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People facing cancer are often searching for hope, especially when the disease gets worse or treatments stop working. But some online stories about ¡°miracle¡± cancer cures can be misleading and even dangerous. You may have questions about recent stories of people using a medicine called fenbendazole to treat their cancer. Here¡¯s what you should know.

Reports on alternative treatments can spread quickly, even when those treatments have not been scientifically tested. Some stories may leave out key details. Cancer news that sounds too good to be true could, in fact, be misinformation.

¡°It can be time-consuming and difficult for a patient to make sense of all the cancer information out there. We¡¯re here to help you make informed decisions based on the best available evidence and scientific data,¡± said Petros Grivas, MD, PhD, an expert and researcher at Fred Hutch Cancer Center and the University of Washington.

What is fenbendazole?

Fenbendazole has gotten a lot of attention in recent years. It is a deworming medicine that treats infections caused by parasites in animals, including dogs, cattle, goats, and horses.

The problem is that fenbendazole has not been tested in human studies. It is intended for use in animals only. The US Food and Drug Administration (FDA) has never approved fenbendazole for humans for any purpose.

Experts agree that scientific data does not exist about whether fenbendazole is safe and effective for people. While some individuals, websites, and social media may promote fenbendazole as a cancer treatment, the information provided is not supported by data and facts. With no solid proof behind these statements, the claims can give people false hope and can potentially cause harm.

The news about fenbendazole and cancer

Fenbendazole belongs to a group of medicines called anthelmintics that are used to treat parasites, including worms. Some research in humans has shown that certain other anthelmintics may help stop the growth and spread of cancer cells when combined with cancer treatments that are known to be effective. But the effect of anthelmintics on patient outcomes is unclear.

The limited research is one reason some people with cancer might decide to take fenbendazole on their own without informing their cancer care team. People have self-reported becoming ¡°cancer-free¡± after taking fenbendazole for breast, prostate, skin, and other cancers. But in most cases, the patients took fenbendazole at the same time as standard or traditional cancer treatments. In one popular story, a man claimed that fenbendazole cured his lung cancer. However, while taking it, he was also participating in a clinical research study of an immunotherapy treatment that is FDA-approved for treating the type of lung cancer he had.

These personal ¡°success¡± stories can sound compelling, but they do not prove fenbendazole is a safe and effective cancer treatment. It¡¯s impossible to know whether each person¡¯s outcome was due to fenbendazole or something else, including the other treatments they were taking for their cancer.

Why clinical trials are important

Clinical trials play a central role in medicine and cancer research. All new medicines, treatments, and procedures must go through rigorous testing before they are approved for use in the US. It usually takes more than one study to prove whether a treatment is safe and works well. ¡°Many promising drugs don¡¯t even make it to the final stage of clinical testing because of concerns about their safety and effectiveness,¡± Dr. Grivas said.

Laboratory studies of fenbendazole and other anthelmintic drugs have shown some early promise against a variety of cancers. But treatment that works against cancer cells in a petri dish or in animals doesn¡¯t always work in people. The results from human studies are still very early and mixed. Much more research is needed to answer key questions about fenbendazole, including:

• Is it safe for humans?
• What are the appropriate doses for humans?
• How effective is it against cancer compared to standard treatments?
• Which types of cancer might it work best for?
• Which groups of people might benefit the most?
• Does it have the potential to interact with other cancer treatments?

Risks of taking fenbendazole

When making treatment decisions, it¡¯s important to understand risk versus benefit. For fenbendazole, the risks include:

• Taking a drug intended only for animals can be unsafe.
• Alternative therapies, such as fenbendazole, might interact with prescribed standard treatments. This might reduce their effectiveness and/or raise safety concerns.
• Trying something new without your doctor¡¯s knowledge could harm your health and make it harder for your doctor to provide the care you need.
• Inflammation and liver damage are two side effects reported in the few case studies of people with cancer who have taken fenbendazole.

These factors can make it challenging for your cancer team to manage your care, Dr. Grivas noted. ¡°In the case of fenbendazole, there is no proven benefit but several potential risks. That¡¯s why I do not prescribe fenbendazole or any other unproven medication,¡± he said.

How to make sense of news about cancer treatment

When learning about cancer treatments, look for trustworthy sources of information. Peer-reviewed journals, major news outlets, government agencies, universities, and nonprofit organizations are generally considered reliable sources of medical news and research. If you¡¯re looking at a particular clinical trial, consider the size of the cancer study, how it was conducted, who paid for it, and how many other studies had similar results.

If you¡¯re curious about a new cancer treatment, talk with your care team. Ask them:

• Do you recommend this treatment for me? Why or why not?
• What evidence is there that this treatment is safe and effective for my type of cancer?
• What are the potential benefits and risks of this treatment?
• Am I eligible to participate in a clinical trial?
• Where can I go to get reliable information about cancer treatment?

¡°Come with your questions. New treatments are not taboo. We understand you are trying to advocate for yourself or your loved one,¡± said Dr. Grivas. ¡°Your doctor is on your side, and they want the same thing as you: to help you live longer and with a better quality of life.¡±

Learn more about cancer treatment and clinical trials from the ºÚÁÏ´óʪPosts Cancer Society:

• How to Interpret News About Cancer Treatments
• Types of Cancer Treatment
• Making Treatment Decisions
• How to Use Integrative Therapies Safely
• Clinical Trials

Dr. Grivas is a member of .