Breast Cancer in Young Women: Is It Different? A Single-Center Retrospective Cohort Study

Introduction: Breast cancer (BC) is one of the commonest cancers among women worldwide. Differences regarding tumor biology, presentation, genetics, and molecular subtypes may contribute to the relatively poorer prognosis among younger women. Limited information exists regarding pathologic characteristics and long-term outcomes among this group. Methods: This retrospective cohort study included 695 BC patients diagnosed over a 10-year period and investigated the clinicopathological characteristics and long-term disease outcomes among patients diagnosed at age less than or equal to 40 years compared with older ones. Cox regression analysis was performed, and Kaplan-Meier curves were generated to assess overall survival (OS). Results: Compared with the younger patients (⩽40 years) estrogen receptor (ER) and progesterone receptor (PR) expression was mainly positive in older patients (>40 years) (76.2% vs 61.3% and 64.2% vs 49.6%, respectively). The most common molecular subtype in both age groups was luminal B (44.1% in older and 40.3% in younger). A clinical complete remission after neoadjuvant therapy was observed more frequently in older patients (76.7%; N = 442) in comparison with the younger patients (66.4%; N = 79) (P =.018). Recurrence and disease progression were significantly more likely to occur among younger patients accounting for 12.6% and 29.4% of the cases, compared with 6.3% and 18.2% in older patients (P =.016 and P =.006, respectively). The overall mortality was 132 (19%) of 695, with 88% cancer-related deaths. Estrogen receptor and PR expression (P ⩽.001 and P =.003, respectively), molecular subtype (P =.002), tumor grade (P =.002), and N stage (P =.038) were the variables that were found to be significantly influenced by age. The OS was not statistically different among 2 age groups, but younger patients with luminal A molecular subtype showed significantly poor outcome (P =.019). Conclusion: Overall survival in women diagnosed with BC at age less than or equal to 40 years is not significantly worse than older patients. However, among patients with luminal A subtype, younger women had relatively poor survival. Further research is needed to understand this age-based disparity in outcomes.