First-Line Radiotherapy for Colorectal Cancer Liver Metastases

Selective internal radiotherapy with yttrium-90 resin microspheres (SIRT) has proven beneficial as a third-line or subsequent therapy for patients with colorectal cancer (CRC) liver metastases. To determine the potential benefit of adding SIRT to first-line chemotherapy in this setting, investigators conducted a planned pooled analysis of three industry-sponsored, multicenter, open-label, randomized trials involving more than 1100 patients with liver-predominant metastatic CRC.

Most patients were male (66%) and had colon primaries (71%–76%), synchronous metastases (87%), primary tumors in place (50%–55%), and 25% or less liver involvement (68%–69%); a minority had extra hepatic metastases (35%–36%). Patients received first-line FOLFOX chemotherapy with permissible addition of bevacizumab or anti-EGFR therapy versus chemotherapy sequenced with two intrahepatic infusions of SIRT given during the first two cycles of chemotherapy.

At a median follow-up of 43.3 months, median overall survival was similar with chemotherapy plus SIRT versus chemotherapy alone for all patients (22.6 and 23.3 months, respectively), as well as for those with liver-only metastases (24.5 and 24.6 months). The response rate was higher with SIRT (72% vs. 63%; P=0.0012), as was the rate of response in the liver. However, grade 3 or higher adverse events were more likely with SIRT (odds ratio, 1.42; P=0.0089).