Woman's Lung Cancer Shrinking After She Took CBD Oil Prompts Caution From Scientists

Scientists have advised caution after a report emerged of a woman whose lung cancer tumor shrank after she took regular doses of CBD oil.

CBD oil, which is a non-psychoactive chemical extracted from the hemp or cannabis plant, is linked to several possible health benefits such as pain relief and anxiety reduction.

People have also wondered whether CBD could be used as a cancer treatment, but this link remains inconclusive, according to MedicalNewsToday.

A case report was published in the British Medical Journal on October 14 involving a woman in her 80s who was diagnosed with lung cancer in 2018 after she went to doctors with a persistent cough.

The woman, a 68-pack-a-year smoker, was offered treatment for her cancer including surgery and radiotherapy, but she declined both, so doctors decided to simply watch and wait by carrying out regular scans.

According to the case report, regular CT scans over the following two-and-a-half years showed that her lung tumor appeared to be shrinking over time, despite the fact that the woman was continuing to smoke and was not receiving any conventional treatment.

The lesion in her lungs was measured at 41 millimeters in June 2018 and had reduced to 10 millimeters by February 2021.

When doctors contacted her to discuss this, she revealed that she had been taking "CBD oil" as a self-treatment after being advised to do so by a family member shortly after her 2018 diagnosis.

The woman was taking 0.5 milliliters of the oil two to three times per day by ingesting it. The case report authors note that the oil "appears to have had a positive effect on her disease" but couldn't conclusively confirm this.

"Although there is clearly a potential for cannabinoids to be used as a primary or as an adjunct form of cancer treatment, further research is required to identify exactly which compound works against which specific cancer cell type," the report states.

It also notes that previous studies have "failed to agree on the usefulness of cannabinoids as a cancer treatment."

Meanwhile, scientists not involved in the case report have said that while the case appears encouraging, it should be taken with caution.

Professor David Nutt, The Edmond J Safra Chair in Neuropsychopharmacology at Imperial College London, told the Science Media Centre (SMC) that the example is "one of many such promising single case reports of medical cannabis self-treatment for various cancers," but added: "A case report itself is not sufficient to give any form of proof that one thing caused the other—we need trials for that."

Professor Edzard Ernst, Emeritus Professor of Complementary Medicine at the University of Exeter, echoed the point, telling the SMC that while some case reports into cancer and cannabis extracts have been encouraging, "case reports cannot be considered to be reliable evidence."

One other issue with this case was that the woman had used CBD oil that also contained THC—the chemical in cannabis that causes people to feel high.

"This type of product is very different to most CBD oils which predominantly contain CBD," Dr. Tom Freeman, senior lecturer and director of the Addiction and Mental Health Group at the University of Bath, told SMC.

Indeed, the case report authors note that it is difficult to conclude whether the THC in the woman's oil contributed to the tumor reduction or if it was just the CBD component that may have had a positive effect.

Freeman added that "people with lung cancer should always seek guidance from a healthcare professional."

CBD oil
A stock photo shows a small bottle of oil against a backdrop of cannabis plants. CBD, which can take the form of oil, has been linked to various potential health benefits but it is still not known whether it can be used to treat cancer. Tinnakorn Jorruang/Getty