Breast cancer in young women: do BRCA1 or BRCA2 mutations matter?
Menée au Royaume-Uni auprès de 2 733 patientes atteintes d'un cancer invasif du sein diagnostiqué avant l'âge de 40 ans, cette étude de cohorte prospective évalue l'association entre la présence d'une mutation constitutionnelle d'un gène BRCA1 ou BRCA2 et la survie globale (durée médiane de suivi : 8,2 ans ; 678 décès par cancer du sein)
Young women with breast cancer have always caught the attention of both clinicians and researchers, despite this group being a rarity. Several factors distinguish the biology of both breast cancer in young patients and the patients themselves from that of tumours and patients who are diagnosed later in life. Additionally, the cancers might be associated with a previous pregnancy or have a pathogenesis that is based on a genetic predisposition; some data even imply that both cancers associated with a previous pregnancy and a genetic predisposition to cancer might be directly connected.
The POSH prospective cohort study by Ellen R Copson and colleagues, published in The Lancet Oncology has contributed to the understanding of this patient population after recruiting nearly 3000 patients diagnosed with breast cancer when younger than 40 years, and capturing comprehensive data about patient, tumour, and treatment characteristics, along with extensive follow-up data.
Copson and colleagues reported that patients with a BRCA1 or BRCA2 mutation had a similar prognosis as patients without these mutations: in 2733 women included in the analysis, overall survival at 2 years was 97·0% (95% CI 94·5–98·4) for BRCA mutation carriers versus 96·6% (95·8–97·3) for non-carriers (hazard ratio [HR] 0·96 [95% CI 0·76–1·22]; p=0·76). Similar results were seen at 5 years and 10 years. Additionally, in 558 patients with triple-negative breast cancer, those who had a BRCA mutation had better overall survival than did non-carriers at 2 years (95% [95% CI 89–98] vs 91% [88–94]; HR 0·59 [95% CI 0·35–0·99]; p=0·047), although there were no between-group differences at 5 years or 10 years.2
Importantly, prognosis in the POSH study meant survival after routine treatment for breast cancer. Among other factors, young age is regarded as an indication for treatment with chemotherapy, because prognosis is generally considered less favourable in younger and untreated patients than in patients diagnosed at an older age. (...)
The Lancet Oncology , commentaire en libre accès, 2017