conversation and have a better way to help people avoid risks.

As director of Supportive Oncology at Jefferson Health, are there any other supportive therapies that you’d like to highlight?

I see patients with cancer all the time who are struggling with symptoms [regarding] the impacts of cancer on their sex life, mental health, sleep, and relationships. Every opportunity that you have to engage in the conversation about what is most impacting someone’s QOL, is the therapeutic that I want to highlight—that dialog to say what is bothering you the most. [I say], ‘If this is affecting your ability to have sex with your partner, then let’s talk about what we can do to help you.’

There are so many options out there that it’s impossible to name one therapy that I want to highlight; I want to highlight that patients are struggling with these symptoms, and they feel like they’re not supposed to acknowledge it. We have so many tools at our fingertips when we think outside the box of writing a prescription and going to a CVS to get it that can help patients. Opening that box to dive in and talk about the unsaid things [is crucial].

Is there any ongoing research you’re involved in with medical cannabis or supportive therapies that you’d like to highlight?

Our 2 NCI-funded studies are looking at the impacts of cannabis use and outcomes comparing patients who are using cannabis [vs] those who aren’t in specific disease sites. We’re looking at both effects on their patient-reported outcomes and QOL. Then we’re looking at immune markers in a subset of patients—we’re drawing blood from patients and asking if we are seeing a differential impact on immune markers that we track normally when patients are getting immunotherapy.

Then we’re following patients for 18 months and looking at whether there is any impact on disease progression. That’s one of the big questions we want to answer and thankfully the NCI recognized this as important. We’re going to look at 450 patients with solid tumors who are new to immunotherapy and are using cannabis [compared with] those who aren’t [to ask] whether there a difference that could be attributable to [cannabis].


  1. Centers for Disease Control and Prevention. Marijuana and public health. Cancer. Accessed March 26, 2024. https://www.cdc.gov/marijuana/health-effects/cancer.html
  2. Letter to the DEA on descheduling marijuana. Accessed March 26, 2024. https://www.documentcloud.org/documents/24390831-20240129-letter-to-dea-on-descheduling-marijuana-1
  3. Kessler CD, Bleifer CB, Babin R, Daly T. Cannabis in 2024: HHS rescheduling recommendation and SAFER banking. Akin. February 23, 2024. Accessed March 26, 2024. https://www.akingump.com/en/insights/alerts/cannabis-in-2024-hhs-rescheduling-recommendation-and-safer-banking#:~:text=Overview,Controlled%20Substances%20Act%20(CSA)
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