[Medical treatment of colorectal cancer].

Colorectal cancer is the second leading cause of cancer-related death in the US in both sexes after lung cancer. In 1995 colorectal cancer became the third most common neoplasm after lung and prostate cancer in men and after lung and breast carcinomas in women. The etiologic factors related to this disease are unknown although environmental, genetic, dietary and familial factors have been implicated. From the standpoint of the treatment it is important to remark that a high percentage of patients with colorectal cancer are curable if the disease is diagnosed in early stages. Adjuvant therapy with 5-fluorouracil (5-FU) and levamisole (lev) has shown an increase in the cure rate in stage III (Dukes'C) colon cancer patients. In rectal cancer patients adjuvant therapy with chemotherapy and radiation therapy increased the cure rate in stages II (Dukes' B2) and III patients. When colorectal cancer is disseminated (stage IV or Dukes'D), it is incurable in the majority of the patients. In fact, the only curative possibility in this group of patients is, when indicated, surgical resection of the metastatic focus. If resection is unfeasible, palliative treatment with 5-FU-based chemotherapy is the usual approach. Regardless of the advances made in treatment, almost 50% of the colorectal cancer patients still die due to progression of their disease. Better programs of primary and secondary prevention, new therapeutic modalities and better chemotherapeutic agents will be necessary to improve survival in colorectal cancer patients.