50P Early breast cancer in women aged 35 years or younger: A French population-based case control-matched analysis
Résumé
Background
There is a scarcity of data exploring prognostic factors in young patients with breast cancer (BC), and the independent negative impact of age by itself is still debated. We aimed to assess shared and intrinsic prognostic factors in a large cohort of patients aged 35 years or younger, compared to a control group aged from 36 to 50.
Methods
Patients ≤50 years old were retrospectively identified from a large cohort of 23 134 early BC patients who underwent primary surgery in 18 academic centers between 1990 and 2014. Multivariate Cox analysis aiming to identify factors associated with disease-free and overall survival (DFS and OS) were built for the total cohort, and then for the ≤35 years cohort only. To further assess the independent impact of age on DFS and OS, 1 to 3 case control analysis was performed by matching ≤35 and 36 to 50 according to histology, grade, tumor size, lymphovascular invasion (LVI), nodal status, endocrine receptors (ER), endocrine therapy (ET) and chemotherapy (CT).
Results
On 6 481 patients included, 556 were aged ≤35 years, and 5 925 from 36 to 50. Compared to the 36-50 group, age ≤35 was significantly associated with larger tumors, higher grade, ER negativity, macroscopic lymph node involvement, LVI, and higher rates of mastectomy and chemotherapy use. In multivariate analysis, age ≤35 was associated with worse DFS (HR 1.59, 95% CI 1.35-1.88; p<0.001), and OS (HR 1.32, 95% CI 1.06-1.64; p=0.014), as were high grade, large tumor size, LVI, macroscopic lymph node involvement, ER negativity, and absence of ET or CT. Adverse prognostic impact of age ≤35 was maintained in the case control-matched analysis for DFS (HR 1.56, 95%CI 1.28-1.91, p<0.001), and OS (HR 1.33, 95%CI 1.02-1.73, p=0.032). When considering patients ≤35 for multivariate analysis, only ER, tumor size, lymph node involvement and LVI remained statistically significantly associated with OS and DFS.
Conclusions
An age ≤35 years is associated with less favorable features at BC diagnosis, and more aggressive treatment strategies. Our results support the poor prognosis value of young age, which independently persisted when adjusting for other prognostic factors and treatments, as well as in the control-matched analysis.