Abstract
PURPOSE: The effects of biological subtypes within breast cancer on prognosis are influenced by age at diagnosis. We investigated the association of young age with locoregional recurrence (LRR) between patients with luminal subtypes versus those with nonluminal subtypes. MATERIALS AND METHODS: Medical records of 524 breast cancer patients with positive lymph nodes between 1999 and 2010 were reviewed retrospectively. All patients received curative surgery and adjuvant chemotherapy based on contemporary guidelines. Radiation was delivered for patients who underwent breast conserving surgery or those who had four or more positive lymph nodes after mastectomy. Adjuvant hormone therapy was administered to 413 patients with positive hormone receptors according to their menstrual status. RESULTS: During median follow-up of 84 months, the 10-year locoregional recurrence-free survival rate (LRRFS) was 84.3% for all patients. Patients < 40 years showed significantly worse 10-year LRRFS than those ≥ 40 years (73.2% vs. 89.0%, respectively; p=0.01). The negative effect of young age on LRRFS was only observed in luminal subtypes (69.7% for < 40 years vs. 90.8% for ≥ 40 years; p < 0.01). Multivariate analysis using luminal subtypes ≥ 40 years as a reference revealed luminal subtypes < 40 years were significantly associated with increased risk of LRR (hazard ratio, 2.33; p < 0.01). CONCLUSION: Young breast cancer patients with positive lymph nodes had a higher risk of LRR than those aged ≥ 40 years. This detrimental effect of young age on LRR was confined in luminal subtypes.