Cancer and cannabis: What patients need to know

September 9, 2020 Cancer, Dan L Duncan Comprehensive Cancer Center, Healthcare, Molly Chiu

Cancer treatment can come with a number of side effects like pain, loss of appetite, nausea, mood disruptions and loss of sleep. Oncologists use a wide variety of FDA-approved drugs to treat these effects, but some patients may choose to use cannabis products to help alleviate their pain.

Dr. Charu Agrawal, a palliative care specialist at the Dan L Duncan Comprehensive Cancer Center at Baylor St. Luke’s Medical Center, shares suggestions for cancer patients who may be interested in cannabis.

“Physicians don’t usually advocate for the use of cannabis products, but if you ask patients, it’s astonishing the number of people who are already on them or are contemplating using them,” Agrawal said. “Most patients say they heard about it from friends or family.”

Medical cannabis products include cannabidiol (CBD) and tetrahydrocannabinol (THC) and can be taken orally or inhaled. While CBD is used as an anti-inflammatory, THC use leads to euphoria or sedation. Agrawal advises that anyone considering using cannabis speak with his or her oncologist first.

Oncologists will look for any possible side effects of the drug or how it might interact with cancer treatment. CBD can inhibit the receptor that metabolizes many common drugs, like methadone, statins, antidepressants and opioids, leading to higher levels of those drugs in the blood stream.

“I tell my patients, you need to let us know if you’re on THC or CBD, just like any over-the-counter drugs or herbal supplements,” Agrawal said. “Be open and honest about what you’re doing and how much.”

Few studies have been done to understand how cannabis impacts the side effects of cancer treatment. Current research has only show cannabis to be effective in chemotherapy-induced nausea and vomiting. So far, THC has only been FDA approved for that purpose. Other prescription medications have been shown to be more effective and more tolerated in treating symptoms like pain, loss of appetite and mood changes.

Still, many cancer patients say that cannabis products help them with sleep and appetite. Agrawal said that might be due to the placebo effect.

“For patients with terminal cancer who only have weeks or months to live, I say it’s fine to try anything that makes you feel better,” she said. “But for people with curative illness, I would be a lot more reluctant to have them try it. We need to practice evidence-based medicine. Let’s not risk anything interacting with treatment and you being cured.”

Agrawal said she hopes to see more regulation of cannabis across the U.S. in order to facilitate multi-center clinical trials that can evaluate the effectiveness of THC and CBD in a large, diverse patient population. Regulation can also help lead to higher quality THC and CBD options. Agrawal recommends that patients who want to use cannabis products go to a state with an established medical marijuana program to ensure the products are safe.

“Make sure you’re getting the drug from a trusted source and you know what you’re putting into your body,” Agrawal said. “Don’t go to your local mom and pop CBD shop.”

Agrawal believes the topic has become less taboo and she encourages patients to bring it up.

“We have to take away the stigma,” Agrawal said. “I will let my patients know what the evidence shows. But if a patient feels it’s helping them, I’m not going to tell them to stop taking it unless it interferes with treatment.”

Dr. Agrawal is an assistant professor of medicine – hematology and oncology at Baylor College of Medicine.