RESUMO
Although 5fluorouracil (5FU)based chemotherapy is the major treatment for colorectal cancer, it has disadvantages such as systemic toxicity, lack of effectiveness and selectivity, and development of resistance. Capecitabine, a prodrug form of 5FU, was designed to overcome these drawbacks, to fulfill the need for more convenient therapy, and to improve safety, tolerability and intratumor drug concentration levels through a tumorspecific conversion to the active 5FU drug. The purpose of the present review is to provide a comprehensive comparison between 5FU therapy and capecitabine. In the current review, anticancer drug classification was discussed and the development of capecitabine from the original fluorinated analogue (5FU) to overcome its drawbacks was explained. Specifically, 5FU is compared with capecitabine therapy regarding various properties, including drug metabolism, cellular mechanism, effect on the apoptosis pathway and cell cycle phases, safety and tolerability. Moreover, three metabolizing enzymes required for the activation of capecitabine to 5FU were discussed. Capecitabine, as monotherapy or in combination with other chemotherapies, exhibited improved drug efficacy and survival. However, the changes that mediate the chemoresistance of capecitabine treatment were classified as intracellular, extracellular or cell surface factors, or cellphenotype state. Future studies should examine the efficacy of capecitabine combined with novel and safe drugs other than chemotherapeutic agents that play a role in the inhibition of tumor initiation, progression and metastasis.