Salvage camrelizumab for an intractable NK/T cell lymphoma patient with two instances of intestinal perforation: a case report and literature review.

BACKGROUND: The prognosis of natural killer/T cell lymphoma (NKTCL) with multifocal small intestine involvement complicated by intestinal perforation is extremely poor. There is no evidence-based treatment strategy for this intractable condition. CASE PRESENTATION: A 30-year-old male was admitted to our hospital in April 2017 and presented with recurrent fever for three months and multiple painless subcutaneous nodules in the abdominal wall. An excision biopsy of the subcutaneous nodules in the abdominal wall revealed NKTCL. The patient was diagnosed with stage IVB NKTCL with skin and multifocal small intestinal involvement according to the imaging results. The first intestinal perforation occurred due to tumor infiltration before the initial treatment. The second intestinal perforation occurred after receiving two cycles of chemotherapy with a modified SMILE regimen. The histone deacetylase inhibitor (HDACi) chidamide was administered as a single-agent therapy after recovery from the second intestinal perforation. Complete remission was achieved. Unfortunately, five months later, the patient was confirmed to have relapsed and received the salvage chemotherapy. The patient suffered from disease progression again after the fourth cycle of chemotherapy. At this point, from May 29, 2018, the patient started to receive injections of the anti-programmed death 1 (PD-1) antibody camrelizumab as a salvage treatment. Two months after the initial anti-PD-1 antibody camrelizumab injection, the response was partial remission. Disease progression was confirmed in March 2021, with a progression-free survival time of 34 months. CONCLUSIONS: NKTCL patients with multifocal small intestine involvement have a high risk of intestinal perforation. The possible etiologies of bowel perforation include tumor infiltration, tumor necrosis in response to therapy, and acute inflammation. The anti-PD-1 antibody camrelizumab may be a new candidate agent for treating this type of intractable NKTCL. Further observations are necessary to identify the efficacy and safety of new agents in the future.