Percutaneous laser ablation: a new contribution to unresectable high-risk metastatic retroperitoneal lesions?

Abstract

Background & aims: 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.

Methods: We evaluated 4 cases of retroperitoneal metastatic lymph nodes treated using US-guided Nd:YAG laser ablation. Additionally, we reviewed the PubMed database for articles on thermal ablation of retroperitoneal lesions until March 2016, without language limitations.

Results: In our study, all lesions were nearly completely ablated with mild discomfort, including pain and fever at the 3-month follow-up. In the literature review, a total of 398 patients with 491 retroperitoneal tumors were identified, and complications after the procedure included enterovesical fistula, fecal incontinence, and hematoma.

Conclusions: Percutaneous laser ablation could be a theoretically promising approach for retroperitoneal metastatic lesions. ClinicalTrials.gov number: NCT02822053.

Keywords: ablation; laser ablation; lymph nodes; oncology; retroperitoneal tumor.

Conflict of interest statement

CONFLICTS OF INTERESTS

The authors state that there is no conflict of interests regarding the publication of this paper.

Figures

Figure 1. Metastasis of lymph nodes in a 60-year-old man who had undergone gallbladder cancer resection

MR image of T2-weighted and substance phase showed enlarged, round lymphoma around retroperitoneal abdominal aorta a.,b. (arrowhead). Preoperative US image revealed a hypoechoic mass 2.52*2.26 cm c.. Intraoperative sonogram showed the one d. (arrowhead) and two needles e. (arrowhead) inserting into the tumor, suggesting the distances (cm) of needle tip to tumor margin (anterior: 1.61; 1.54). Afterwards, the mass had local enhancement under ultrasound scanning f., and increased unenhanced low-density areas in arterial g. (arrowhead) and substance phase h. (arrowhead) on contrast-enhanced CT scan.

Figure 2. A 43-year-old man with metastatic lymph nodes originating from liver cancer

Axial contrast-enhanced MR image was obtained at the abdominal setting. An oval, mildly high signal intensity is present close to aorta abdominalis a. (arrowhead). Preoperative CEUS images showed the lesion with rapid wash-in and wash-out in arterial b.. Axial gray-scale US image indicated intraoperative ethanol ablation c.. Before initial laser ablation, the mass is shown in the retroperitoneum under US guidance d.. Two laser fibers parallelly ablated the tumor under the guidance of US, which appraised the distances (cm) of needle tip to mass boundary e. (anterior: 1.9; 1.8; left: 0.9; right: 0.7), and subsequent immediate CEUS image showing a large and central filling defect f..

Figure 3. Axial abdominal MR image performed 13 days after initial ablation revealed the peripheral remanent tumor

a. (white arrows), 6-week follow-up CT scan of the venous phase measuring 4*3.1 cm with area of central necrosis 2.3*1.8 cm b. (white arrows). Before the second laser ablation, a central well-defined hyperecho surrounding unenhanced hypoechoic active areas c.. During ablation, immediate US scan showed the left part of tumor obvious enhancement d., and the next day a finding that most response appeared e., f.. At a follow-up visit 11 days, a contrast-enhanced CT venous phase image revealed the enlarged areas of tumor necrosis g. (white arrows). Then two months later, there was reduced mass necrosis of 2.43*1.7 cm at T1 h. (white arrows), T2 i. (white arrows) and substance phase j. (white arrows) of MR image.

Figure 4. A 60-year-old man with metastatic lymph nodes close to the duodenum, pancreas, stomach and blood vessels

Preoperative T2-weighted a. (white arrows), substance phase MR scan indicated a tumor close to the hepatic portal vein, pancreas and stomach b. (white arrows). Axial US image of the retroperitoneal region showed the mild hyperechoic area c. (white arrows). After fourth ablation, US image showed the lesion had complete response d. (white arrows). Substance phase of CT obtained 3 days after US-guided PLA revealed no signs of malignancy e. (white arrows), and then one month later, substance phase of MR image has low signal intensity f. showing complete necrosis of the tumour (white arrows).

Figure 5. A 60-year-old man with metastatic lymph nodes beside the inferior vena cava

Preoperative MR image in T2-weighted a. (white arrows) and substance phase b. (white arrows) suggested a mass of 3.9*2.1 cm in size close to the vena cava. Then with the guidance of US, two laser fibers parallelly were insered into and ablated the tumor c.-e. (white arrows). One month later, MRI scan indicated the lesion was complete necrosis f. (white arrows).