A 60-year-old woman undergoes a sigmoid resec¬tion for stage III cancer of the colon. The best therapy for this patient consists of operation
|B||and radiation therapy|
|C||and treatment with 5-FU|
|D||and treatment with 5-FU plus levamisole|
a. Patients with stage III disease clearly benefit from adjuvant chemotherapy.
b. The addition of oxaliplatin to the 5-FU/leucovorin regimen (FOLFOX) has resulted in an improvement of disease-free survival rates at 3 years to 78% (compared with 73% with 5-FU/leucovorin alone).
c. Irinotecan (Camptosar) has been investigated as an addition to 5-FU–based therapy in the adjuvant setting, based on its benefit against metastatic disease.
d. Unfortunately, irinotecan has not demonstrated efficacy in the adjuvant setting and is not currently used for the treatment of stage III patients.
e. Continuous-infusion 5-FU is now generally considered to be superior to bolus infusions, with less toxicity.
f. Recently, an oral fluoropyrimidine, capecitabine (Xeloda), has been shown to be at least equivalent to intravenous 5-FU and may have superior efficacy.
g. The treatment of stage IV patients depends on the location and extent of the metastases. Isolated hepatic or pulmonary lesions may be amenable to resection.
h. The newest agents that have been shown to be effective for metastatic disease and are now being studied in the adjuvant setting are the monoclonal antibodies bevacizumab (Avastin) and cetuximab (Erbitux).
i. Cetuximab binds to and inhibits the epidermal growth factor receptor, which is overexpressed in 60% to 80% of colorectal cancers and is associated with a shorter survival time.
j. This agent has shown clinical efficacy in patients with metastatic colorectal cancer, both as monotherapy and in combination with irinotecan and FOLFOX.
k. Bevacizumab, a vascular endothelial growth factor inhibitor, has also improved survival when added to regimens that include irinotecan, 5-FU/leucovorin, or oxaliplatin.