Cancer, an old enemy that little by little reveals its secrets

Cancer, that old enemy of the human species, has been revealing its secrets, thanks to the spectacular advances in medicine, but the field of research is still immense.

The disease is caused by the transformation of cells, which proliferate in an abnormal and uncontrolled way. It is estimated to cause around 10 million deaths a year worldwide.

After decades of intense research, its origins and characteristics are much better understood. It is now known, for example, that there is not “one” cancer for an organ, but that it can manifest itself in different ways. And that the same type of cancer can cause different tumors.

“Talking about colon cancer, or breast cancer, doesn’t mean anything: the challenge today is to define what cancer looks like from a biological point of view”, explains the director of research at the French specialized center Gustave- Roussy, physician Fabrice André, told AFP.

There are, for example, three major classes of breast cancer that do not all respond in the same way to the same treatment.

In recent years, “the development of molecular technologies has made it possible to better identify which are the abnormal proteins that must be stopped” for each type of tumor, adds André.

This better understanding of the disease allowed the emergence, in the 2000s, of selective therapies, whose target is a particular genetic mutation.

Immunotherapy

Chemotherapy was for years the only viable treatment, without focusing on the specific affected area. Side effects were often severe.

For some types of cancer, such as certain leukemias, “selective therapies were a revolution”, points out Bruno Quesnel, director of research and innovation at the National Cancer Institute (Inca), in France.

In the last decade, it was immunotherapy that brought the most important advances to oncology. Its principle is that the patient becomes his own medicine.

Unlike chemotherapy, the cancer cells themselves are no longer attacked. What is done is to reinforce the immune cells that surround them, so that they destroy the cancerous ones.

With this discovery, James Allison of the University of Texas and Tasuku Honjo of Kyoto University won the Nobel Prize in Medicine in 2018. In the case of some types of cancer, the discovery was crucial.

Prior to 2010, for example, the chances of survival from metastatic melanoma (the most serious skin cancer) were very low. Thanks to immunotherapy, life expectancy has increased to ten years instead of just a few months.

Not all tumors respond positively to this treatment, which can also cause side effects.

Artificial intelligence

“We are just at the beginning of immunotherapy”, says Bruno Quesnel.

Its applications are varied: biospecific antibodies, cellular and allogeneic therapies (CAR-T cells), among others.

“Now it’s about getting the right combination of treatments,” says Pierre Saintigny, an oncologist at the Léon Bérard center in Lyon.

“With immunotherapy we have taken a step up in the treatment of cancer, but there are still many others left for those patients who do not have access” to this treatment, he says.

Researchers also have biotechnologies available to develop new drugs, which are increasingly more selective and less toxic.

And the latest weapon, newly arrived, is artificial intelligence (AI), which allows a better definition of cancer prognosis.

Thanks to it, “we will be able to identify which patients can benefit from a short treatment”, says Fabrice André.

Its main advantage is the progressive de-escalation of the treatment and, therefore, a reduction of costs.

The first cancer treated with the help of AI was breast cancer.

Another hope lies in the ability to detect a tumor in the body very early.

“It has already been achieved in the United States, by DNA tracking, based on a simple blood test, but many false positives still appear”, reports Fabrice André.

With the generalization of this technique, prevention would improve substantially, which is still the best way to avoid most cancers.