Cannabis Downside: For Patients Like Singer Melissa Etheridge, 63, The Newly Revealed Potential Negative Effects on Lifesaving Cancer Drugs

To decipher potential medication interactions, researchers obtained information from Lexicomp and Natural Medicines Comprehensive Database.

City of Hope’s Dr. Richard Lee, MD, Cherng Family Director’s Chair, Center for Integrative Oncology, who was involved in the study, told Oncology Nursing News, “Medical cannabis use is becoming more prevalent, and there is a risk for potential drug-drug interactions, including with medical cannabis.

“And so, we want to make sure that those patients, as well as healthcare providers out there, are aware of these potential risks for medication interactions.”

Medical cannabis use is growing in popularity, but may come with drug-drug interactions for patients with #cancer. An expert from @cityofhope discusses his research from #SIO2024 on the topic. https://t.co/I1u9HQdFUQ pic.twitter.com/PptrK2QbIL

— Oncology Nursing News (@OncNursingNews) November 11, 2024

The findings reportedly revealed that the risk for potential cannabis to drug interactions were “acetaminophen (9.5%, moderate severity), dexamethasone (8%, moderate severity), and ondansetron (6.3%, moderate severity).” And the “most common PMIs related specifically to chemotherapy treatment were with paclitaxel (4%, major severity) and doxorubicin (2%, major severity),” as per Oncology Nursing News.

Dr. Lee explained to the news outlet, “To really assess and identify these risks, first, clinicians need to be asking patients what they’re using, including over-the-counter [drugs], including cannabis, now that there are many different forms available over-the-counter and different states also allow medical cannabis use.

“So I think really the first step is understanding everything that a patient is using, not just prescription, but also nonprescription and over-the-counter types of medicines, including those that might be inhaled or ingested, even with liquids, gummies, and other forms.”

He continued, “Then it’s important to think about using these medication interaction software. So you might want to use something Lexicomp, or in this case, we also use one that’s very specific for herbs and supplements, called Natural Medicines interaction software, and this helped us identify many of the potential medication interactions with ongoing other medications that are using for as part of their treatment plan.”

Melissa Etheridge’s Cancer Journey & Medical Marijuana Use

Melissa Etheridge’s diagnosis came after she discovered a lump in her left breast. A biopsy confirmed her breast cancer diagnosis. She underwent a lumpectomy to remove the 4-centimeter tumor.

A lumpectomy is surgery to remove cancer or abnormal tissue from the breast. It’s also known as breast-conserving surgery because, unlike mastectomy, only the tumor and some surrounding tissues are removed.

Her cancer had spread to the lymph nodes, and her surgeon removed 14 of them. The surgery was followed by chemotherapy, which involves giving the cycles of certain chemo drugs closer together. She then received radiation treatment involving energy beams such as X-rays aimed at cancer cells to kill them.

In 2005, the singing cancer warrior bravely performed at the Grammy Awards while still bald from chemotherapy.

She said the morning of the awards show, she had undergone radiation treatment and felt weak.

“I remember halfway through, thinking in my mind, ‘Oh my God,” Etheridge said of her memorable yet inspiring performance.

Thankfully, her course of treatment proved to be successful and she’s still able to perform across the country with her most famous hits.

As for her experience with cannabis, Etheridge previously wrote in an article for CNN, “I had certainly encountered drugs during the ’80s, mostly cocaine, but nothing about grinding my teeth and rambling on about myself appealed to me. During the ‘90s, I smoked an occasional joint. Those were usually fun social occasions. My work was a drug-free zone.

“Then in 2004, I was diagnosed with breast cancer. The chemotherapy that was prescribed was called “dose dense”: a harsher, stronger chemo than the usual because I had the benefit of not having to work during the treatment. My close friends told me that, as an alternative, medical marijuana was a natural way to help with the excruciating side effects of chemo.”

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A post shared by Melissa Etheridge (@melissa_etheridge)

She insisted the cannabis use “worked” and “the entire experience changed my life.”

Etheridge explained, “It opened my mind to a new way of thinking about my body, my health and the future. This herb, this weed that is so strong it grows wild by the side of the road, has always been with us. In ancient times it was highly regarded and has even been found in tombs. It has even been put forth from some biblical scholars that Jesus may have used cannabis oil to heal.”

She later added, in the 2012 opinion piece, “I have been a medicinal marijuana smoker for nine years now. I find relief from the gastrointestinal effects of the chemo even now.

“I find it helps with regulating my sleep. I also enjoy it before I watch ‘Game of Thrones.'”

Treating Chemo Side Effects With Cannabis

Experts say cannabis can help patients cope with symptoms, including pain, but it is not a cure for their diagnosis.

“Medical cannabis, if you think about it, it’s the only botanical medicine that can help nausea, increase appetite, decrease pain, and elevate mood,” says Dr. Junella Chin, a integrative cannabis physician in New York, told SurvivorNet in an earlier interview.

A lot of people who are undergoing chemotherapy as part of their cancer treatment and  are using it for relief. Dr. Chin says that people come to her seeking relief for all types of chemo-related ailments, such as neasea, decreased appetite, pain, insomnia, or depression.

Some physicians will prescribe Marinol, or synthetic cannabis, to treat these side effects. But Dr. Chin says using the actual cannabis plant is simply more helpful. “That is much more effective in increasing appetite and decreasing pain for my cancer patients,” she explains.

“Integrative therapy is when patients come to see me when they want to add alternative or complementary therapies to their conventional treatments,” Dr. Chin told SurvivorNet.

Dr. Chin explains that many people working through pain and side effects associated with their diagnosis have likely tried other traditional methods before resorting to medical marijuana.

WATCH: Using marijuana to alleviate symptoms. 

“When you take plant-based cannabis, marijuana, you’re decreasing inflammation, and you’re relieving pain at the same time,” Dr. Chin says.

The human body contains an endocannabinoid system that helps us deal with chronic pain. However, sometimes, this natural system just isn’t enough to cope with the pain; hence, pain-relieving treatments and methods exist.

Dr. Chin adds that phytocannabinoids from the cannabis plant help replenish the body’s natural cannabinoid system, aiding pain management and inflammation.

What Are the Risks of Smoking Cannabis?

A recent study found that people who smoke cannabis tend to have higher amounts of toxic metals such as lead and cadmium in their blood and urine. These metals impact the brain and cause kidney and heart problems. Cadmium is also known to cause cancer.

Furthermore, SurvivorNet experts such as Dr. Raja Flores say smoking cannabis can be linked to lung cancer, and its smoke may contain the same carcinogens as cigarettes. Despite these risks, some cancer patients continue using cannabis to deal with symptoms or side effects associated with chemotherapy, which may include nausea and pain.

Dr. Raja Flores breaks down risk associated with smoking marijuana. 

About 40% of breast cancer patients use cannabis, according to a 2021 study, and most patients who use the drug report doing so to relieve symptoms associated with treatment, such as pain, anxiety, insomnia, and nausea/vomiting.

The new study that evaluated more than 7,000 people between 2005 and 2018 measured levels of five metals in their blood and 16 in their urine. They found that people who used marijuana had “significantly higher lead and cadmium levels in blood and urine than people who didn’t use [cannabis].” These toxic metals are also found in some cigarettes.

Despite the claims cannabis may benefit some cancer patients, many experts we spoke to urged against it, including Dr. Raja Flores, who is the Chairman of the Department of Thoracic Surgery for Mount Sinai Health System.

“As someone on the front lines, who sees this every day, I’ve seen lung cancer caused by marijuana that is incredibly aggressive,” Dr. Flores tells SurvivorNet.

“There is no real good population-based study that looks at marijuana smoking, and that has had enough time elapsed to show it’s associated with lung cancer, [but] I’ve seen it. I’ve seen multiple multiple cases of it. I see it every day,” Dr. Flores says.

RELATED: Can Marijuana Cause Cancer?

Contributing: SurvivorNet Staff

Learn more about SurvivorNet's rigorous medical review process.

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