Oligometastases confined one organ from colorectal cancer treated by SBRT

To determine the feasibility and efficacy of stereotactic body radiotherapy (SBRT) for oligometastases from colorectal cancer (CRC). Total of 59 patients with 78 lesions confined to one organ and treated from 2001 to 2006 were involved in this retrospective review. These patients presented with 1-4 metastatic lesions of largest diameter of <7 cm, progressed after chemotherapy, and were amenable to local treatment. The median radiation dose administered was 42 Gy, which was delivered in 3 fractions. Lymph node lesions were most frequent, followed in order by the lung and liver. Five-year overall survival and local control rates were 29 and 19%, respectively. Cumulative gross tumor volume, site of metastasis, and SBRT dose were found to be significantly associated with overall survival. In terms of local control, a cumulative GTV below 23 ml was found to be a significantly favorable prognostic factor. Acute grade 1-2 toxicities occurred in 24 of the 59 patients, and a late grade 4 complication occurred in 2 (3%), and these were relieved by bypass surgery. CRC patients with oligometastases generally fare well after SBRT. In particular, the survival rates of patients with a pelvic LN or a small tumor are promising.