First-line application of apatinib combined with S-1 based on peripheral circulating tumor cell screening to treat advanced gastric adenocarcinoma: a case report

Apatinib mesylate, a small-molecule tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptor-2 (VEGFR-2), has been recommended as a third-line class A agent for patients with advanced gastric adenocarcinoma in China since April 2018. Thus far, there is no case report on the combined use of apatinib and S-1 as the first-line treatment option for metastatic gastric cancer (GC) patients based on peripheral circulating tumor cell (pCTC) monitoring. We present a unique case in which liver metastases originating from GC gradually shrank and disappeared in the presence of pCTC-positive disease after treatment with apatinib for 17 months. More surprisingly, the pCTCs became negative after the addition of S-1 halfway through treatment. A 71-year-old Chinese man who underwent gastroscopic biopsy and laparoscopy was diagnosed with gastric adenocarcinoma with multiple liver metastases. The pathological stage was T4NxM1. The patient obtained clinical benefit from first-line apatinib within 4 weeks. After developing grade 2 hand-foot syndrome, the patient began to take S-1 alone. When the condition was significantly relieved, the elderly patient continued to take apatinib combined with S-1 and achieved satisfactory therapeutic results. Many studies suggest that the prognosis of this type of GC is grim. However, apatinib increased the overall survival (OS) duration of the patient to 34 months. We hypothesize that combining apatinib with S-1 as a first-line therapeutic option for pCTC-positive advanced GC is feasible.