CEA radioimmunotherapy with 131I-labetuzumab improves survival post salvage resection of colorectal cancer metastases in the liver

Abstract

3627 Background: Although complete (R0) resection of liver metastases (LM) remains the treatment of choice for colorectal cancer (CRC) patients amenable to curative therapy, only about one-third survive 5 years. The objective of this study was to evaluate the safety and efficacy of radioimmunotherapy (RAIT) post salvage resection of LM. Methods: Twenty-three patients who underwent surgery for LM of CRC received a dose of 40–60 mCi/m2 131I-labetuzumab, a humanized monoclonal antibody against carcinoembryonic antigen (CEA). Safety (n=23), disease-free survival (DFS) and overall survival (OS) (n=19) were determined, and efficacy then compared retrospectively to similar control patients treated at the same institution and during a similar timeframe, but without RAIT. Results: With a median follow-up of 64 months, median OS from the first liver resection for RAIT patients was 68.0 months (95% CI: 46.0 months, infinity) vs. 31.0 months (95% CI: 24.0, 59.0 months) for the control group (p=0.004). DFS for RAIT patients had a median of 18.0 months (95% CI: 11.0, 31.0 months) vs. 12.0 months (95% CI: 6.5, 21.5 months) for the controls (p=0.284). Five-year survival was 51.3% and 7.4% for RAIT and control groups, respectively. Also, RAIT benefited patients independently of bilobar involvement, the size and number of LM, or the resection margins. The major side effect was a transient myelosuppression, resulting mostly in a grade =< 3 neutropenia and/or thrombocytopenia. Conclusion: Since both median OS and the 5-year survival rate appear to be improved with adjuvant RAIT post complete LM resection in CRC, these results justify further evaluation in a multicenter, randomized trial. No significant financial relationships to disclose.