Hye Jin Kim, Gyu-seog Choi, Jun Seok Park, Soo Yeun Park. Kyungpook National University Chilgok Hospital
INTRODUCTION: Lateral pelvic lymph node dissection (LPND), beyond the total mesorectal excision (TME) plane, is selectively suggested for treating suspected lymph node metastasis in the pelvic side-wall in patients with rectal cancer who underwent preoperative chemoradiotherapy. However, there are still controversies about LPND. First one is the indication and another is technical issues. All patients who underwent LPND received preoperative chemoradiotherapy (CRT), therefore, it is difficult to make indication. Additionally, technical difficulties can cause incomplete dissection of lateral pelvic lymph nodes (LPNs), remaining them in the pelvic side-wall. Therefore, we need the method to confirm the completeness of dissection of metastatic LPNs. This study aimed to find the index LPN, which is defined as suspected LPN metastasis, among ICG-bearing LPNs during operation in real-time with matching 3D reconstruction images. In addition, by tracing the change of index LPNs during preoperative CRT, and matching them to the pathologic results in node-by-node setting, we aimed to help to make an indication guideline of LPND.
METHODS: Rectal cancer patients who were anticipated to undergo LPND after preoperative CRT were prospectively enrolled. ICG in a dose of 2.5mg was injected around tumor preoperatively. For 3D reconstruction images, each patient had axial CT scan with contrast (0.6mm slice thickness) before operation. These images were then manipulated with OsiriX (Pixmeo, Geneva, Switzerland). Index LPNs and essential structures in pelvic sidewall, such as obturator nerve, were reconstructed with abdominal arteries from 3D volume rendering. During operation, we matched the ICG-bearing LPN with 3D lymphovascular reconstruction image. All procedures were performed with a laparoscopic or robotic approach.
RESULTS: Seventeen patients underwent TME with LPND after preoperative CRT. Bilateral LPND was performed in six patients. All index LPNs among ICG-bearing lymph nodes were well identified during operation by matching with its corresponding 3D image. Pathologic LPN metastasis was confirmed in 7 patients (41.2%) and in 8 of 23 dissected sidewalls (34.8%). All metastatic LPN were identified among index LPNs. Six (75%) among 8 metastatic LPNs were located in internal iliac area. Three of eight metastatic LPNs (27.5%) were ≥7 mm on pretreatment MRI, and four were ≥5 mm on post-CRT MRI.
CONCLUSION: Index LPN was completely dissected by using dual image-guidance LPND technique including fluorescence and 3D lymphovascular reconstruction. Further studies and long-term oncologic outcome is required the real impact of this procedure on LPND.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 87690
Program Number: S122
Presentation Session: Colorectal 2 Session
Presentation Type: Podium