Efficacy of Capecitabine and Temozolomide in Small Bowel (Midgut) Neuroendocrine Tumors

SIMPLE SUMMARY: The capecitabine/temozolomide (CAPTEM) regimen has proven activity in pancreatic neuroendocrine tumors (NETs); however, data are limited in NETs of the small bowel. To observe whether this regimen has activity in this patient population, we conducted a retrospective study of all patients with small bowel NETs treated with this regimen at our institution. We found that response rates were poor among patients with low-intermediate grade tumors but higher among patients with high-grade disease. Our findings suggest that the CAPTEM regimen should be reserved for patients with higher-grade small bowel NETs. ABSTRACT: The capecitabine/temozolomide regimen has significant activity in pancreatic NETs; however, data are limited in NETs of the small bowel (midgut). A retrospective study of all patients with metastatic midgut NETs seen at Moffitt Cancer Center between January 2008 and June 2019 treated with CAPTEM was conducted. 32 patients with proven or suspected well-differentiated primary small bowel NETs (excluding duodenum) were identified. 6 patients were found to have a radiographic response (19%), 5 of whom had high-grade disease. Only one patient among 23 with low/intermediate-grade disease responded (4%), whereas the response rate for patients with high-grade disease was 56%. Among patients with low/intermediate-grade disease, 44% discontinued due to poor tolerability. The CAPTEM regimen appears to have an activity in patients with high-grade small bowel NETs and is largely inactive in patients with low/intermediate-grade tumors.