Metronomic capecitabine in gastroenteropancreatic neuroendrocrine tumors: a suitable regimen and review of the literature.

Background: We present a retrospective analysis of metronomic capecitabine in metastatic gastroenteropancreatic neuroendrocrine tumors (GEP-NETs). A review of the literature is also presented.

Methods: From January 2007 to December 2013, ten patients with metastatic GEP-NETs (four pancreatic and six ileal) who progressed after treatment with somatostatin analogs and other cytotoxic agents received oral capecitabine 1,500 mg/day continuously. The median patient age was 68 (range 29-82) years. The median treatment duration was 8 months.

Results: Five (50%) patients achieved a partial radiographic response, four (40%) showed stable disease, and one (10%) progressed. Median overall survival was 56 months. Three of the four pancreatic patients achieved a partial radiographic response that lasted for a median of 15.5 months; overall survival and progression-free survival in this subgroup was 58 and 6 months, respectively.

Conclusion: Data in the literature show that capecitabine has only occasionally been used as a single agent, with increased toxicity. Only one study using single-agent capecitabine reported a progression-free survival of 9.9 months and overall survival of 36.5 months, without an objective response or major toxicity. In our experience, metronomic capecitabine was well tolerated, although minor side effects may have been underestimated due to the retrospective nature of our study. This regimen also seems to be feasible in elderly people. Although high response rates and prolonged response duration indicate the potential efficacy of this treatment, our results should be interpreted cautiously because of the small number of patients involved. Capecitabine was most effective in the pancreatic subgroup, which would seem to be more sensitive to chemotherapy.