Serum creatinine and cystatin C-based index is a prognostic factor in patients with nonmetastatic breast cancer after surgery.

BACKGROUND

Sarcopenia is an important prognostic factor of breast cancer (BC). The serum creatinine/cystatin C ratio (CCR) and the serum creatinine × cystatin C-based glomerular filtration rate (SCr × eGFRcys) index are novel screening tools for sarcopenia; but to date, has not been studied in Chinese patients with BC. We aimed to explore and investigate their prognostic values for overall survival (OS) and recurrence-free survival (RFS) in patients with BC undergoing surgery.

METHODS

This cohort study Chinese women who were diagnosed with primary nonmetastatic BC (T1-4N0-3M0) and underwent surgery at our Hospital between January 2011 and December 2017. Preoperative laboratory data, clinicopathological feature and postoperative adjuvant treatment details were collected from medical records. Patients were divided into SCr × eGFRcys index or CCR quartiles. Kaplan-Meier survival was performed to estimate rate difference of outcomes of interest for each quartile of these two indices, and cox regression analyses were used examine their associations, respectively. The cutoff value of the SCr × eGFRcys index was determined using receiver operating characteristic curves.

RESULTS

Among 697 nonmetastatic BC women included in total, 6.6 % (46/697) of death and 60 (8.61 %) recurrence occurred after a median follow-up of 76 months (interquartile range, 67-88 months). Kaplan-Meier analysis showed significant differences in OS rates for SCr × eGFRcys index quartiles (log-rank P = 0.031), but not for CCR quartiles (log-rank P = 0.27). The higher SCr × eGFRcys index quartiles was an independent prognostic factor for OS in multivariate analysis, with a decreased mortality risk (hazard ratio [HR], 0.29; 95 % confidence interval, 0.09-0.92 when the 4th SI quartile vs. the lowest) after adjusting for preoperative clinicopathological features, but the significant association was not found with CCR quartiles. Furthermore, subgroup analysis revealed that the prognostic ability of SCr × eGFRcys index was only held in patients with low prognostic nutritional index, early TNM stage, normal-weight, and those without chemoradiotherapy.

CONCLUSIONS

Higher SCr × eGFRcys index is associated with a favourable long-term prognosis of BC, and SCr × eGFRcys index may be considered as pragmatic biomarker for clinicians when managing patients with BC in daily clinical practice.