Serum biomarkers for predicting overall survival and early mortality in older patients with metastatic solid tumors

We aimed to explore serum biomarkers for predicting survival of older patients with metastatic solid tumors who received first line palliative chemotherapy.

Serum samples were prospectively collected before first-line chemotherapy at 11 academic centers in Korea. All patients were participants in a prospective cohort study of older patients with metastatic solid tumors. Serum levels of C-reactive protein (CRP), CXCL10, SIRT1, VEGF-A, activin A, C-terminal telopeptide of type I collagen (CTx), total 25-hydroxyvitamin D were measured by ELISA and interleukin-6 (IL-6), myostatin, irisin, FGF-19, FGF-21, FGF-23 by Luminex multiplex assay. Overall survival (OS) was determined.

Serum samples from 138 patients (median age: 75 years, range: 70-92 years) were collected from February 2014 to December 2016. During a median follow up time of 13.8 months, 73 (52.9%) patients died. Among 13 serum markers, CRP (log-rank, P = 0.009), activin A (P = 0.007), and myostatin (P = 0.047) were significantly correlated with OS in univariate analyses. Activin A (hazard ratio [HR] 2.22, 95% confidence interval [CI] 1.32-3.72; P = 0.003) and myostatin (HR 3.02, 95% CI 1.39-6.57; P = 0.005) were significantly associated with OS after adjustment for other clinical factors. In predicting early (6-month) mortality, two inflammatory markers, IL-6 and CRP, were included in the decision-tree model.

In older patients with cancer, high serum concentrations of activin A and myostatin were predictive of poor OS. IL-6 and CRP might be useful to select older patients at risk of early mortality. These markers could be incorporated into predictive tools for clinical decision-making and warrant further investigation.