Treatment of peritoneal metastases from small bowel adenocarcinoma

<b>Background/purpose:</b> Peritoneal metastases (PM) affect approximately one third of patients with metastatic small bowel adenocarcinoma (SBA). Treatment options are (1) systemic therapy ± palliative surgery and (2) cytoreductive surgery with intraperitoneal chemotherapy (CRS + IPC). Due to scarce evidence, PM from SBA represents a therapeutic challenge. This narrative review summarised and discussed the evidence that investigated available treatment options. <b>Methods:</b> Studies were discussed if they investigated first line systemic therapy for advanced SBA or CRS + IPC for PM from SBA. Extracted outcomes were objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), disease-free survival (DFS), overall survival (OS), and grade III–V toxicity/morbidity. <b>Results:</b> Eighteen studies (15 observational, 3 phase II) that investigated systemic therapy and six observational studies that investigated CRS + IPC were reviewed. In studies that investigated systemic therapy, ORR, DCR, median PFS, median OS, and grade III–V toxicity ranged from 6% to 50%, 50% to 90%, 3 to 11 months, 8 to 20 months, and 10% to 68%, respectively. Fluoropyrimidine–oxaliplatin revealed favourable survival outcomes compared to fluoropyrimidine–irinotecan, fluoropyrimidine–cisplatin, fluoropyrimidine monotherapy, and other regimens. In studies that investigated CRS + IPC, median DFS, median OS, and grade III–V morbidity ranged from 10 to 12 months, 16 to 47 months, and 12% to 35%, respectively. <b>Conclusion:</b> Based on available evidence, fluoropyrimidine–oxaliplatin should be regarded as optimal first line systemic treatment. In selected patients, CRS + IPC appears safe and may be more effective than systemic therapy as single treatment. Future studies should evaluate survival and morbidity of CRS + IPC in larger cohorts, as well as the value of chemotherapy with targeted agents in metastatic SBA with subgroup analysis for PM from SBA.