Cancer: better understanding the disease to advance research

Caused by the transformation of cells that become abnormal and proliferate excessively, cancer is a scourge as old as life.

Identify abnormalities specific to each cancer

But progress in research has made it possible to better understand this disease, the cause of nearly 10 million deaths per year worldwide: we now know that for the same organ, there is not “one” but “of” cancers. And that for the same type of cancer, there can be different tumors.

“Talking about colon cancer or breast cancer means nothing; the challenge today is to define what cancer looks like biologically”explains to AFP the doctor Fabrice André, director of research at the Gustave-Roussy anti-cancer center.

There are, for example, three main types of breast cancer, which are not receptive to the same treatments.

These last years, “the development of molecular technologies has made it possible to better identify which are the abnormal proteins to be blocked” for each type of tumour, continues Professor André.

This better understanding of the disease led to the emergence, in the 2000s, of targeted therapies targeting a specific genetic mutation.

After targeted therapies, the immunotherapy revolution

Previously, chemotherapy was often the only treatment offered: but by aiming to eliminate cancer cells, regardless of their location in the human body, it could cause side effects.

For several types of cancer, such as certain forms of leukaemia, “targeted therapies have been a revolution”emphasizes Professor Bruno Quesnel, director of research and innovation at the National Cancer Institute (Inca).

Over the past ten years, immunotherapy has emerged as the most important progress in oncology.

The principle: the patient becomes his own medicine. Unlike chemotherapy, we no longer target the cancer cells themselves but the immune cells that surround them in order to activate them. Reboosted, it is the latter that destroy the tumor cells.

This discovery won the 2018 Nobel Prize in Physiology and Medicine for James Allison of the University of Texas and Tasuku Honjo of Kyoto University.

For some cancers, this discovery was major. For example, before 2010, the survival rate for patients with metastatic melanoma (the most serious skin cancer) was very low. Thanks to immunotherapy, life expectancy has increased by up to ten years, compared to a few months previously.

But not all tumors respond to this treatment, which can also cause side effects.

Artificial intelligence to improve care

“We are only at the beginning of immunotherapy”, assures Professor Bruno Quesnel. The variations of this new therapeutic weapon are already numerous: bispecific antibodies, cell and gene therapies (CAR-T cell)…

“We will now have to succeed in combining the treatments as intelligently as possible”, notes Pierre Saintigny, oncologist at the Léon Bérard center in Lyon. “With immunotherapy, we have climbed a stage in the treatment of cancer, but there are still steps to climb for all the patients who do not benefit from it.“.

Researchers can rely on the ability of biotechnologies to develop new drugs that are ever more specific and less toxic.

Another pillar on which to rely: the development of artificial intelligence (AI), which already allows a better definition of the prognosis of cancer. Thanks to her, “we will be able to identify which patients can benefit from a short treatment”, assures Fabrice André. Advantage: therapeutic de-escalation for patients and lower costs for the community.

Breast cancer pioneered the use of AI, which should now benefit other cancers.

Circulating DNA for earlier diagnosis and better monitoring of treatment

Another hope lies in the ability to detect a tumor very early in the body. “We already do it in the United States by looking at DNA through a simple blood test, but there are still a lot of false positives”, notes Fabrice André.

Before the generalization of such a technique, prevention remains to this day the best way to avoid a large part of cancers.