A Woman’s CBD Habit May Have Shrunk Her Lung Tumor, Say Doctors

In recent years, following the retail rise of CBD and cannabis products, there has been a small but alarming trend of cancer patients shunning conventional chemotherapy and radiotherapy and treating their tumors with such cannabis-based products.

Many doctors have warned against the practice, citing the deadly health risks of eschewing proven medical treatments for cancer.

But, according to a new clinical case study, one woman may have just proven the doubters wrong.

Published in the British Medical Journal Case Reports, the case study followed one woman in her 80s who had been diagnosed with lung cancer but had refused surgery, chemotherapy, or radiotherapy. Instead, she took oral drops of cannabis oil. Almost three years on from her diagnosis, the researchers say the woman’s tumor had shrunk by 76 percent.

One drop at a time

According to the case study, the woman was diagnosed with a lesion measuring 41 millimeters (mm) on her lung in June 2018, after she went to her general practitioner doctor with concerns about a persistent cough.

She was a regular smoker (getting through around 68 cigarette packs per year) and had a clinical history of mild chronic obstructive pulmonary disease.

She was referred onto other specialists and offered radiotherapy and surgery, which she both declined. She was advised to quit smoking but continued with her habit. Regardless, her doctors agreed to monitor her via regular computed tomography (CT) scans.

It was through these regular scans that the doctors observed the patient’s tumor depleting in size. By February 2021, the initial 41 mm lesion had been reduced to 10 mm – an overall 76 percent reduction in maximum diameter.

Flummoxed, the doctors approached the patient to discuss her results. It was during this consultation that she disclosed that she had been taking “CBD oil” around twice a day every few days since she had declined conventional treatments. The oil, which was obtained from outside the UK, was advertised as containing 20.05 percent CBD, 19.5 percent THC, and 23.8 percent THCA.

Other than a slightly reduced appetite, the patient reported no side effects.

While the authors acknowledge the case study’s limitations – namely, that only one patient was monitored, and that the doctors were unable to verify the content of the cannabis oil – they do acknowledge that the oil’s “ingredient(s) may be contributing to the observed tumour regression.”

“Although there appears to be a relationship between the intake of ‘CBD oil’ and the observed tumour regression, we are unable to conclusively confirm that the tumour regression is due to the patient taking ‘CBD oil’,” they wrote in the case study.

CBD and cancer

Medical cannabis is largely known for its associations with pain management and the treatment of certain epilepsies. But there is a growing research field investigating the effect cannabinoids can have on tumors and cancers.

One 2017 paper, for instance, demonstrated that high doses of CBD and THC could significantly regress tumors in animal models. Another 2018 study showed that when treated with cannabis compounds and chemotherapy, mice with pancreatic cancer survived almost three times longer than those treated with chemotherapy alone. 

But other studies have been less promising. In a 2019 paper, CBD was found to reduce the size of tumors in mice, but the cannabinoid’s effects still paled in comparison to cisplatin’s, a more conventional chemotherapy medication.  

Concerningly, other studies have found that, in some contexts, cannabinoids seem to increase the growth of certain cancers. A study published in 2020 found that marijuana use may be a driving factor in the rise of head and neck cancers in the US. In that study, the researchers observed that THC can activate a molecular mechanism in the body that accelerates tumor growth in patients with human papillomavirus (HPV)-positive skin cancers.

Lung cancers, on the other hand, appear to have a null association with cannabis use, despite the presence of carcinogens in cannabis smoke. As for the reasons behind this null effect, one scientific review published in 2015 posited that cannabinoids like THC counteract the carcinogens with their known tumor-suppressant effects.

Ultimately, many researchers and oncologists agree that more research is needed before a consensus can be made on cannabis’ clinical effect on reducing tumors. What is more agreed upon, however, is marijuana’s effect on treating the side effects of chemotherapy and radiotherapy.

“I write on whether oncologists should recommend cannabis and I'm a very strong proponent of it, because a day doesn't go by that I don't see a cancer patient with nausea, loss of appetite, pain, insomnia, depression, and I can recommend one medicine to those patients,” Donald Abrams, a doctor and professor of clinical medicine at the University of California, San Francisco, told Analytical Cannabis in 2019.

“And [cannabis] is less likely to interact with the other medications that I prescribe or my chemotherapy than standard pharmaceuticals. So, I am a huge proponent of the benefits of cannabis in symptom management.”

“What pains me is people forgoing conventional therapy that may benefit them greatly and even cure them, in favor of using these products that have absolutely no evidence to support their use,” he added. “And in San Francisco, patients pay up to $7,000 a month for these products. I just find it criminal and tragic.”

“As an oncologist in San Francisco for the past forty years, I have to say, if cannabis cured cancer, I would certainly have a lot more survivors.”