PS02.078: FEASIBILITY OF PREOPERATIVE STAGING WITH USPIO ENHANCED MRI IN PATIENTS WITH RESECTABLE ESOPHAGEAL CARCINOMA (PRECIES STUDY)

Abstract

Abstract Background In operable patients suffering from esophageal cancer, the percentage of patients without metastatic lymph nodes found after neoadjuvant chemoradiotherapy (nCRT) is 69%. Extensive lymph node dissections during esophagectomy may be omitted or minimized in these patients, reducing associated morbidity. Recently, MRI with ultrasmall superparamagnetic iron oxide nanoparticles (USPIO, ferumoxtran-10) has been reintroduced to detect metastatic lymph nodes in prostate cancer. The aim of this study is to assess the feasibility of USPIO-MRI to detect loco-regional lymph node metastases in patients with esophageal cancer. Methods USPIO-nanoparticles are intravenously infused 24 to 36 hours before MRI. USPIO-enhanced MRI is performed before and after nCRT. After nCRT, patients are scanned under general anesthesia immediately prior to surgery in the MR system of the hybrid MITeC operation room with controlled mechanical ventilation. During controlled prolonged apneu, a four-minute iron-sensitive MRI acquisition is used to visualize suspicious esophageal lymph nodes without motion artefacts. Resected specimens, still containing USPIO, are measured ex-vivo in a preclinical 7T MR system before histopathological examination. A radiological assessment of the presence of suspicious lymph nodes in-vivo is matched to the ex-vivo nodes on preclinical MRI, providing the ground truth for the presence of metastases. Results Currently, three patients were included in the study of which one patient has been examined before and after nCRT. MRI under anesthesia prior to surgery with controlled mechanical ventilation was possible resulting in a clinically relevant spatial resolution to visualize possible malignant lymph nodes. Suspicious nodes were identified and could be matched using corresponding anatomical landmarks to the ex-vivo MRI, which showed good visual agreement with esophageal specimen after resection. Conclusion A successful method was proposed to validate USPIO-enhanced MRI to detect metastatic lymph nodes in patients with esophageal cancer. Matching ex-vivo USPIO-MRI images with histopathology results provides direct information for validation of in vivo USPIO-MRI and characteristics of loco-regional lymph nodes. Final results on the feasibility of USPIO-MRI to detect metastatic lymph nodes after nCRT are still awaited. Feasibility and preliminary values of the accuracy of the technique are the starting point for a phase two study. Disclosure All authors have declared no conflicts of interest.