TRUE OR FALSE. Can cancers develop because of emotional shocks?

After the announcement of King Charles III’s cancer, royal specialist Stéphane a Bern said in an interview with “Parisien”: “We know that cancers can develop through emotional shocks.” In the current state of knowledge, there is nothing to establish such a cause and effect link.

The English are “shocked” after the announcement of King Charles III’s cancer. The British sovereign began a “regular treatment program” to fight a “form of cancer, Buckingham Palace said on Monday February 5. In a newspaper interview The Parisianthe specialist in royalty, Stéphane Bern, reacts and affirms: “We know that cancers can develop through emotional shock. And, with Harry, the ordeal was very painful”.

The quote is then included in the title of the article and shared on social networks. The reactions are not long in coming. His comments are controversial, so much so that Stéphane Bern explained himself. “I never said that the king’s cancer was due to problems with his son Harry. I know from those close to him that he painfully experienced the death of his parents and the estrangement from his son whom he loves dearly”, he writes on X. Can cancers really appear due to emotional shocks? Franceinfo takes stock.

No scientific evidence of a cause and effect link between stress and cancer

In the current state of scientific knowledge, there is nothing to establish a causal link between emotional shock, stress and cancer. “To date, there is no scientific evidence of a causal link between stress and cancer […] Numerous scientific studies have explored this commonly held hypothesis, but they have not been able to conclude that psychological factors play a direct role in the appearance of cancer.writes the National Cancer Institute. “The influence of stress on the appearance of cancer has never been proven”specifies for its part the League against cancer. “Today no data indicates a link between a traumatic event and the appearance of cancer”insists the president of the French Cancer Society, Manuel Rodrigues, for franceinfo.

Dozens of studies have been carried out on the subject, but the results are contradictory. No scientific consensus is emerging. In 2019, Polish, English and American researchers compiled and analyzed 35 different publications on the subject. They were interested in studies on traumatic events, anxiety, chronic stress and work stress in the onset of cancer but also in the evolution of the disease. “The results of previous publications do not show strong evidence to associate psychological stress and cancer risk”write the authors, even if “chronic stress may play a role in the progression of cancer”. In detail, some studies show an association between traumatic events or stress and the appearance of cancer, other studies have demonstrated the opposite and some show no link.

The lack of consensus

In 2009, a similar study compiled more than 30 different publications under the title: “Is there a link between a psychological event and the risk of developing cancer?”. “In total, 18 studies out of the 32 retained do not show a link between psychological factors and cancer risk, six studies only show an association in certain subgroups and four surveys, including three by the same author, show an inverse link for female cancersconclude the authors.

In cases where a link has been shown between emotional shock and the appearance of cancer, the results should be taken with caution. “There are significant cognitive biases”explains Manuel Rodrigues, oncologist and president of the French Cancer Society. “When we ask a patient who has just been diagnosed if they have experienced a psychological shock in the preceding months, they almost systematically find a traumatic event”, continues the specialist. This makes the precise study of the psychological factor in the appearance of cancer all the more difficult. It is also complicated to eliminate all other factors to analyze only the role of stress or emotional shock, whereas cancer is often multifactorial.

Some 40% of cancers have an identifiable cause

“It takes several years for cancer to appear, so it is in any case impossible to say that an emotional shock that occurred a few months previously could have caused the disease,” adds Manuel Rodrigues.

Specialists nevertheless recognize the indirect role that stress can play. Some people, under stress, smoke more, drink more alcohol or eat less healthily. An impact of these factors on the risk of cancer has been well demonstrated. Some 40% of cancers have an identifiable cause: lifestyle, exposure to the sun or exposure to harmful products.