"Genetic" breast cancer is no more lethal than the others

Published on 05/11/2024 01:48

Women under 40 years of age carrying the BRCA1 and BRCA2 genes responsible for breast cancer do not have a higher risk of mortality than those who are not predisposed to the disease, that is to say non-carriers of the genes.

When he arrives in a woman's life without warning, breast cancer upsets everything in her path. Some discover that they carry the BRCA1 or BRCA2 gene that exposes them to breast and ovarian cancers. As a reminder, the risk of developing breast cancer before the age of 70 with BRCA1 is 51 to 75%. With BRCA2, it is 33 to 55%.

A recent British study (POSH) published in The Lancet Oncology *, however, has shown that the risk of death in people with breast cancer with genetic predisposition is not higher than those who do not have this gene.

12% of women tested carrying BRCA1 or BRCA2 genes

To reach this conclusion, tests were carried out on 2733 patients under 40 in more than 100 hospitals in Britain. The women who participated in the experiment were all diagnosed with breast cancer between 2000 and 2008, and followed for about eight years. Of these, 12% were carriers of BRCA1 or BRCA2, but almost none were aware that she was a carrier at the time of diagnosis. The patients were treated with the same reference chemotherapy treatment of that time: antracyclines or taxanes.

Professor Diana Eccles, lead author of the study, said: "In terms of overall survival or relapse-free survival, there is no difference between BRCA1 or 2 mutation carriers and other patients. ". Reassuring results for these patients who contradict the results of previous studies on the same subject.

However, the danger of breast cancer in these subjects, called "young", remains higher than in postmenopausal women . 3% of women studied during the study died two years after their diagnosis, 16% after 5 years and 30% after 10 years.

Not so urgent preventive mastectomies

The risk of cancer recurrence (on the same breast or on the other) is high in women, but even more so in women carrying genes. Preventive removal of one or more breasts is thus often recommended.

The POSH study could however change the situation regarding this practice. "Our study confirms that the priority for a woman recently diagnosed with breast cancer is to receive the best treatment, and double mastectomy is not part of routine treatment, and in our cohort nearly one in five women carriers of BRCA1 had a second cancer during the follow-up years, so it is still necessary to discuss the double mastectomy, but some women may choose to postpone the operation until they have recovered well, physically and psychologically, from the treatment. their cancer, "explained Pr Eccles to our colleagues at Le Figaro.

These findings are not limited to women who have developed cancer at a premature age. "Elderly women have a better prognosis for breast cancer and there are proportionally fewer carriers of predisposing genetic mutations," says Pr Diana Eccles.

* www.thelancet.com/journals/lanonc/article/PIIS1470-2045(17)30891-4/fulltext?code=lancet-site