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Woman's Shrinking Tumor Has Doctors Asking If CBD Oil Is Responsible


Rachael Funnell

Digital Content Producer

clockOct 18 2021, 16:42 UTC
CBD oil lung tumor

The case study alone is not evidence for CBD oil as an effective cancer treatment but highlights that it could be a worthy avenue for further research. Image credit: elizabethmphl /

A new case study has suggested that cannabidiol (CBD) as an alternative cancer therapy may warrant further research, after an 80-year-old smoker’s lung tumor shrank despite declining medical treatment. The patient had been self-administering CBD oil several times daily for a period of 2.5 years, during which time a cancerous tumor in her lung shrank to a quarter of its original size. While it can’t be concluded that this patient’s improvement was down to CBD oil use, the authors say it’s possible a connection exists, warranting further research into the effects, if any, of CBD oil on cancerous tumors.

The intriguing case study was published in BMJ Case Reports and details the disease progression of an 80-year-old woman who was a regular smoker and had been diagnosed with lung cancer. At time of diagnosis, the patient was offered several conventional treatments to tackle the tumor but declined in favor of “watchful waiting” whereby her condition would be left unchanged but monitored by medical professionals to keep tabs on any significant changes.


Unbeknownst to their medical team, the patient self-prescribed CBD oil two to three times daily after a family member recommended it. Interestingly, despite turning down medical interventions and continuing to smoke throughout the 2.5 year surveillance period, the cancerous tumor shrank progressively from 41 millimeters (1.6 inches) in June 2018 to 10 millimeters (0.4 inches) in February 2021, an overall 76% reduction. During their “treatment time,” the patient experienced no significant side effects other than a slight loss of appetite which may or may not be the result of the CBD oil.

CBD and THC are two ingredients found in cannabis, being non-psychoactive and psychoactive respectively. According to the supplier of this patient’s CBD oil, the active ingredients were roughly equal amounts of THC and CBD, but the researchers were unable to confirm the full ingredients. The patient also reported taking inconsistent dosages, making the exact “treatment regime” difficult to replicate.

As for evidence for the oil playing an instrumental role in the radical tumor shrinkage, the existing body of research isn’t terribly definitive one way or the other. For a long time, scientists only had cultured cell and animal research to work from, limiting the findings’ generalizability. In 2021, this changed as it was announced that a cannabis-based mouth spray would be tested as a potential treatment for glioblastoma brain tumors, marking the first-ever major human trial involving medical cannabis as a cancer therapy.

Without a significant body of research based on human trials to work from, it would be inaccurate and unwise to draw any sweeping conclusions from individual case reports such as this one. However, as the researchers explain, given the known and severe side effects of conventional interventions such as chemotherapy, radiotherapy, and surgery, it’s worth investigating alternatives that could provide hope for a less grueling treatment plan.


“Existing cancer treatments could have severe side effects, both physically and mentally,” they wrote. “This is why our patient decided on non-conventional self-treatment. The limited number of case reports appear to show that ‘CBD oil’ can have positive effects on tumour reduction. More research is needed to identify the actual mechanism of action, administration pathways, safe dosages, its effects on different types of cancer and any potential adverse side effects when using cannabinoids.

“The potential for cannabinoids to be used as an alternative to augment or replace conventional primary cancer treatments definitely justifies further research.”

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