Adjuvant Chemotherapy Guidance in Young Breast Cancer Patients With Luminal Subtypes and Stage pT1N0

Background This study evaluated whether young breast cancer patients (≤ 40 y of age) with luminal subtypes and stage pT1N0 can benefit from chemotherapy (CHT). Materials and methods This study included 688 patients aged ≤ 40 y with luminal subtypes and stage pT1N0 breast cancer. The overall survival and disease-free survival (DFS) rates in the whole cohort and subgroups were compared between patients receiving CHT followed by endocrinotherapy (ET) (CHT→ET group) and those receiving only ET (ET-alone group). Results Univariate analysis identified that the tumors in the CHT→ET group were more aggressive than those in the ET-alone group. However, the overall survival and DFS rates did not differ significantly between the CHT→ET and ET-alone groups (P = 0.416 and 0.21, respectively), implying that a subgroup of patients could benefit from CHT. Subgroup analysis of DFS rates revealed that patients with human epidermal growth factor receptor 2 overexpression (P = 0.042), histological classification grade 3 (P = 0.030), progesterone receptor ≤ 20% (P = 0.033), and clinical stage T1c (P = 0.038) could benefit from CHT. Further analysis showed that these four risk factors combined predicted whether the patient could benefit from CHT. Conclusions Young patients with hormone receptor–positive and stage pT1N0 breast cancer may benefit from CHT only if they exhibit at least two of the following risk factors: progesterone receptor ≤ 20%, human epidermal growth factor receptor 2 overexpression, histological grading 3, or clinical stage T1c.