Impact of Standardized Rhus verniciflua Stokes Extract as Complementary Therapy on Metastatic Colorectal Cancer: A Korean Single-Center Experience

Abstract

To investigate the clinical feasibility of the standardized Rhus verniciflua Stokes (RVS) extract for the metastatic colorectal cancer (mCRC), experimentally proven to have anticancer activities. From July 2006 to November 2007, patients with conventional chemotherapy refractory mCRC were checked. After fulfilling inclusion/exclusion criteria, 36 patients were eligible for the final analysis. Overall survival and adverse events of patients treated with RVS in the aftercare period were determined. On October 21, 2008, a total of 26 patients died while the remaining 10 patients were alive with evidence of disease. The median RVS administration period was 2.7 months (95% confidence interval, 1.9-3.5). The median overall survival for the entire population was 10.9 months (95% confidence interval, 5.6-16.1) and 1-year survival rate was 44.4%, which is compatible with external controls. By survival analysis using Cox proportional hazards model, the performance status and the prior chemotherapy regimen number significantly affected overall survival. Adverse reactions to the RVS treatment were mostly mild and self-limiting. Complementary treatment with the standardized RVS extract might be beneficial for patients with mCRC, since it positively affected overall survival without significant side effects. This study suggests that RVS could be a natural anticancer agent candidate for the treatment of colorectal adenocarcinoma.