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Friday, October 25, 2019

Evaluation of Outcomes following Radiofrequency Ablation for Treatment of Parotid Tail Warthin Tumors


Clinical question
Is radiofrequency (RF) ablation safe and efficacious for parotid Warthin tumor ablation?

Take-away point
Warthin tumor ablation could be an option for treatment of Warthin tumors.

Reference
Yu-Chen Tung, et al. Evaluation of Outcomes following Radiofrequency Ablation for Treatment of Parotid Tumors. Journal of Vascular and Interventional Radiology. Oct, 2019: 30; 10, 1574-1580.

Click for abstract

Study design
Retrospective

Funding source
Self-funded or unfunded

Setting
Single-center




Figure 1. Patient 6, a 58-year-old man with a Warthin tumor in the parotid tail area, underwent a preoperative MR imaging evaluation followed by RF ablation using the moving shot technique. (a) Photograph showing assumed facial nerve and branches (yellow lines) and danger zone (red dotted line). RF ablation was performed following the route from the posterior-inferior site of the mandibular angle to avoid damage to the facial nerve. The labels 2a–2d indicate the scan positions from cranial to caudal. (b) Real-time US sagittal oblique image showing the maximum diameter axis of the Warthin tumor. The tip of the electrode was positioned in the deepest and most remote part of the tumor, then sequential ablation was performed by moving the electrode tip backward and forward, from bottom to top. (c) The extent of the ablated zone was determined by the echogenic changes around the electrode. When a hyperechoic zone appeared, the electrode tip was moved backward.


Summary

Warthin tumors are benign parotid tumors that most typically present in middle-age male smokers. Surgery is the current standard of care, however this carries risk associated with anesthesia, iatrogenic complications, and cosmetic defects. Currently, there is some controversy over the need for surgery as malignant transformation is rare. Ablation was proposed as an alternative, and this study aimed to evaluate the efficacy and safety of ultrasound guided RF ablation of parotid Warthin tumors.

7 men with biopsy proven Warthin tumors were treated with RF ablation. Patient’s were included if the tumor was located in the tail of the parotid, the mass was growing and palpable or caused cosmetic concerns, and the patient’s refused surgery. RF ablation was performed using the moving shot technique under local anesthesia. Parotid tumor reduction and cosmetic scale were noted. Average tumoral volume decreased from 14.6 cm3 to 5.3 cm3 1 month post procedure, which was statistically significant. Cosmetic score also demonstrated statistically significant improvement. No peri-procedural complications were noted, however 1 patient experienced parotitis with hematoma 12 days post procedure.


Commentary

While observation of Warthin tumors is reasonable given the low rates of malignant transformation and possible complications of standard surgery, this is limited due to risks associated with observation including variable growth rates, more difficult dissection with larger tumors, and patient anxiety. Ablation may offer a low risk alternative to standard surgery to obviate the need for general anesthesia, lower side effect profile, and smaller incisions. RF ablation is able to be contained to within the tumor capsule. Additionally, with the patient only under local anesthesia, the ablation probe can be immediately relocated with any patient report of pain thus minimizing risk of nerve injury.

This study is limited due to the very small size, retrospective nature, and short follow up. RF ablation is not expected to be comparable to surgery as the ablation is kept within the confines of the tumor and is only possible in parotid tail tumors. However, in locations with diagnostic imaging expertise, and experience with head and neck ablation, RF ablation could be a suitable alternative to select patients who wish to avoid surgery.

Post Author David M Mauro, MD
Assistant Professor
Department of Radiology, Vascular and Interventional Radiology
University of North Carolina

@DavidMauroMD

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