Combining anti-PD-1 antibodies with surufatinib for gastrointestinal neuroendocrine carcinoma: Two cases report and review of literature

BACKGROUND Gastrointestinal neuroendocrine carcinoma (GI NEC) has a low incidence rate and poor prognosis. Most patients already have metastatic disease when they are diagnosed. Platinum chemotherapy is the main means of treating metastatic GI NECs. There is a lack of effective treatment methods after chemotherapy failure. Therefore, Therefore, selecting appropriate posterior-line treatment programs to improve the prognosis of patients is urgently needed. CASE SUMMARY A 64-year-old female was diagnosed with stage IV NEC of the rectum due to abdominal pain and rectal bleeding. After multiline chemotherapy, the condition progressed, and the patient was treated with a combination of camrelizumab and surufatinib. The efficacy evaluation revealed partial remission (PR) and stable conditions, with the expression of the tumor marker neuron-specific enolase (NSE) returning to normal. The adverse reactions were controllable, and the overall condition was good, with weight gain achieved in the past four years. Another 51-year-old female experienced recurrence and metastasis of a duodenal NEC after surgery. After multiline chemotherapy, she received sintilimab combined with surufatinib. The curative effect fluctuated between PR and stability. During treatment, she recovered from immune-related diabetes and later died due to deterioration of her condition. During the treatment, the patient’s NSE level returned to normal. CONCLUSION The combination of antiangiogenic targeted drugs and immunotherapy provides a new therapeutic approach for the treatment of metastatic GI-NECs.