'FLARE' of tumor marker in advanced gastric cancer treated with first-line systemic therapy

Background: Transient tumor marker elevations caused by chemotherapy were defined as 'Flare' and have been demonstrated in some solid tumors. In clinical practice, we observed that some patients were accompanied by elevated tumor markers during treatment, but subsequent imaging proved that the treatment they received was effective. Objectives: We aimed to study the Flare and the prognosis in advanced gastric cancer. Design: This is an observational retrospective study. A total of 167 patients were enrolled in this study. Carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9 and CA125 values were obtained before the first, second, third, fourth, fifth and sixth cycles of treatment, respectively. Methods: Imaging for the first efficacy assessment was reviewed according to the Response Evaluation Criteria in Solid Tumors 1.1 (RECIST 1.1) criteria. Kaplan-Meier analyses and log-rank tests were performed for overall survival (OS) analyses. Univariate and multivariate Cox analyses were used to determine the prognostic factor for OS and progression-free survival (PFS). Results: 37.1% of patients were accompanied with at least one tumor marker Flare during the course of treatment. The median time to tumor marker peak was 24-30 days and the Flare duration lasted 49-53 days. Patients with tumor markers Flare had a worse OS. Flare may be associated with the use of 5-fluorouracil. Baseline CEA and CA125 levels were the independent prognostic factors for OS and baseline CA125 level was the independent prognostic factor for PFS. Conclusion: Initial elevation of tumor markers during treatment is not an indication of tumor progression. Patients with tumor markers 'Flare' may had a worse OS.