Table 2.

Patients' characteristics according to recurrence status

ER, estrogen receptor; PR, progesterone receptor. ^a)Recurrence-free survival rate, ^b)Kaplan-Meier statistical method, compared using the log-rank test, ^c)The tumor grade was determined according to the Scarff-Bloom-Richardson classification modified by Elston and Ellis, ^d)Luminal A (ER⁺ and/or PR⁺, HER2^-, and Ki-67 index<15%), luminal B ([ER⁺ and/or PR⁺, HER-, and Ki-67 index≥15%] or [ER⁺ and/or PR⁺, and HER2⁺]), HER2 only (ER^-, PR^-, and HER2⁺), triple-negative (ER^-, PR^-, and HER2^-), ^e)The effect of tamoxifen on breast cancer recurrence was compared among patients with hormone receptor positive breast cancer, ^f)The effect of anti-HER2 therapy, including trastuzumab (Herceptin) and lapatinb (Tykerb), on breast cancer recurrence was compared among patients with HER2⁺ breast cancer.