Abstract No. 544 Radioembolization for metastatic colon cancer: survival differences between right- and left-sided primary sites

Abstract

For patients with unresectable colon cancer liver metastases (mCRC), in addition to chemotherapy, interventional radiology procedures may be considered, including radioembolization (RE). A recent multicenter randomized controlled trial of 1st line chemotherapy with or without RE suggested a survival benefit for RE for right-sided but not for left-sided mCRC (1). Further, survival is significantly longer in mCRC patients with primary tumors originating in the left colon compared to the right (2). The purpose of this study is to determine if there is a survival difference in patients with right versus left-sided mCRC treated with RE. A retrospective study was performed of 80 consecutive mCRC patients with liver-only or liver-dominant metastases not suitable for surgery or ablation treated with RE between July 2002 and November 2011. Data collected from medical and public records included demographics, dates of diagnosis, RE and death. Of 80 patients, 37 had left-sided and 29 right-sided primaries with 10 rectum, and one each anorectal, multiple, mid-transverse and unknown. Two patients were alive at the end of follow-up. Overall median survival was 9.0 months from RE and 30.9 mo from colon cancer diagnosis. Median survival from first RE was longer for left (12.1 mo) vs right (6.1 mo) primary sites (p = 0.026). Median survival from diagnosis for left (33.5 mo) vs right (27.0 mo) was not significantly different (p = 0.524). At time of first RE, there were no significant left vs right primary site differences in age, gender, presence of extrahepatic tumor, number of lines of prior chemotherapy, performance status, and tumor-to-liver volume ratio. Following RE, mCRC patients with left-sided primaries had longer median survival than those with right-sided primaries. This difference was not accounted for by differences in other patient or tumor characteristics. These data add to literature describing the impact of primary tumor location on mCRC outcomes and may support a side-based approach to RE treatment selection.