Evaluation of Low-dose Irinotecan and Cyberknife® SBRT to Treat Colorectal Cancer With Limited Liver Metastasis

The purpose of this study is to determine the effects of CyberKnife stereotactic body radiotherapy in combination with irinotecan chemotherapy in patients with colon or rectal cancer that has spread to the liver. Conventional radiation therapy has a limited role in the treatment of patients with liver metastases because the radiation doses are limited by liver toxicity. The CyberKnife system is a type of radiation machine that precisely focuses large doses of x-rays on the tumor, so that injury from radiation to the nearby normal tissue will be minimal. It is approved by the U.S. Food and Drug Administration to treat tumors, lesions and conditions anywhere in the body when radiation therapy is required. While the device is no longer classified as "investigational", the best treatment dose and times are still being evaluated. Chemotherapy delivered with radiation therapy can increase the effectiveness of treatment, and may allow for a lower dose of radiation therapy to be utilized, thereby limiting negative side effects. In this study, patients will receive Cyberknife radiosurgery directed to liver metastasis for 3-5 treatments, given every other day. Irinotecan 40mg/m2 will be administered intravenously daily for 3-5 days (5 treatments within 10 elapsed days), and prior to radiation therapy. Patients will have follow-up visits at months 1,2,4,6,9,12,15,18, 24, 30, 36, and every 6 months thereafter for 3 years.