Clinical significance of changes in systemic inflammatory markers and carcinoembryonic antigen levels in predicting metastatic colorectal cancer prognosis and chemotherapy response

Aim Metastatic colorectal cancer (mCRC) is associated with poor prognosis, and biomarkers are required for predicting survival and chemotherapy response. This study aimed to evaluate the significance of changes in systemic inflammatory markers and carcinoembryonic antigen (CEA) levels in predicting mCRC prognosis and chemotherapy response. Methods In this retrospective study, 503 patients who received first‐line palliative chemotherapy for mCRC between 2008 and 2014 at a tertiary hospital in Korea were evaluated. Changes in neutrophil‐to‐lymphocyte ratio (NLR) and modified Glasgow prognostic score (mGPS) were divided into low‐to‐low, high‐to‐low, low‐to‐high and high‐to‐high groups. The CEA response was defined as CEA‐complete response (CEA normalization), CEA‐partial response (≥50% decrease in CEA levels), CEA‐progressive disease (≥50% increase in CEA levels) and CEA‐stable disease. Overall survival (OS) and progression‐free survival (PFS) were evaluated according to NLR, mGPS and CEA levels. Results High prechemotherapy NLR, mGPS and CEA levels independently predicted poor survival and chemotherapy response. Continuously high NLR or change to high NLR was also associated with poor OS and PFS; however, continuously low NLR or reduced NLR showed good prognosis. CEA response was also an independent prognostic marker for OS and PFS. High NLR and mGPS were correlated with elevated CEA levels. Conclusion Inflammatory marker levels were significantly associated with CEA levels. The prechemotherapy levels of systemic inflammatory markers and CEA were associated with OS or PFS. The change patterns in NLR and CEA levels can be utilized as prognostic and predictive markers for chemotherapy response.