Percutaneous Laser Ablation of Unresectable Metastatic Lesions in Retroperitoneal Regions: A Series of 4 Cases

Abstract

Metastasis in retroperitoneal lymph nodes is one of the signs of advanced stage or terminal stage of malignancy. We performed a trial to assess the safety and efficacy of ultrasonography (US)-guided local neodymium-doped yttrium aluminum garnet (Nd:YAG) laser ablation for metastatic lymph nodes in the retroperitoneal region. We evaluated 4 cases of retroperitoneal metastatic lymph nodes treated using US-guided Nd:YAG laser ablation. At first, a plane-cut optic fiber (300 μm in diameter) along with the sheath of a 21-G needle was advanced with a 10-mm bared fiber into the lesions. Then laser ablation under ultrasonographic guidance was performed by a Nd:YAG laser-beam fiber (EchoLaser X4, ESAOTE, Italy) at a wavelength of 1064 nm. The output power of laser was 5 W and the time was approximately 5-6 minutes. Power and energy were selected based on previous experience. Immediately after laser ablation, the entire area without enhancement under CEUS was defined as success. If still enhanced in the target lesion, it was regarded as residual area. Supplementary energy was applied to destroy an area larger than the lesional volume. The selective number of fibers was based on the size of the lesion. The tumor size and location near organs and vascular structures were evaluated using computed tomography (CT) or magnetic resonance image (MRI) and US every three months. Preoperative and postoperative tumor markers of Carcinoembryonic Antigen (CEA), Alpha Fetoprotein (AFP) and Carbohydrate Antigen 19-9 (CA19-9) levels were measured. In our study, The total energy was between 2600 J and 3600 J. During laser energy application, ultrasound images showed a hyperechoic area around the fiber tip. It was obtained after a delay about 80-120s. Then the hyperechoic region expanded slowly forward. When the procedure finished, the whole lesion was covered with hyperechoic zone. There were no major complications detected in the patients during the laser ablation. All the pre-admission symptoms like abdominal pain, weakness have relieved. At the 3-month follow-up, all lesions were nearly completely ablated with mild discomfort, including pain and fever. Percutaneous laser ablation could be a theoretically promising approach for retroperitoneal metastatic lesions. Large-scale studies on laser ablation for metastatic retroperitoneal lymph nodes are necessary to confirm our findings.