Purpose: We sought to examine the role of pretreatment systemic immune-inflammation index (SII) in hormone receptor-negative, human epidermal growth factor receptor 2+ (HER2+) breast cancer patients.
Patients and methods: 155 HER2+ patients treated in our hospital from September 3, 2002, to September 21, 2012, were retrospectively enrolled. SII was established as neutrophil x platelet/lymphocyte counts. The median value of SII was used as cut-off value. We used the Kaplan-Meier method to evaluate the overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS). To comparatively evaluate the survival rates between patients from two groups, we used the log-rank test. For identifying independent factors of prognosis, we used the Cox regression model, applying multivariate statistics.
Results: Analyses show that HER2+ patients with high and low SII had median DFS of 15.1 and 31.5 months, respectively (P <0.001), while the median DMFS in HER2+ patients with high SII was 18.4 and in patients with low SII was 33.0 months (P =0.001), and the median OS were 54.5 and 71.1 months respectively in high and low SII patients, respectively (P =0.002). Multivariate analysis had revealed increased SII independently linked to poor DFS (HR =1.46, 95% CI: 1.01–2.11, P =0.045). The difference between SII and DMFS bore no statistical significance. (HR =1.40, 95% CI: 0.96–2.03, P =0.078), while high SII independently predicted short OS (HR =1.51, 95% CI: 1.02–2.25, P =0.038).
Conclusion: Our findings suggest that increased SII independently predicts poor survival for hormone receptor-negative, HER2+ breast cancer patients. Prospective studies are, however, required to confirm the role of SII in the prognosis of patients with HER2+ before clinical use.
Keywords: breast cancer, SII, HER2, inflammation