Cancer is the body's defense against toxins?

We often witness such false claims being made on social media, where much of the content is not subject to any fact-checking. What do experts say about this topic? See a new article by Agence France-Presse (AFP) , a multilingual, multicultural news agency whose mission is to provide accurate, balanced and impartial continuous reporting wherever and whenever news happens in the world. Our oncologist Dr. Davor Kust also spoke for the article.

We are reposting the article in its entirety, and you can find the original at the link .

Cancer is a disease that kills nearly 10 million people a year, but available treatments can significantly increase the chances of survival. Despite this, a video has gone viral online in which a self-proclaimed mentalist claims that cancer is not a disease, but a survival mechanism that protects the body from toxins, and that most people do not die from cancer, but from its treatment. This is incorrect. Ample scientific evidence shows, and experts told AFP, that cancer is not a survival mechanism and can be a deadly disease, adding that most patients benefit from its treatment.

"Cancer is not a disease. It's a survival mechanism," the man claims in a video with Croatian subtitles posted on Instagram on March 1, 2025. The man further claims that a tumor is a place in the body that stores all the toxins that the body takes in through diet, lifestyle, and stress, and concludes that "actually most people don't die from cancer, they die from cancer treatment."

The Instagram video has garnered a lot of attention, garnering more than 9,000 likes in the three weeks since it was posted, with many comments supporting the influencer. "You're right, chemo only kills people," wrote one commenter. "Bravo, exactly," said another. "The treatment is worse than anything," added a third.

However, these claims are incorrect. A wealth of scientific evidence shows that cancer is a deadly disease, and official data shows it is the second leading cause of death in Croatia. Experts told AFP that this is not a defense mechanism and that the vast majority of patients benefit from cancer treatment.

Screenshot of an incorrect Instagram post, taken on March 19, 2025.

Using a reverse footage search, AFP determined that the clip being shared came from an episode of Sean Kelly's US podcast Digital Social Hour, broadcast in January 2024 . According to the episode's description, the man in the video is "mentalist Joshua Earp," who "does a deep dive into the intersection of ancient wisdom and modern marketing."

Earp presents himself as an "international celebrity, magician and mentalist," and also as a "world-renowned entrepreneur, investor, musician, search engine optimization expert and actor." There is no evidence that he has any education in medicine or biology.

Cancer is not a "defense mechanism"

Cancer is a group of diseases that can begin in almost any organ or tissue of the body when abnormal cells begin to grow uncontrollably, and is the second leading cause of death globally, with an estimated 9.6 million deaths in 2018.

It is also the second leading cause of death in Croatia, where 13,419 people died of cancer in 2023 , accounting for 26.17% of all deaths that year. Cancer mortality is the second highest in the European Union, according to the OECD and European Commission's 2025 Cancer Report. While the report estimates that health coverage is adequate for the country's needs, it highlights that Croatians are in the bottom third of the EU in five of the nine main risk factors for cancer – smoking, obesity, low physical activity, occupational exposure and air pollution.

"Cancer is definitely not a defense mechanism of the body," oncologist Davor Kust , head of the Anova clinic and founder of the oncology network onkologija.net in Croatia, told AFP by telephone on March 19, 2025. "Because then the question arises why would the patient die?" Kust told AFP that cancers do not form around "toxins," although environmental factors can increase the risk of developing cancer. "There is no way for us to live healthy – without toxins, so to speak – and be safe from getting sick. Cancer can occur in anyone, no matter how healthy they live."

"Cancer is the price that multicellular organisms pay for their multicellularity," said Vanda Juranić Lisnić , a biomedical expert at the University of Rijeka's Faculty of Medicine , in an email to AFP on March 25. "As in society, the cells of our body must cooperate with others and sometimes sacrifice themselves for the greater good. Cancer is a population of cells that no longer cooperate for the good of the whole organism, but divide uncontrollably even when there is no need for it, even when it leads to their death (either because the tumor has grown so much that the oxygen/food supply is compromised, or because the tumor has killed the host)." "The claims that tumors take toxins from the body are completely wrong," Juranić Lisnić stressed. "Our body has several organs that deal with removing toxins from the body, they certainly don't need a tumor for that."

Later in the video, Earp also incorrectly claims that the first thing doctors do is a biopsy – taking a small sample of tumor tissue to look at under a microscope – which, he believes, is unnecessary for cancer patients. “Whether your tumor is ‘cancerous’ or not, your treatment path is the same,” Earp says. A tumor is a rapidly growing group of cells , but not all tumors are the same – some are not life-threatening. Depending on the type of tumor, patients may be treated with surgery, chemotherapy or radiation . Benign tumors do not always require treatment. Oncologists decide on the need for a biopsy on a case-by-case basis, depending on the severity of the disease.

Treatment improves the chances of survival

"There are a lot of patients who are not treated and are not doing well," Kust told AFP. "Everything we do is based on some kind of scientific fact." According to him, people should accept cancer treatment "because we know that then the results are better." "Nobody is cured spontaneously, I have not seen it. If the disease is not curable, then these patients [who are treated] live longer and better."

Kust also pointed out that chemotherapy, a powerful drug used to kill cancer cells, has a bad reputation for unpleasant side effects (nausea, pain, hair loss, and others), but that's because chemotherapy is mostly given to patients with more severe forms of the disease. He noted that a small number of patients can develop serious side effects from the therapy, which can lead to death, but that this doesn't happen often. "If we take a large number of patients, then the largest number of patients benefit from this therapy."

Kust added that while chemotherapy itself has not advanced significantly in the past decade, there have been major advances in supportive care drugs - which are given alongside the main treatment to help with side effects, such as pain or nausea. "The side effects are much less, and patients have a much better quality of life," Kust said.

Speaking to AFP in December 2024, Kust said that cancer treatment, including chemotherapy, is based on serious scientific research. "All oncology therapies have undergone fairly rigorous and uniform clinical studies, which provide fairly objective and realistic data that can be trusted," Kust said.

"Cancer treatment is difficult because you are fighting your own cells, so it is difficult to find a therapy that will target only the tumor cells, but not other, healthy cells," Juranić Lisnić told AFP. "However, the claim that most people die from cancer treatment is unfounded and very easy to verify." "I myself underwent treatment for Hodgkin lymphoma, and that was more than 15 years ago," said Juranić Lisnić, speaking of the type of cancer that affects white blood cells . "Just a few decades ago, these lymphomas were fatal, but today they are among the most curable tumors."

A wealth of scientific evidence shows that treatment significantly increases survival rates. For example, a 2022 study looking at head and neck cancer found that untreated patients had a median survival time of 12 months, compared to 100 months for treated patients. A 2021 study on endometrial cancer found that patients over the age of 40 had significantly higher survival rates after surgery, compared to those who refused treatment. Another 2021 study on metastatic breast cancer also found that untreated patients had a median overall survival time of 2.5 months, compared to 36.4 months for treated patients.

In the long term, improvements in early detection and treatment of cancer have led to a 33% decline in cancer deaths in the US since 1991. Similarly, in the UK, the proportion of people surviving at least 10 years after diagnosis exceeded 50% in 2018 , compared with around 24% in the early 1970s. A 2025 report by the Swedish Institute of Health Economics (IHE) also showed significant improvements in cancer survival rates between 2000 and 2010 in EU countries for which data from national cancer registries were available.