Prognosis according to the timing of recurrence in breast cancer

Clinically, breast cancer can be divided into 4 subtypes based on the presence of hormone receptors, human epidermal growth factor receptor 2 (HER2), and Ki-67. Because the pattern and time of recurrence vary according to the subtype, we evaluated whether there was a difference in overall survival (OS) among the subtypes according to the time and type of recurrence. A total of 2,730 patients who underwent breast cancer surgery were analyzed. Early and late recurrence were defined as recurrence within and after 5 years of diagnosis, respectively. Recurrence type was categorized as locoregional recurrence or systemic recurrence. Hormone receptor-positive tumors were significantly more frequent in the late recurrence group than in the early recurrence group (estrogen receptor positive, 47.8% [early] 78.7% [late]). However, there was no difference in the rate of HER2 overexpression (HER2+, 38.1% [early] 39.0% [late]). In subgroup analysis, early recurrence was a significant prognostic factor for OS in all subtypes. However, late recurrence was a significant prognostic factor for OS only in the luminal B subtype (hazard ratio of 4.30). In addition, the luminal B type had the highest proportion in late recurrence patients (63.2%). The luminal B subtype had a high rate of late recurrence, and late recurrence was a poor prognostic factor for OS only in this subgroup. Therefore, further targeted treatments for luminal B breast cancer are needed and patients with this subtype require close long-term surveillance.