Adjuvant therapy in colorectal cancer.

While uncontrolled and retrospective studies suggest a treatment benefit for radiotherapy or chemotherapy when administered as adjuvant before or after surgical resection with a curative aim for colon cancer, prospective randomized clinicals trials failed to show any advantage and do not to date confirm the efficiency of the proposed adjuvant therapy. For rectal cancer, preoperative irradiation administered at the dose of 34.5 Gy and postoperative radiotherapy administered at the dose of 46 to 53 Gy markedly decreased the local recurrence rate, however, these treatments failed to improve the 5 year survival rate significantly. Recently the efficacy of a postoperative chemotherapy was observed in a randomized clinical trial. The administration of methyl-CCNU, Vincristine and 5-fluorouracil after surgical resection of rectal cancer improved both the disease-free survival and the survival rate. Another randomized study showed a benefit of combined post-operative radiotherapy and chemotherapy with methyl-CCNU and 5-FU. Advantages and disadvantages of preoperative irradiation treatment and postoperative irradiation treatment are discussed.