Biology of rectal cancer--the rationale for targeted therapy.

Rectal cancer will affect approximately 40,000 people per year in the United States. Surgical resection through meticulous total mesorectal excision, combined with preoperative chemoradiation, is considered the standard of care for patients with stage II or III disease. However, as many as a third of patients will develop local or distant progression of disease. Understanding the biology of rectal cancer will allow for a more rational approach to treatment. This report discusses aspects of tumor biology, including angiogenesis and apoptosis, which may allow for better targeted therapy. The ultimate goal will be individualized treatment with the therapy that will maximize tumor response while minimizing toxicity.