More than half of Croatians believe in the biggest conspiracy theory about cancer
Countries of Southeast Europe, including Croatia, are at the very top of European countries in terms of the share of people who believe in the conspiracy theory that a cure for cancer has already been found but is being hidden from the general population for profit.
According to Eurobarometer data on citizens' knowledge and attitudes towards science and technology, in North Macedonia as many as 72% of respondents believe that the claim about hiding a cure for cancer is true. In Turkey this share is 71%, in Albania 70%, in Kosovo 66%, in Bosnia and Herzegovina 64%, in Montenegro 62%, in Croatia 55%, in Serbia 51%, and in Slovenia 43%.
Scandinavians least prone to conspiracy theories
In the EU, Croatia is also very high. Ahead of us are Cyprus with 63%, Hungary with 58%, and Greece with 56%. For comparison, in Sweden and Denmark only 8% of respondents believe that a cure for cancer is being hidden from the public, and in Finland 10%. At the EU level, 34% of respondents consider this claim true, 55% say it is false, and 11% do not know the answer.
How do we know this is a conspiracy theory?
The problem with this conspiracy theory begins with the basic assumption. Namely, cancer is not a single disease. The US National Cancer Institute states that cancer is a group of related diseases that can occur almost anywhere in the body.
Cancer Research UK states that there are more than 200 types of cancer. Therefore, the idea of a single "cure for cancer" is essentially scientifically meaningless; it is like treating all infections, from tuberculosis to fungal nail infections to viral meningitis, with one antibiotic.
Differences are visible even under a microscope
The head of the Laboratory for Cancer Research at the Faculty of Medicine in Split, Janoš Terzić, says that lung cancer, breast cancer, leukemia, pancreatic cancer, melanoma, and testicular cancer are not the same disease.
"For example, lung tumors differ even when we look at them under a microscope. The cells are of different sizes and shapes, contain different immune cells, have different amounts of connective tissue, etc. There are even more differences when we analyze tumor genes or proteins. It is known that lung cancer can have tens of thousands of mutations, so it is obvious that no two lung cancers have the same set of mutations. The concept of one drug for all tumors is like fixing a punctured car tire and a fuel pump malfunction in the same way," explains Terzić.
Cancer drugs already exist and are being used
Another important fact is that numerous cancer drugs already exist and work very well for certain diseases.
The NCI lists several types of treatment, from surgery, radiation, and chemotherapy to immunotherapy, hormone therapy, hematopoietic stem cell transplantation, and targeted therapies.
For some types of cancer, progress in treatment is enormous. For example, for childhood acute lymphoblastic leukemia, the five-year survival rate for children under 15 has increased from about 60% to about 90%.
According to Cancer Research UK, for testicular cancer, the five-year survival rate exceeds 95%. Terzić says that some types of cancer are well treated, while others remain very deadly, especially when detected late.
"It is precisely this difference between very curable and very dangerous tumors that shows how wrong the idea of a single secret cure is. In reality, medical science does not hide one miraculous drug, but for decades has been developing increasingly precise therapies for various diseases that we colloquially call cancer," he adds.
It would be almost impossible to hide a cure for cancer
The theory of hiding a cure is also illogical for a practical reason. If someone really discovered a drug that cures all or most cancers, it is hard to imagine that they could or would want to hide it.
Such a discovery would bring them scientific fame, a Nobel Prize, enormous earnings, and scientific and political influence.
In addition, thousands of universities, hospitals, pharmaceutical companies, state institutes, non-profit organizations, and researchers around the world are involved in cancer research. For the theory to be accurate, all of them would have to remain silent, including doctors who treat their own family members daily and scientists who themselves develop cancer.
Scientific discoveries are published in journals
Such a conspiracy would be practically unfeasible because of the way science works. Research results are published in scientific journals, reviewed by other researchers, clinical trials involve hospitals, regulatory bodies, and patients, and new drugs go through approval procedures.
Pharmaceutical companies, of course, operate for profit, but a drug that dramatically improves cancer treatment would be one of the most profitable products in medical history. Therefore, the financial motive does not support hiding, but rather the race to develop, patent, and sell a good drug.
Why do so many people believe in this theory?
So why do so many people believe such a claim? Research shows that belief in conspiracy theories is not just a matter of ignorance.
A Croatian study published in the journal Frontiers in Psychology analyzed who believes in conspiracy theories about COVID-19. The authors found that distrust in science and scientists and a feeling of political powerlessness were the strongest predictors of belief in conspiracies. Belief was also associated with lower education, lower economic status, greater importance of religion, and a greater sense of powerlessness.
International research has shown a similar pattern. For example, a paper by Jan-Willem van Prooijen found that people with higher education are less likely to believe in conspiracy theories, but also that this relationship is not simple. Education is associated with analytical thinking, a lower sense of powerlessness, and a lower tendency toward simple explanations for complex problems.
Terzić says that some pharmaceutical companies have paid tens of billions of euros for some cancer drugs, so it is simply unbelievable that they would hide them instead of earning enormous sums from them.
"The theory of a hidden cure for cancer is a typical example of a simple explanation for a very complex problem. Cancer is difficult, frightening, and unfair, so people look for explanations why therapies are expensive, why some side effects are devastating, and why medicine still cannot save everyone. The conspiracy theory offers an emotionally appealing answer: the cure exists, but the powerful are hiding it. Science offers a less comforting but accurate answer: cancer is a group of very different diseases, progress exists, but it is not equal for all tumors and all patients," explains the Split scientist.
The importance of education and trust in authorities
In this context, it is interesting to see how Croatia stands on some broader indicators of scientific literacy. Namely, research shows that low scientific literacy, government corruption, and high religiosity are a kind of "fuel" for conspiracy theories. In Croatia, we have exactly that combination: We are below average in science, we are at the bottom of the EU in corruption, and a large percentage of citizens identify as religious.
Thus, PISA tests, which measure the ability of 15-year-olds to apply knowledge from mathematics, reading, and science in real-life situations, show that Croatia in 2022 scored 483 points in science, while the OECD average was 485.
At the same time, according to Transparency International, Croatia in the 2024 Corruption Perceptions Index had 47 out of 100 points and ranked 63rd out of 182 countries. The 2021 census showed that the vast majority of residents declared religious affiliation, including about 79% Catholics.
"It's not a matter of stupidity"
Terzić warns that this does not mean that people who believe in the conspiracy theory about a cure for cancer are simply "stupid."
"Such a conclusion would be incorrect and useless. Research points to a more complex problem. Therefore, the fight against such theories should not rely solely on ridicule and criticism. Much more effort and social engagement is needed. We need to work on improving education and scientific literacy, clearer presentation of medicine, greater transparency of health institutions, and open discussion about real problems, such as drug prices, unequal access to therapies, etc. In other words, belief in the 'hidden cure' is only a symptom of a more serious illness," says Terzić.
