Systemic Treatment of Colon Cancer

Colorectal cancer is the third most common cancer worldwide, and is the third leading cause of cancer mortality with an estimated 50, 310 deaths occurring in 2014 in the United States. There has been a steady decline in the incidence of colorectal cancer over the past 30 years, which is largely due to early endoscopic screening. Surgical management remains the mainstay of treatment for early and locally-advanced non-metastatic colon cancers, and in patients with initially resectable liver or lung-only metastases. Systemic therapies have shown to significantly improve outcomes when given in the neo-adjuvant and/or adjuvant setting in these patients, and when used as principal therapy in patients with unresectable metastatic disease. The addition of adjuvant chemotherapy in patients with Stage III and high risk stage II disease significantly improves recurrence free survival. Patients with oligometastatic Stage IV colorectal cancer (CRC) who receive post-operative chemotherapy have a median OS that exceeds 5 years in some studies. The advent of targeted molecular therapies has further helped improve outcomes in patients with metastatic CRC cancer. Patients with unresectable metastatic disease who receive a combination of systemic chemotherapy and targeted agents have a median overall survival over 2 years today. It is important that patients be exposed to all active agents during their disease course to achieve this survival benefit. In this review article we summarize important clinical trials that have led to an evidence-based approach to the management of colon cancer.