The efficacy of oxaliplatin, surufatinib, and camrelizumab on neuroendocrine carcinoma: a case report and literature review.

Background: Extra-pulmonary neuroendocrine carcinomas (EP-NECs) are rare, accounting for ~1/100,000 of NECs, aggressive neoplasms and poor prognosis. Sometimes, a non-neuroendocrine component is also accompanying these EP-NECs. Curative surgery is suggested for early stage patients while system chemotherapy and locoregional radiotherapy are considered for advanced inoperable disease. Nonetheless, there was lack of standard second-line treatment strategy. Herein, we report a case of NEC involving a large cell neuroendocrine carcinoma (LCNEC) and adenocarcinoma of the gallbladder treated with a surufatinib-containing regimen in the second-line treatment setting and establish the efficacy of this regimen in the treatment of EP-NECs. Case Description: A 58-year-old male presented with symptoms such as distension in the upper right abdomen and a palpable mass. The abdominal magnetic resonance imaging (MRI) scan showed a giant soft tissue mass in the left lobe of the liver, and liver biopsy suggested LCNEC with a non-neuroendocrine (NNE) component. Based on the available literature, a first-line therapy of oxaliplatin + gemcitabine + camrelizumab + apatinib was started initially; however, there was rapid tumor progression. Thus, a second line of treatment was started, where apatinib was replaced with surufatinib, which was given along with oxaliplatin and camrelizumab and continued for seven complete cycles. The patient was re-examined with MRI, which showed a significant decrease in tumor size. And a partial response was achieved. Main adverse events included hand and foot numbness, hypertension, proteinuria, hematuria, and hyperthyroidism. The patient underwent surgery after the second line of treatment and the post-operative pathology report revealed the presence of LCNEC and adenocarcinoma of the gallbladder. Two months later, re-examination result showed no tumor recurrence. Conclusions: As yet, the criteria strategy for unresectable EP-NECs to improve survival outcomes is scarce. EP-NECs are badly in need of effective second-line therapy to carry out survival benefits after resistance to first-line regimen. The case report demonstrated that a surufatinib-containing regimen including oxaliplatin and camrelizumab could be an effective treatment strategy for the second-line treatment of EP-NECs. Furthermore, this strategy is well tolerated and treatment-related toxicity are manageable. More clinical trials are warranted to further confirm the efficacy.