Ethanol Ablation of Neck Metastases from Differentiated Thyroid Carcinoma

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

Ablation of Primary and Recurrent Thyroid Cancer: Current and Future Perspectives

Thyroid cancer is the most common endocrine malignancy, and its incidence is increasing, driven in part by the advent of ultrasound, and subsequent increased detection of small, early thyroid cancers. Yet even for small tumors, thyroidectomy with lymph node dissection remains standard of care. Specific to well-differentiated thyroid cancer, surgery has come under scrutiny as a possible overtreatment, in light of stable and favorable survival rates even as guidelines have allowed fewer radical resections and lymph node dissections over time. Moreover, thyroid cancer unfortunately has a known recurrence rate regardless of therapy, and surgical re-intervention for local structural recurrence is eventually limited by scar. Radioactive iodine therapy, another accepted treatment, is minimally invasive but can only treat patients with iodine-avid tumors. For all of these reasons, image-guided thermal ablation has emerged as a valuable complementary tool as a thyroid-sparing, parathyroid-sparing, voice-sparing, repeatable, minimally invasive outpatient focal therapy for both primary and recurrent well-differentiated thyroid cancers. However, the data are still evolving, and this represents a new patient cohort for some interventional radiologists. Therefore, the goal of this review is to discuss the technique and evidence for ablation of patients with thyroid cancer.

A clinical practice review of percutaneous ethanol injection for thyroid nodules: state of the art for benign, cystic lesions

Percutaneous ethanol injection (PEI) is a widely used treatment option for cystic and predominantly cystic thyroid nodules. It has several advantages over other treatment modalities. Compared to surgery, PEI is less painful, can be performed in the outpatient setting, and carries less risk of transient or permanent side effects. Compared to other minimally invasive techniques such as radiofrequency ablation (RFA), PEI is less expensive and does not require specialized equipment. PEI performs well in the context of cystic nodules. PEI does not perform as well as other techniques in solid nodules, so its use as a primary treatment is limited to cystic and predominantly cystic thyroid nodules. However, PEI is also being explored as an adjunct treatment to improve ablation of solid nodules with other techniques. Here, we provide a clinical review discussing the genesis, mechanism of action, and patient selection with respect to ethanol ablation, as well as the procedure itself. Predictors of operative success, failure, and common adverse events are also summarized. Altogether, PEI allows impressive volume reduction rates with minimal complications. Several recent studies have also evaluated the long-term impact of PEI up to 10 years after treatment and revealed maintenance of robust treatment efficacy with no undesirable long-term sequelae. Thus, PEI remains the treatment of choice for benign but symptomatic cystic and predominantly cystic thyroid nodules.

Long-term Effectiveness of Ethanol Ablation in Controlling Neck Nodal Metastases in Childhood Papillary Thyroid Cancer

Context

Childhood papillary thyroid carcinoma (CPTC), despite bilateral thyroidectomy, nodal dissection and radioiodine remnant ablation (RRA), recurs within neck nodal metastases (NNM) in 33% within 20 postoperative years. These NNM are usually treated with reoperation or further radioiodine. Ethanol ablation (EA) may be considered when numbers of NNM are limited.

Objective

We studied the long-term results of EA in 14 patients presenting with CPTC during 1978 to 2013 and having EA for NNM during 2000 to 2018.

Methods

Cytologic diagnoses of 20 NNM (median diameter 9 mm; median volume 203 mm³) were biopsy proven. EA was performed during 2 outpatient sessions under local anesthesia; total volume injected ranged from 0.1 to 2.8 cc (median 0.7). All were followed regularly by sonography and underwent volume recalculation and intranodal Doppler flow measurements. Successful ablation required reduction both in NNM volume and vascularity.

Results

Post EA, patients were followed for 5 to 20 years (median 16). There were no complications, including postprocedure hoarseness. All 20 NNM shrank (mean by 87%) and Doppler flow eliminated in 19 of 20. After EA, 11 NNM (55%) disappeared on sonography; 8 of 11 before 20 months. Nine ablated foci were still identifiable after a median of 147 months; only one identifiable 5-mm NNM retained flow. Median serum Tg post EA was 0.6 ng/mL. Only one patient had an increase in Tg attributed to lung metastases.

Conclusion

EA of NNM in CPTC is effective and safe. Our results suggest that for CPTC patients who do not wish further surgery and are uncomfortable with active surveillance of NNM, EA represents a minimally invasive outpatient management option.

Ex vivo intranodal administration of sirolimus

BACKGROUND

Immune-mediated adverse effects of current systemic immunosuppression therapy compromise long-term survival of liver transplant recipients. Our recently observed results showed that intranodal delivery of sirolimus induced interleukin (IL)-10-driven CD4+ CD25+ Foxp3+ regulatory T cells. The present report investigated the feasibility of intra-nodal delivery of sirolimus ex vivo into a human liver common bile duct lymph node.

METHODS

We used a discarded donor human liver to directly administer sirolimus into a distal common bile duct lymph node. Sirolimus was injected once using an ultrasound-guided method.

RESULTS

The porta hepatis and its lymph node along the distal common bile duct were exposed. A handheld ultrasound probe (L15-7io, Koninklijke Philips N.V.) with a layer of standoff Aquasonic 100 Ultrasound Transmission Gel (Parker Laboratories, Inc) was applied to the exposed lymph node. Using a 1.0-mL 25G hypodermic needle, 0.05 mL of sirolimus solution was injected directly into the exposed lymph node.

CONCLUSIONS

Under sonographic guidance, direct injection of sirolimus into a hepatic draining lymph node along the common bile duct is accomplished precisely and reliably. Direct administration of therapeutic agents into local lymph nodes is a viable approach for effective targeted immunotherapy.

Clinical Utility of Cabozantinib in the Treatment of Locally Advanced or Metastatic Differentiated Thyroid Carcinoma: Patient Selection and Reported Outcomes

Treatment of differentiated thyroid cancer (DTC) is multidisciplinary and begins with surgical intervention. Often, radioactive iodine is used as the prototype targeted therapy to ablate any residual thyroid tissue or metastatic deposits. While these initial therapeutic modalities are often curative with no need for further treatment, many patients develop radioactive-iodine refractory (RAIR) disease. When patients present with progressive RAIR disease, they often require systemic therapy. Several multikinase inhibitors have been approved for treatment of DTC, with sorafenib and lenvatinib employed in frontline treatment settings since approvals in 2013 and 2015, respectively. While patients have benefited from such treatment, progression is inevitable, and until recently, there were no established second-line options. Cabozantinib was recently approved for treatment of patients with DTC who have progressed on either frontline sorafenib or lenvatinib. Molecular testing for driver mutations or gene fusions, such as BRAF V600E or RET or NTRK fusions, has become standard recommendations for RAIR DTC patients due to excellent treatment options with highly selective targeted therapies, most RAIR DTC patients do not harbor such aberrations or have so-called "undruggable" mutations, making rendering cabozantinib an attractive and feasible treatment option for many patients.

Oncopharmacology in Interventional Radiology

The broad scope of malignancies treated in interventional oncology is mirrored by the breadth of oncotherapeutics, drugs used to treat cancer. Many of these treatments are administered endovascularly, though a group of therapies can be delivered percutaneously. Perhaps the best taxonomy of oncotherapeutics is based on their biological inactivity or activity and the mechanism by which they interact with treated and targeted tissues. As the fields of interventional oncology and oncotherapeutics continue to grow and expand, this framework may provide a more organized approach in helping distinguish and select the best therapy for patients.

Long-Term Efficacy of Ethanol Ablation as Treatment of Metastatic Lymph Nodes From Papillary Thyroid Carcinoma

CONTEXT

Ethanol ablation (EA) is considered an alternative to surgery for metastatic lymph nodes from papillary thyroid carcinoma (PTC) in selected patients.

OBJECTIVE

The aim of this study was to evaluate the long-term efficacy and safety of this treatment.

DESIGN AND SETTING

Adult patients with PTC who had received EA in lymph node metastasis at a tertiary referral center, and were included in a published study from 2011, were invited to participate in this follow-up study.

METHODS

Radiologic and medical history were reviewed. Ultrasound examination of the neck was performed by radiologists, and clinical examination was performed by an endocrine surgeon. Response was reported according to predefined criteria for satisfactory EA treatment. Adverse events associated with EA were evaluated. Cause of death was reported for deceased patients.

RESULTS

From the 2011 study, 51 of 63 patients were included. Forty-four patients were reexamined (67/109 lesions) and 7 patients were deceased. Median follow-up time from primary surgery was 14.5 years. Median follow-up from the latest performed EA in the 2011 study was 11.3 years. Local control was permanently achieved in most patients (80%). Recurrence within an ablated node was registered in 13 metastases in 10 patients. Seven of these patients also had recurrent disease elsewhere in the neck. No major side effects were reported.

CONCLUSION

EA is a minimally invasive procedure with a low risk of complications. Our data suggest that EA is a safe and efficient treatment, providing excellent results for a large group of patients in the long term.

Inability of Radioiodine Remnant Ablation to Improve Postoperative Outcome in Adult Patients with Low-Risk Papillary Thyroid Carcinoma

OBJECTIVE

To determine whether radioiodine remnant ablation (RRA) reduces cause-specific mortality (CSM) or tumor recurrence (TR) rate after bilateral lobar resection (BLR).

PATIENTS AND METHODS

There were 2952 low-risk adult papillary thyroid cancer (LRAPTC) patients (with MACIS scores <6) who underwent potentially curative BLR during 1955-2014. During 1955-1974, 1975-1994, and 1995-2014, RRA was administered in 3%, 49%, and 28%. Statistical analyses were performed using SAS software.

RESULTS

During 1955-1974, the 20-year CSM and TR rates after BLR alone were 1.0% and 6.8%; rates after BLR+RRA were 0% (P=.63) and 5.9% (P=.82). During 1975-1994, post-BLR 20-year rates for CSM and TR were 0.3% and 7.5%; after BLR+RRA, rates were higher at 0.9% (P=.31) and 12.8% (P=.01). When TR rates were examined separately for 448 node-negative and 317 node-positive patients, differences were nonsignificant. In 1995-2014, post-BLR 20-year CSM and TR rates were 0% and 9.2%; rates after BLR+RRA were higher at 1.4% (P=.19) and 21.0% (P<.001). In 890 pN0 cases, 15-year locoregional recurrence rates were 3.4% after BLR and 3.7% after BLR+RRA (P=.99). In 740 pN1 patients, 15-year locoregional recurrence rates were 10% higher after BLR+RRA compared with BLR alone (P=.01). However, this difference became nonsignificant when stratified by numbers of metastatic nodes.

CONCLUSION

RRA administered to LRAPTC patients during 1955-2014 did not reduce either the CSM or TR rate. We would therefore not recommend RRA in LRAPTC patients undergoing BLR with curative intent.

Prevalence and characteristics of vagus nerve variations on neck ultrasonography

Purpose

We aimed to evaluate the true prevalence and characteristics of vagus nerve (VN) variations using the carotid artery (CA) and the internal jugular vein (C-I axis).

Methods

We examined patients who underwent neck ultrasonography (US) conducted by a single operator. A VN variation was defined as a VN located anterior or medial to the C-I axis. The subtypes of VN variation were classified as anterolateral, anteromiddle, anteromedial, and medial based on the relative location of the VN to the CA. The primary outcome parameters were the prevalence of VN variations and differences according to side, age, and sex.

Results

Out of 536 patients, right and left VN variations were identified in 20 (3.7%) and 186 (34.7%), respectively (P<0.001). The anteromiddle type was the commonest type observed on both sides. Eight right (1.5%) and 50 left VNs (9.3%) were located <2 mm from the lateral border of the ipsilateral thyroid gland (P<0.001). The prevalence of VN variations in male and female patients was 42.1% and 32.7%, respectively (P=0.029), and that in patients aged <20, 20-39, 40-59, and ≥60 years was 23.8%, 22.5%, 34.4%, and 47.4%, respectively (P<0.001).

Conclusion

Variations in the VN position were relatively common on US. The variations primarily involved the left VN in the lower cervical region, and an increasing prevalence with age was observed.

Long-Term Results of Treating With Ethanol Ablation 15 Adult Patients With cT1aN0 Papillary Thyroid Microcarcinoma

Background

Currently acceptable management options for patients with adult papillary thyroid microcarcinoma (APTM) range from immediate surgery, either unilateral lobectomy or bilateral lobar resection, to active surveillance (AS). An alternative minimally invasive approach, originally employed for eliminating neck nodal metastases, may be ultrasound-guided percutaneous ethanol ablation (EA). Here we present our experience of definitively treating with EA 15 patients with APTM.

Patients and Methods

During 2010 through 2017, the 15 cT1aN0M0 patients selected for EA were aged 36 to 86 years (median, 45 years). Tumor volumes (n = 17), assessed by sonography, ranged from 25 to 375 mm³ (median, 109 mm³). Fourteen of 15 patients had 2 ethanol injections on successive days; total volume injected ranged from 0.45 to 1.80 cc (median, 1.1 cc). All ablated patients were followed with sonography and underwent recalculation of tumor volume and reassessment of tumor perfusion at each follow-up visit.

Results

The ablated patients have now been followed for 10 to 100 months (median, 64 months). There were no complications and no ablated patient developed postprocedure recurrent laryngeal nerve dysfunction. All 17 ablated tumors shrank (median 93%) and Doppler flow eliminated. Median tumor volume reduction in 9 identifiable avascular foci was 82% (range, 26%-93%). After EA, 8 tumors (47%) disappeared on sonography after a median of 10 months. During follow-up no new PTM foci and no nodal metastases have been identified.

Conclusions

Definitive treatment of APTM by EA is effective, safe, and inexpensive. Our results suggest that, for APTM patients who do not wish neck surgery and are uncomfortable with AS, EA represents a well-tolerated and minimally invasive outpatient management option.

Elimination of Locoregional Recurrences and Skin Metastases in Papillary Thyroid Cancer by Ethanol Ablation and Mohs Surgery

Ultrasound-guided percutaneous ethanol ablation procedures for locoregional recurrences in papillary thyroid carcinoma (PTC) can be repeatedly performed over years. Skin metastases (SM) from PTC generally portend a lethal prognosis. Our patient case report demonstrates the innovative use in low-risk PTC (LRPTC) of treatment modalities designed to prevent neck re-explorations and capable of eliminating both locoregional recurrences and SM. In 2004, a 48-year-old man presented with neck nodal metastases due to PTC. He underwent a near-total thyroidectomy and nodal dissection, confirming an 8-mm PTC involving 2 ipsilateral node metastases. Postoperatively, he received 2 doses of radioactive iodine (RAI) for remnant uptake (cumulative dose 338 mCi); posttherapy scanning was unrevealing. In 2007, he underwent right neck dissection for further node metastases. In 2008, a guided biopsy confirmed a level IV node metastasis. He was referred to our institution for ethanol ablation. Two node metastases were ablated and subsequently disappeared. During 2010-2016, he developed an additional 6 node metastases, which were treated with ethanol ablation; all disappeared on high-resolution sonography. FDG-PET-CT scans in 2009 and 2016 were negative for distant spread. In 2016, a SM in his right neck was removed by dermatologic surgery. In 2017-2018, 2 further SM were excised with negative margins, one after Mohs surgery. He has now been disease-free for 20 months. In conclusion, despite 3 neck surgeries and 2 RAI therapies, our patient repeatedly developed both locoregional recurrences and SM. All 11 disease foci were eliminated with minimally invasive procedures which should more often be considered as effective treatment options in LRPTC.