Survival improvement in hormone-responsive young breast cancer patients with endocrine therapy

We investigated the oncologic outcomes by intrinsic subtype and age in young breast cancer patients and whether survival differences were related to treatment changes over time.

A retrospective analysis was performed on 9633 invasive breast cancer patients treated at Asan Medical Center from January 1989 to December 2008. We also enrolled a matched cohort adjusting for tumor size, lymph node metastasis, subtypes, and tumor grade. Patients aged <35 years were included in the younger group (n = 602) and those aged ≥35 years were included in the older group (n = 3009).

The younger patients showed a significantly higher T stage, a more frequent axillary node presentation, higher histologic grade, and higher incidence of triple-negative subtype tumors than older patients and also received more chemotherapy and were less likely to undergo hormone therapy. The younger patients with hormone receptor (HR)-positive tumors showed significantly poorer disease-free survival (DFS), loco-regional recurrence-free survival, distant metastasis-free survival, and breast cancer-specific survival outcomes than older patients. Younger patients with HR-positive and human epidermal growth factor receptor 2 (HER2)-negative tumor subtypes had a significantly improved DFS over time (p = 0.032). Within the HR-positive/Her2-negative subtype, more women received gonadotropin-releasing hormone agonist and tamoxifen treatment from 2003 to 2008 compared with 1989 to 2002 (p = 0.001 and p = 0.075, respectively).

HR-positive young breast cancer patients have a poorer survival compared with older patients, even with more frequent chemotherapy, but more recent use of tamoxifen and ovarian suppression might improve this outcome in these patients.