Treatment of esophageal tumors using high intensity intraluminal ultrasound: first clinical results

Abstract

Background: Esophageal tumors generally bear a poor prognosis. Radical surgery is generally the only curative method available but is not feasible in the majority of patients; palliative therapy with stent placement is generally performed. It has been demonstrated that High Intensity Ultrasound can induce rapid, complete and well-defined coagulation necrosis. Thus, for the treatment of esophageal tumors, we have designed an ultrasound applicator that uses an intraluminal approach to fill up this therapeutic gap.

Methods: Thermal ablation is performed with water-cooled ultrasound transducers operating at a frequency of 10 MHz. Single lesions extend from the transducer surface up to 10 mm in depth when applying an intensity of 14 W/cm2 for 10s. A lumen inside the therapy applicator provides path for an endoscopic ultrasound imaging probe operating at a frequency of 12 MHz. The mechanical rotation of the applicator around its axis enables treatment of sectorial or cylindrical volumes. This method is thus particularly suitable for esophageal tumors that may develop only on a portion of the esophageal circumference. Previous experiments were conducted from bench to in vivo studies on pig esophagi.

Results: Here we report clinical results obtained on four patients included in a pilot study. The treatment of esophageal tumors was performed under fluoroscopic guidance and ultrasound imaging. Objective tumor response was obtained in all cases and a complete necrosis of a tumor was obtained in one case. All patients recovered uneventfully and dysphagia improved significantly within 15 days, allowing for resuming a solid diet in three cases.

Conclusion: This clinical work demonstrated the efficacy of intraluminal high intensity ultrasound therapy for local tumor destruction in the esophagus.

Figures

Figure 1

Intraluminal ultrasound applicator. (a) Schematic diagram of the applicator. (b) US device for the treatment of esophageal tumors.

Figure 2

Head of the intraluminal high intensity ultrasound applicator. The ultrasound imaging probe is in front of the therapeutic transducer to image the region of interest.

Figure 3

Gross positioning of the therapeutic ultrasound applicator. The therapeutic ultrasound applicator was placed in the esophagus under fluoroscopy after positioning metallic clips on the patient's skin.

Figure 4

Sonogram of an esophageal tumor obtained during treatment.

Figure 5

Patient 1. Tumor necrosis was observed on the whole length of the tumor, except at the proximal part where necrosis appeared to be incomplete. (a) Control endoscopy 8 days after the treatment. The necrosis was pushed distally with the endoscope. T, remaining tumor. N, Tumor necrosis. (b) EUS examination 8 days after the treatment.

Figure 6

Patient 2. Control endoscopy of the esophageal tumor. (a) before and (b) 10 days after the treatment.