The main cancers, such as breast, lung and colon cancers do not exist in children. They mainly suffer from leukemia, bone cancer, brain cancer or kidney. But fortunately in a much rarer way! These diseases are not due either, like many in adults, to carcinogenic agents (tobacco, alcohol …), so we cannot prevent them. And these cancers are not usually hereditary. Only a very small part can be explained by a genetic abnormality transmitted.
The cause of pediatric cancers is most often unknown. These are embryonic tumors, so qualified because of the rapidity of their development, which mimics that of the cells of an embryo. A characteristic which makes them cancers very sensitive to chemotherapy, since this one is more effective on the cells with rapid renewal.
Cancers different from those of adults
These cancers are most often treated with chemotherapy. High doses that can be borne by children, sometimes with the help of an autograft in leukemia: chemotherapy eliminates all blood cells, then reconstituted by the transplant. In solid tumors, surgery and radiation therapy are used. Over the years, this has become more precise, which makes it possible to avoid irradiation of the healthy tissues around the tumor as much as possible.
All of these treatments lead to the cure of 80% of children and adolescents. Good results certainly, but 20 to 40% of children cured of their cancer suffer from complications later. The current challenge is therefore to improve the quality of healing for these young people.
Towards increasingly targeted treatments
Allow children to benefit from discoveries made in adults. That is to say, orient the treatments according to the biology of the tumor (targeted treatments) or boost their immune system so that they can defend themselves better (immunotherapy).
In some leukaemias and in certain childhood brain tumors, the same abnormalities are found as in melanomas (skin tumors in adults). A treatment targeting this abnormality (BRAF inhibitor) is available in adults. The idea is to offer them to children with recidivism. Twelve drugs are thus in the early evaluation phase. The HER 2 mutation, found in certain breast cancers, has also been identified in certain rare pediatric cancers (gliomas). Twelve drugs are thus in the early evaluation phase. And concerning immunotherapy, the first studies are encouraging.
As these are rare diseases, it is necessary to group children from all over the world who suffer from the same cancers to set up trials in order to find out more quickly what works. A European consortium (ITCC: Innovative therapies for children with cancer europeen consortium), in which doctors, parents and representatives of laboratories sit around a table, are currently working in this direction. And measures are underway to encourage laboratories to undertake specific tests in children. This includes the organization of a long-term follow-up. No question of seeing parents cross the Atlantic to have a new drug in experimentation. We can do this in Europe and France is a leader in this field!
Thanks to Dr Gilles Vassal, oncologist pediatrician in Gustave-Roussy (Villejuif).
