Camrelizumab and apatinib combined with chemotherapy in perioperative effective therapy for advanced gastric carcinoma with peritoneal metastasis: a case report.

Background: Peritoneal metastases (PMs) are the most frequent metastatic pattern with a very poor prognosis in stage IV gastric cancer (GC). An effective therapeutic option has yet to be established. Combination therapy of anti-angiogenesis therapy, immunotherapy and chemotherapy was first used in advanced GC for perioperative treatment in this case. Case Description: A 39-year-old man was diagnosed with stage IV GC with PM (CY1, P1) and the patient had an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 1 and adequate organ function. After disease progression on the first-line chemotherapy of paclitaxel plus S-1, the patient received a transformational therapy of camrelizumab (immune checkpoint inhibitors) plus apatinib (anti-angiogenic agent) combined with chemotherapy leading to macroscopic disappearance of the peritoneal lesions, negative peritoneal cytology, and the absence of other distant metastases, rendering him suitable to accept a radical gastrectomy with D2 lymph node dissection. The postoperative histopathology showed a tumor regression rate of more than 90%. Later, the patient was admitted for adjuvant therapy of camrelizumab plus apatinib combined with chemotherapy and relapsed at around 8 months after surgery. Treatment was well tolerated with no significant adverse effects. Conclusions: Camrelizumab plus apatinib combined with chemotherapy as second-line treatment demonstrated feasible anti-tumor activity and manageable safety in this advanced GC patient with PM and provided an opportunity for radical resection, improving the objective response rate (ORR) and prolonging patient survival. The incorporation may overcome resistance to treatment with therapy alone and produce synergistic effects, indicating a promising treatment option in the clinic to GC with PM.