Between 2% and 5% of breast cancers are of genetic origin. And about 120,000 women could carry mutations predisposing them to breast and / or ovarian cancer. While these gene abnormalities are becoming better known, the question of extending testing to all women seems legitimate. However, many obstacles, scientific and ethical, persist.
How to calculate your risk of breast cancer? And above all, is it possible to evaluate it through a test? Certainly, being a carrier of BRCA1 or BRCA2 mutations is an important clue. But since 50% of pregnant women do not have a family history of breast cancer, "some international colleagues want the tests to be extended to all women over 30," says Dominique Stoppa-Lyonnet , head of the genetic service at the Institut Curie.
For her part, she believes that it is "desirable to broaden the indications reasonably to all women with triple negative breast cancer, to all those with breast cancer before age 40, or even to certain highly progressive breast cancers. ". But not to all unaffected women, without any other risk factor. "I advocate a progressive and reasoned evolution," she says. With "quality genetic tests whose clinical utility has been demonstrated, which would be accessible to all, with a notion of territorial access equity".
Classify variants, estimate risk modifying factors
"The expansion of the tests is only valid if the clinical utility of the test has been demonstrated," insists Dr. Stoppa-Lyonnet. Thus, according to her, "it would first be necessary to classify all the variants of genetic mutations". Indeed, the mutations are not all identical. Some are pathogenic, others are neutral or of unknown significance. But we must wait to know them well to extend the test to all women.
Moreover, "it will also be necessary to identify all risk-modifying (genetic) factors so as not to overestimate the tumor risks of this or that genetic mutation. Even though other factors come into play. Clearly, one should be sure of being able to read the test without error of interpretation.