Prognostic Value of Chemotherapy-Induced Neutropenia at the First Cycle in Invasive Breast Cancer

Chemotherapy-induced neutropenia (CIN) was the most apparent side effects of bone marrow suppression with adjuvant chemotherapy. Recently, several studies revealed that CIN may predict better outcomes. However, the researches upon breast cancer were still indefinite. We reviewed the female patients with pathologically diagnosed invasive breast cancer at the First Affiliated Hospital of Wenzhou Medical University, between Jan 2008 and Dec 2010. The lowest neutrophil counts in the second week after the first cycle of chemotherapy were collected. Clinicopathological characteristics and survival rates were compared and analyzed between the CIN group and non-CIN group. The median follow-up time was 62 months. The differences of over-all survival and local recurrence-free survival between the 2 groups were nonsense (P = 0.938, P = 0.695, respectively). But the disease-free survival and distant metastasis-free survival of the CIN group were statically significantly better (HR = 0.391, P = 0.009, and HR = 0.315, P = 0.005, respectively). The bone metastasis-free survival may be responsible for the differences (HR = 0.469, P = 0.005). Subgroup analyses showed the CIN may predict lower bone metastases rates with ER positive status, premenopause or younger age (≤ 40) (P = 0.002, P = 0.004, and P = 0.0001, respectively). Cox analysis showed younger ages, N staging, and the presence of CIN were associated with bone metastasis-free survival independently adjusting to peritumoral vascular invasion (P < 0.05). CIN may predict a decreased recurrence risk of breast cancer, especially bone metastases.