EUS-Guided Ethanol Lavage with Paclitaxel Injection (EUS-EP) for Cystic Tumors of the Pancreas: Follow-Up Study with Analysis of Response and Its Predictor

Abstract

Background: Cystic tumors of the pancreas (CTP) are detected more and more frequently. It has become a challenging issue to make a management plan for CTP. A substantial proportion of CTP cannot be histologically classified even after extensive evaluation, and therefore ultimately require surgical resection. The pilot study of EUS-guided ethanol lavage reported that complete resolution was achieved in only one-third of patients. Therefore, more effective treatment modalities are required to improve treatment responses. Paclitaxel injection following ethanol lavage was suggested to achieve better response.1 The present study analyzed the response and safety of EUS-EP, and factors which may influence the treatment response among the larger study population. Methods: Nineteen patients were enrolled for EUS-EP by the following inclusion criteria; 1) uni- or oligolocular CTP, 2) indeterminate tumors for which EUS-FNA was required, and 3) CTPs showing size growth during the observation period. Under EUS-guidance, cyst fluid aspiration, ethanol lavage and injection of paclitaxel were performed. The safety of EUS-EP was analyzed by monitoring the patients till the first 30-day follow-up. All patients were followed for > 6 months, and the treatment response and its predictors were analyzed. Using CT images, the volume CTP was calculated by computer estimations of the areas on each axial image and slice thickness. Response is defined as follows; 1) complete resolution (CR): < 5% of original volume (OV), 2) partial resolution (PR): 5 to 25% of OV, 3) persistent cyst: > 25% of OV. Results: The median diameter and volume were 25.0 mm (17-41 mm) and 3.1 mL (1.2-32.5 mL), respectively. Seven tumors were septated. The median CEA level was 58.0 ng/mL (1-8190). The presumed diagnoses were 6 MCNs, 4 SCAs and 9 indeterminate cysts. The median follow-up was 8 months. CR was observed in 15 patients, PR in 3 patients, and a cyst persisted in one patient. In addition, 4 patients with persistent cystic tumors showed gradual decrease in volume during follow-up. The original volume was significantly different between CR and persistent group. However, there was no difference in presence of septation, cyst fluid CEA level, number of MCN. Mild pancreatitis was observed in one patient. Conclusions: Smaller cystic tumor may be better achieved in CR than larger one. EUS-EP appears to be a safe and effective method for treating CTP. Further studies involving larger populations and longer follow-up are warranted.1. Oh HC, Seo DW, Lee TY, et al. New treatment for cystic tumors of the pancreas: EUS-guided ethanol lavage with paclitaxel injection. Gastrointest Endosc 2008 (in press)