Adjunctive local therapy in metastatic colorectal cancer in an unselected cohort: Improved patient-survival in comparison to systemic therapies.
4096 Background: Patients with distant metastases in colorectal cancer have a poor prognosis and a low overall survival (OS). In addition to systemic treatments and irradiation, the tumor burden can be reduced by loco-regional therapeutics, including microwave ablation (MWA), radiofrequency therapy (RFA) and trans-arterial chemoembolization (TACE) available. To evaluate the benefit of such local therapies, we compared OS of a single-centre study population to a reference population of patients who underwent no loco-regional treatment within the German Tumor Registry Colorectal Cancer (TKK). Methods: The study population consists of a cohort of 51 patients (n = 51) treated loco-regionally in addition to systemic therapy. The patients were recruited in a single cancer centre in Mülheim, Germany during the years 2006 to 2015. A reference population of 788 patients was chosen from a prospective, longitudinal registry of the TKK. Time to event data analysis included the estimation of Kaplan-Meier cumulative survival probabilities and hazard ratios (HR) with corresponding 95% confidence intervals (95% CI) from Cox proportional hazards regression. Results: The median OS was 31.3 months (95% CI 26.8 - 41.6) in the study population, as compared to the reference population, where it was 21.9 months (95% CI 20.1 – 24.6). Patients with liver and lung metastases in the study population had an OS of 41.6 months (95% CI 30.5 – 78.2), the corresponding patients from the reference population 21.7 months (95% CI 16.7 – 24.6). Furthermore, patients in the reference group had a 1.79-fold death-rate, as compared to patients treated with additional loco-regional therapy (HR = 2.02; 95% CI: 1.29-3.16). Conclusions: Additional treatment with loco-regional therapies of distant metastases in patients with metastatic colorectal cancer appears to be associated with improved OS by nearly 10 months compared to systemic treatments only. [Table: see text]