- A case study links daily use of cannabidiol (CBD) oil with lung cancer regression in a woman in her 80s who refused conventional treatment.
- Researchers cannot definitively confirm that CBD oil caused tumor reduction.
- More research is necessary to define the mechanism of action, effects on different types of cancer, adverse reactions, and optimal dosage and routes of administration.
CBD and delta-9-tetrahydrocannabinol (THC) are the two major cannabinoids present in the cannabis plant. However, CBD does not produce a euphoric feeling, or “high,” that people associate with cannabis use.
CBD oil is a concentrated extract derived from cannabis leaves or flowers dissolved in a consumable oil, such as olive, hemp, or sunflower oil. There are different types of CBD oil containing various concentrations of cannabinoids.
Broad-spectrum CBD products include most of the same compounds as full-spectrum ones but only trace amounts of THC.
Full- and broad-spectrum products may produce greater clinical effects than CBD isolates due to the entourage effect — the combination of cannabinoids has a more pronounced impact than individual ones.
Cannabinoids interact with the body’s internal cannabinoid system, which experts call endocannabinoid system. This system modulates:
Doctors in the United Kingdom recently published an article in the journal BMJ Case Reports. The case report describes a woman in her 80s with lung cancer who experienced tumor regression while taking CBD oil.
The woman reported smoking just over a pack of cigarettes per week, or 68 packs per year, before and after diagnosis. In June and July 2018, doctors examined the woman, which included a CT scan, a PET scan, an MRI scan, and a biopsy, to stage and confirm the diagnosis.
The doctors reached a diagnosis of
Testing revealed no lymph node involvement or metastases, which is when cancer spreads to other parts of the body. For this reason, the doctors recommended curative treatment.
The doctors repeated the chest CT scan in September 2018, which showed a reduction of the right middle lobe cancer to 33 mm (1.3 in), and two new nodules in the left apex and right upper lobe.
The woman declined surgical removal of the lobe due to the risks of surgery. She also declined treatment with radiofrequency ablation because of the side effects that her late husband had experienced from radiation therapy.
The doctors decided to monitor the patient, conducting CT scans every 3–6 months. During the 2.5-year follow-up period, CT scans showed a progressive decrease of the initial right middle lobe nodule from 41 mm (1.6 in) in June 2018 to 10 mm (0.4 in) in February 2021.
At this time, the woman revealed she started taking CBD oil at a dose of 0.5 milliliters orally three times daily, and occasionally twice daily, shortly after her diagnosis.
The active ingredients specified by the supplier were THC (19.5%), CBD (20.05%), and tetrahydrocannabinolic acid (23.8%).
Upon the supplier’s advice, the woman did not take the CBD oil with hot food or drinks, because she wanted to avoid “feeling stoned.” She reported decreased appetite while taking CBD oil.
The woman did not change her diet, lifestyle, or prescribed medications during this time. She also reported continuing to smoke one pack of cigarettes per week during the surveillance period.
In an interview with Medical News Today, the lead author, Dr. Kah Ling Liew at the Respiratory Department of Princess Alexandra Hospital in the U.K., commented:
“We were definitely not expecting to see such a striking tumor regression with no conventional cancer treatments and no other health or lifestyle changes. […] Multiple studies so far in animal models have shown conflicting results, with some cases reducing cancer cell growth and others finding an accelerating growth of cancer cells.”
MNT also spoke with Dr. Jack Jacoub, a medical oncologist and medical director of MemorialCare Cancer Institute at Orange Coast Medical Center in Fountain Valley, CA.
Dr. Jacoub, who was not involved in the study, said: “It’s definitely hypothesis provoking, and additional research is needed before it could become a recommended [treatment] option for patients with cancer. From the strength of scientific evidence standpoint, a case report is about the weakest strength, and so you have to consider what you’re reading in that context.”
He emphasized the need for randomized controlled clinical trials to confirm the safety and efficacy of CBD oil to treat cancer. Dr. Jacoub explained: “You enroll patients [meeting preset criteria] and watch what happens to their disease, their progression-free survival, and all the endpoints typically in oncology trials. That is […] the only way I could see [CBD oil] being mainstream [treatment].”
Dr. Liew added: “The optimal dosage, form, route of administration, and combination of CBD/THC for each specific type of cancer — brain, lung, liver, prostate, and so on — needs to be further researched and determined. There will not be a single treatment that works for every form of cancer.”
Dr. Liew told MNT, “Future studies need to be mindful of potential ingredient inconsistencies between CBD oils, and ensure […] when replicating studies that identical components are used.”
Dr. Liew continued: “Clinicians need to be aware that their patients may be taking nonconventional and unlicensed treatments without their knowledge. It is always important to take into account a patient’s choices when discussing treatment options, that is, being open and honest about potential benefits and side effects of treatments.”