Abstract P6-05-22: Young-onset breast cancer exhibits a more aggressive tumor biology

Abstract

Abstract Objective: Previous studies demonstrated poorer survival in patients with young-onset breast cancer. Therefore, we investigated the distinguishing molecular characteristics associated with young onset breast cancer. Material and Methods: Between September and February 2013, 506 patients with breast cancer, who underwent surgery at our institution, were retrospectively analyzed tailored by age ≤40 (n = 94; 18.6%) and >40 to determine clinicopathological and biological differences. Therefore, molecular subtypes were determined by immunohistochemistry for ER, PR, Ki67, and HER2-neu. Results: The median age was 50 (27-87). Patients aged ≤40 presented with more advanced disease (stage III/IV; 34% for ≤40 vs 20% for >40, p = 0.003). Among patients, who underwent surgery as initial treatment (n = 411), patients ≤40 were more likely to have or tumors with invasive ductal carcinoma type (p = 0.049), or tumors >20 mm (p = 0.033), or axillary positivity (p = 0.003), or with multifocality/multicentricity (p<0.001), or with high nuclear grade (p = 0.019), or with histological grade (p = 0.023), or lymphovascular invasion (p = <0.001), higher Ki-67 expression (%15≤) rates (p = 0.014), or lower luminal A rates (luminal-A vs other; p = 0.04) compared with patients aged >40. Furthermore, logistic regression analyses revealed presence of multifocality/multicentricity (OR:2.6; 95% CI: 1.4-4.5; p = 0.001), lymphovascular invasion (OR:2.1; 95% CI: 1.2-3.6; p = 0.008), and molecular subtype other than luminal A (OR:2.4; 95% CI: 1.1-5.1; p<0.001) were significant features that were associated with breast cancer aged ≤40. Conclusion: Our results suggest that tumors of patients with younger age exhibit a more aggressive biology compared to patients older than 40 as shown by molecular subtype analyses that could result in poor prognosis. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-05-22.