Outcomes after noncurative locoregional treatment in patients with unresectable metastatic colorectal carcinoma.

Abstract

654 Background: A curative hepatic or pulmonary metastasectomy for colorectal carcer is a generally accepted procedure. However, the value of noncurative locoregional therapy for unresectable metastatic colorectal carcer was not well defined. Methods: Of 1,174 patients with unresectable colorectal cancer from 2003 to 2014 retrospectively reviewed, 62 patients received curative regional treatment, 290 patients received locoregional therapy, and 822 patients received standard chemotherapy. Propensity score matching was used to adjust the balance of baseline data between locoregional therapy arm and chemotherapy arm. Kaplan-Meier survival analyses were based on data after propensity score matching. Factors possibly influencing survival were evaluated by univariate and subsequently by multivariate analyses. Results: After propensity score matching, 544 patients were included in this study, 272 in locoregional therapy arm and 272 in chemotherapy arm, respectively. Locoregional therapy included metastasectomy, radiofrequency ablation, percutaneous microwave coagulation therapy and radioactive particle implantation. The addition of locoregional therapy to chemotherapy significantly improved the overall survival with median overall survival 38.73 months (95%CI 34.93-42.54 months) in locoregional therapy arm versus 19.8 months (95%CI 18.06-21.54 months) in chemotherapy arm, respectively, p<0.001. 9 factors were associated with overall survival by univariate analysis, which include primary tumor site, initial stage at first diagnosis, pathological grading, target organ of regional treatment, CA199 and LDH at diagnosis of advanced disease, CEA, CA199 and LDH before regional treatment. Furthermore, CEA (>5ng/ml) and LDH (>245U/L) before regional treatment were identified as independent poor prognostic factors by multivariate analysis. Median overall survival according to the presence of 0, 1, or 2 factors was 49.4 months, 35.7 months, and 27 months. Conclusions: Unresectable metastatic colorectal cancer also benefited from locoregional therapy. Two pre-locoregional treatment risk factors could select the patients most likely to benefit from this strategy.