Safety of chronic low-dose capecitabine as maintenance therapy in gastrointestinal cancers.

BACKGROUND: Maintenance chemotherapy is not routinely used in gastrointestinal (GI) cancers. Capecitabine is an oral formulation that is enzymatically converted to 5-fluorouracil preferentially in tumor tissue. We hypothesize that capecitabine could be used as a long-term maintenance therapy to improve outcomes in patients with high-risk GI cancers following standard chemotherapy regimens.
METHODS: We conducted a retrospective study to assess the toxicity of maintenance capecitabine in 28 patients with a variety of advanced GI malignancies. Capecitabine 1,000 mg twice daily without interruption was used for the first 11 patients. The dose was reduced to 1,000 mg twice daily 5 days per week in 8 patients who developed hand-foot syndrome. The remaining patients began treatment on the same abbreviated schedule. All documented clinical adverse events were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (v3.0, 2003).
RESULTS: Main toxicities were grade 1/2 fatigue and hand-foot syndrome. Only one grade 3 toxicity was observed and no grade 4 toxicities were seen. We also observed a significant increase in red blood cell mean corpuscular volume in participants, which may have potential use as a biomarker to monitor therapeutic response.
CONCLUSIONS: Fixed therapeutic doses of oral capecitabine 1,000 mg twice daily, 5 days on, 2 days off, can be administered chronically with a high level of safety and should be explored in larger prospective studies to demonstrate efficacy in GI malignancies, especially pancreatic and metastatic colorectal cancers.