Complete remission of alpha-fetoprotein-producing gastric cancer by combined tislelizumab-apatinib treatment of a patient with proficient mismatch repair: a case report

BACKGROUND: Alpha‑fetoprotein-producing gastric cancer (AFPGC) is a rare type of gastric cancer with a high rate of metastasis and poor prognosis. Despite substantial progress in the treatment of many solid tumors, there are no reports of the safety and effectiveness of immune checkpoint inhibitors in combination with antiangiogenesis agents for AFPGC patients who have proficient mismatch repair. CASE PRESENTATION: We describe a 69-year-old man who was diagnosed with metastatic AFPGC. After progression to chemotherapy resistance, tislelizumab combined with apatinib was administered, although the patient’s gastroscopic pathology showed proficient mismatch repair. After three cycles of therapy, partial remission (reduced by 56%) was obtained, and the quality of life improved significantly. Surprisingly, after more than 1 year of continuous application of the combination treatment regimen, both the primary and metastatic tumors in this patient eventually disappeared, which obtained complete remission without surgery. The patient has had a progression-free survival of more than 24 months and is still continuing to benefit. CONCLUSIONS: This case is the first example of effective treatment of AFPGC with tislelizumab combined with apatinib. The outcomes of this case suggest a highly effective and tolerable therapeutic strategy for microsatellite-stabilized AFPGC.