CDA and neoplasm: Capecitabine (CAP) is a class of oral anticancer drugs that are rapidly absorbed via the intestinal mucosa after oral administration, converted to inactive intermediate 5′-deoxy-5′fluorocytidine by carboxylesterase in the liver, transformed to 5′-deoxy-5′fluorouracil by the action of cytidine deaminase in the liver and tumor tissue, and finally catalyzed by thymidine phosphorylase in the tumor tissue to fluorouracil (5-FU) to perform antitumor effects [9].