Long-term outcome of ultrasound-guided percutaneous ethanol ablation of selected “recurrent” neck nodal metastases in 25 patients with TNM stages III or IVA papillary thyroid carcinoma previously treated by surgery and 131I therapy

Statement and Recommendations on Interventional Ultrasound as a Thyroid Diagnostic and Treatment Procedure

The recently published guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on interventional ultrasound (INVUS)-guided procedures summarize the intended interdisciplinary and multiprofessional approach. Herewith, we report on recommendations for interventional procedures for diagnosis and treatment of the thyroid gland.

Ethanol and thermal ablation for malignant thyroid tumours

Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid malignancy and has a good prognosis and low mortality rate. Surgery is the standard treatment for patients with primary and recurrent thyroid cancer. Although patients with PTC usually exhibit excellent treatment outcome, the incidence of recurrence in the neck ranges from 20% to 59%. When a patient with thyroid cancer is contraindicated for surgery, ultrasound (US)-guided ablation techniques, including ethanol ablation (EA) and thermal ablations, are suggested alternatives. In this review, we evaluated the indications, devices, techniques, clinical outcomes, and complications associated with US-guided EA and thermal ablations based on available scientific evidence and expert opinions regarding the use of ablation for primary and recurrent thyroid cancers.

Kikuchi-Fujimoto disease in the regional lymph nodes with node metastasis in a patient with tongue cancer: A case report and literature review

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare self-limiting disorder typically affecting the cervical lymph nodes (LNs), which is often misdiagnosed as other LN-associated diseases. KFD frequently presents with necrotic lesions and recurrences, which are also features of metastatic LNs. Clinicians may thus suspect LN metastasis when they encounter ipsilateral cervical lymphadenopathy in a patient with head and neck cancer. The present study reports the case of a 48-year-old man with tongue cancer and KFD affecting the right edge of his tongue and ipsilateral cervical LNs. LN metastasis was initially suspected, but pathological examination of the dissected LNs revealed one necrotic metastatic lesion and two necrotic KFD lesions. Ipsilateral cervical lymphadenopathy recurred 6 years after the initial surgery, and it was not possible to differentiate clinically between a second primary tumor and recurrent KFD prior to treatment. To the best of our knowledge, this is the first reported case of simultaneous tongue cancer, regional LN metastasis and KFD. This highlights the requirement to consider KFD in the event of LNs with necrotic lesions but no cancerous cells. A combination of clinical and pathological approaches may aid in the diagnosis of KFD, in addition to ruling out LN metastasis in initial and recurrent lymphadenopathies. The present study indicate that a diagnosis of KFD should be considered in patients with head and neck cancer that exhibit necrotic LNs lacking cancerous cells. This is important, as misdiagnosis of KFD as LN metastasis may lead to unnecessary adjuvant therapy.

Long-term outcomes of ethanol injection therapy for locally recurrent papillary thyroid cancer

The standard treatment regimen for locally recurrent lesions is total thyroidectomy, or complete removal of the recurrent thyroid lesion within the thyroid bed. However, reoperation increases the risk of complications and patients have to undergo general anesthesia. Percutaneous ethanol injection therapy represents a far less invasive procedure without general anesthesia and with lower risk of complications. Thirty-four patients who received PEIT at Yonsei University Medical Center between October 2002 and August 2009 for recurrent cervical nodal metastases of differentiated papillary thyroid cancer were included in this retrospective study. During a minimum follow-up of 60 months, treatment outcomes were determined by measuring the lesion size prior to the first injection and 3 months after the last injection. A total of 46 recurrent lesions were detected in 34 patients. Five patients underwent surgery and PEIT was administered to the remaining 19 and 22 lesions in the central compartment and lateral neck lymph nodes, respectively. Size increases were observed in seven (17.1%) lesions, whereas no changes in size and decreases were detected in 10 (24.4%) and 24 (58.5%) lesions. Patients with increased lymph nodes were significantly older (65.3 ± 14.4 vs. 48.2 ± 16.3 years; p = 0.02) and had smaller sizes (9.3 ± 1.0 vs. 12.3 ± 6.4 mm; p = 0.012). Although reoperation remains the first-line treatment for recurrent thyroid cancer, PEIT may be considered as a treatment option in selected patients with lesions larger than 1 cm who are ineligible for surgery or have refused reoperation.

Knockdown of lncRNA-PANDAR suppresses the proliferation, cell cycle and promotes apoptosis in thyroid cancer cells

Long non-coding RNAs (lncRNAs) have been found to show important regulatory roles in various human cancers. Lnc-RNA PANDAR is a novel identified lncRNA that was previously reported to show abnormal expression pattern in various cancers. However, little is known of its expression and biological function in thyroid cancer. Here, we used the quantitative real-time PCR (qRT-PCR) to determine the expression of PANDAR in 64 thyroid cancer tissues. We found that expression of PANDAR was up-regulated in thyroid cancer tissues compared with adjacent non-tumor tissues. Functional assays in vitro demonstrated that knockdown of PANDAR could inhibit proliferation, cell cycle progression, induces the apoptosis, inhibit invasion of thyroid cancer cells. Thus, our study provides evidence that PANDAR may function as a potential target for treatment for patients with thyroid cancer.

Comprehensive management of recurrent thyroid cancer: An American Head and Neck Society consensus statement: AHNS consensus statement

This American Head and Neck Society (AHNS) consensus statement focuses on the detection and management of recurrent thyroid cancer. This document describes the radiologic approach to defining structural recurrent disease and the operative and nonoperative rationale in addressing identified structural disease to create equipoise in the personalized treatment strategy for the patient. The recommendations of this AHNS multidisciplinary consensus panel of the American Head and Neck Society are intended to help guide all multidisciplinary clinicians who diagnose or manage adult patients with thyroid cancer. The consensus panel is comprised of members of the American Head and Neck Society and its Endocrine Surgical Committee, and there is representation from medical endocrinology and both national and international surgical representation drawn from general/endocrine surgery and otolaryngology/head and neck surgery. Authors provided expertise for their respective sections, and consensus recommendations were made regarding the evaluation and treatment of recurrent thyroid cancer. Evidence-based literature support is drawn from thyroid cancer studies, recurrent thyroid cancer studies, and American Thyroid Association (ATA) guidelines. The manuscript was then distributed to members of the American Head and Neck Society Endocrine Committee and governing counsel for further feedback. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1862-1869, 2016.

Meta-analysis of radiofrequency ablation for treating the local recurrence of thyroid cancers

OBJECTIVES

Our aim was to evaluate the efficacy of ultrasound-guided radiofrequency ablation (RFA) for localized recurrent thyroid cancers.

METHODS

We did a systematic review and meta-analysis of the scientific literature by searching the PubMed, Embase, Web of Science,Scopus and the Cochrane Library up to November 26, 2015. We assessed the pooled standard mean difference (SMD) of nodule volume, largest diameter and serum thyroglobulin (Tg) level by comparing pre-RFA with post-RFA using fixed or random-effects model. The Newcastle-Ottawa Scale was used to evaluate the methodological quality of the included studies, risk of bias in the selective populations, comparability of groups and exposure.

RESULTS

We finally identified nine articles including 189 patients (male: 54 and female: 135) with 255 tumor lesions, who underwent ultrasound (US)-guided RFA beyond the mean 6 months of follow-up. The results showed that tumor volume (SWD: 0.77, 95 % CI: 0.57-0.97, I (2) = 25.9 %, p = 0.231), largest diameter (SWD: 1.56, 95 % CI: 0.94-2.17, I (2) = 82.6 %, p < 0.001) and Tg level (SWD: 0.52, 95 % CI: 0.30-0.73, I (2) = 0 %, p = 0.493) were decreased and no significant publication bias was detectable.

CONCLUSIONS

The pooled data indicated that the prognosis improved for patients with localized recurrent thyroid cancers and RFA is a promising treatment for these patients with infeasible surgery.

Therapeutic options in papillary thyroid carcinoma: current guidelines and future perspectives

The treatment of papillary thyroid cancer is now based on individual patient risk and response to therapies. Molecular techniques are increasingly being used to risk stratify and to guide therapeutic decisions. There have been advances in the treatment of local disease through surgery or radioiodine. Directed techniques can target metastatic disease including bisphosphonates, radiofrequency ablation or radiotherapy. Systemic therapies such as tyrosine kinase inhibitors show great promise although such treatment must be individualized. Future therapies will target treating radioiodine refractory disease.

Efficacy and Safety of Radiofrequency and Ethanol Ablation for Treating Locally Recurrent Thyroid Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this study was to evaluate the efficacy and safety of radiofrequency ablation (RFA) and ethanol ablation (EA) for treating locally recurrent thyroid cancer.

MATERIALS AND METHODS

Ovid-MEDLINE and EMBASE databases were searched for studies on the efficacy and safety of RFA and EA for treating locally recurrent thyroid cancer. The pooled proportions of the volume reduction ratio (VRR) ≥50%, complete disappearance, changes in serum level of thyroglobulin (Tg), recurrence, and complications were assessed using random-effects modeling. Heterogeneity among studies was determined using the chi-square statistic for the pooled estimates and the inconsistency index I(2). To overcome heterogeneity, sensitivity analysis was performed.

RESULTS

Ten eligible studies were included, with a total sample size of 270 patients and 415 thyroid nodules. The pooled proportion of VRR ≥50% after RFA (100%, recalculated 100%; I(2) = 100%, recalculated I(2) = 55.3%) was higher than that after EA (89.5%; I(2) = 82.4%; p = 0.2764); the pooled proportion of complete disappearance after RFA (68.8%) was higher than that after EA (53.4%; p = 0.3384); and the pooled proportion of recurrence after RFA (0.0%) was lower than that after EA (2.4%, adjusted 1.6%; p = 0.9766). However, these differences were not statistically significant. In addition, the pooled proportion of reduction in serum level of Tg after RFA was 71.6% and after EA was 93.8% (p < 0.0001). The pooled proportion of complications of both RFA (5.8%, adjusted 1.6%) and EA (1.6%) were low (p = 0.8479). The mean number of RFA sessions was <1.3 in five of six RFA studies, and the number of EA sessions was more than two in three of four EA studies.

CONCLUSION

Both RFA and EA are acceptable treatment modalities to manage locally recurrent thyroid cancer in terms of efficacy and safety for poor surgical candidates or those who refuse surgery.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Long noncoding RNA PVT1 modulates thyroid cancer cell proliferation by recruiting EZH2 and regulating thyroid-stimulating hormone receptor (TSHR)

The purposes of this study were to investigate the potential roles of long noncoding RNA (lncRNA) PVT1 in thyroid cancer cell proliferation and to explore their possible mechanisms. A total of 84 patients who were diagnosed as having thyroid cancer (papillary thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC), and anaplastic thyroid carcinoma (ATC)) in Renji Hospital were enrolled in this study. Expressions of lncRNA PVT1 in thyroid cancer tissues and cell lines (IHH-4, FTC-133, and 8505C) were analyzed using RT-polymerase chain reaction (PCR) and western blotting analysis. The effects of lncRNA PVT1 expression on thyroid cancer cell proliferation and cell cycle were analyzed using flow cytometry. Furthermore, the effects of lncRNA expression on thyroid-stimulating hormone receptor (TSHR) expression and polycomb enhancer of zeste homolog 2 (EZH2) were also analyzed using RNA immunoprecipitation (RIP) assay and chromatin immunoprecipitation (ChIP) assay, respectively. Compared to the controls, lncRNA PVT1 was significantly up-regulated in thyroid tissues, as well as in three kinds of tumor cell lines (P < 0.05). Silenced PVT1 significantly inhibited thyroid cell line IHH-4, FTC-133, and 8505C cell proliferation and arrested cell cycle at G0/G1 stage and significantly decreased cyclin D1 and TSHR expressions (P < 0.05). Moreover, lncRNA PVT1 could be enriched by EZH2, and silencing PVT1 resulted in the decreased recruitment of EZH2. This study suggested that lncRNA PVT1 may contribute to tumorigenesis of thyroid cancer through recruiting EZH2 and regulating TSHR expression.

Managing the increasing diagnosis of papillary micro-cancer of thyroid

There has been an increase in the incidence of thyroid cancer in the last decade, mainly due to the increase in imaging. A majority of the cases are for papillary cancers <1 cm. Mortality from thyroid cancer has stayed stable, thus, there is a large pool of papillary micro-cancer of thyroid in the general population without clinical significance. For these cancers a different approach is needed and active surveillance or less aggressive management should be offered as options. Controlled studies of minimally invasive procedures such as ethanol ablation are needed. If surgery is chosen, lobectomy alone should be adequate. Cases of occult papillary micro-cancer with local and distant metastases are very rare and should be managed according to the staging and risk category of the disease.

Percutaneous Ethanol Sclerotherapy of Symptomatic Nodules Is Effective and Safe in Pregnant Women: A Study of 13 Patients with an Average Follow-Up of 6.8 Years

Background. Because of the increased risk of surgery, thyroid nodules causing compression signs and/or hyperthyroidism are concerning during pregnancy. Patients and Methods. Six patients with nontoxic cystic, four with nontoxic solid, and three with overt hyperthyroidism caused by toxic nodules were treated with percutaneous ethanol injection therapy (PEI). An average of 0.68 mL ethanol per 1 mL nodule volume was administered. Mean number of PEI treatments for patients was 2.9. Success was defined as the shrinkage of the nodule by more than 50% of the pretreatment volume (V0) and the normalization of TSH and FT4 levels. The average V0 was 15.3 mL. Short-term success was measured prior to labor, whereas long-term success was determined during the final follow-up (an average of 6.8 years). Results. The pressure symptoms decreased in all but one patient after PEI and did not worsen until delivery. The PEI was successful in 11 (85%) and 7 (54%) patients at short-term and long-term follow-up, respectively. Three patients underwent repeat PEI which was successful in 2 patients. Conclusions. PEI is a safe tool and seems to have good short-term results in treating selected symptomatic pregnant patients. Long-term success may require repeat PEI.

Serum thyroglobulin (Tg) monitoring of patients with differentiated thyroid cancer using sensitive (second-generation) immunometric assays can be disrupted by false-negative and false-positive serum thyroglobulin autoantibody misclassifications

CONTEXT

Reliable thyroglobulin (Tg) autoantibody (TgAb) detection before Tg testing for differentiated thyroid cancer (DTC) is critical when TgAb status (positive/negative) is used to authenticate sensitive second-generation immunometric assay ((2G)IMA) measurements as free from TgAb interference and when reflexing "TgAb-positive" sera to TgAb-resistant, but less sensitive, Tg methodologies (radioimmunoassay [RIA] or liquid chromatography-tandem mass spectrometry [LC-MS/MS]).

OBJECTIVE

The purpose of this study was to assess how different Kronus (K) vs Roche (R) TgAb method cutoffs for "positivity" influence false-negative vs false-positive serum TgAb misclassifications that may reduce the clinical utility of reflex Tg testing.

METHODS

Serum Tg(2G)IMA, TgRIA, and TgLC-MS/MS measurements for 52 TgAb-positive and 37 TgAb-negative patients with persistent/recurrent DTC were compared. A total of 1426 DTC sera with TgRIA of ≥ 1.0 μg/L had false-negative and false-positive TgAb frequencies determined using low Tg(2G)IMA/TgRIA ratios (<75%) to indicate TgAb interference.

RESULTS

TgAb-negative patients with disease displayed Tg(2G)IMA, TgRIA, and TgLC-MS/MS serum discordances (% coefficient of variation = 24 ± 20%, range, 0%-100%). Of the TgAb-positive patients with disease, 98% had undetectable/lower Tg(2G)IMA vs either TgRIA or TgLC-MS/MS (P < .01), whereas 8 of 52 (15%) had undetectable Tg(2G)IMA + TgLC-MS/MS associated with TgRIA of ≥ 1.0 μg/L. Receiver operating characteristic curve analysis reported more sensitivity for TgAb method K vs R (81.9% vs 69.1%, P < .001), but receiver operating characteristic curve cutoffs (>0.6 kIU/L [K] vs >40 kIU/L [R]) had unacceptably high false-negative frequencies (22%-32%), whereas false positives approximated 12%. Functional sensitivity cutoffs minimized false negatives (13.5% [K] vs 21.3% [R], P < .01) and severe interferences (Tg(2G)IMA, <0.10 μg/L) (0.7% [K] vs 2.4% [R], P < .05) but false positives approximated 23%.

CONCLUSIONS

Reliable detection of interfering TgAbs is method and cutoff dependent. No cutoff eliminated both false-negative and false-positive TgAb misclassifications. Functional sensitivity cutoffs were optimal for minimizing false negatives but have inherent imprecision (20% coefficient of variation) that, exacerbated by TgAb biologic variability during DTC monitoring, could cause TgAb status to fluctuate for patients with low TgAb concentrations, prompting unnecessary Tg method changes and disrupting Tg monitoring. Laboratories using reflexing should limit Tg method changes by considering a patient's Tg + TgAb testing history in addition to current TgAb status before Tg method selection.

Ultrasound-guided percutaneous ethanol injection in papillary thyroid cancer metastatic lymph-nodes

Post-operative neck nodal metastases are detected in 9-20 % of papillary thyroid cancer (PTC). Ultrasound-guided ethanol injection (UPEI) has been used with promising results in the treatment of PTC patients with limited number of lymph-node metastases.

CLINICAL CASE

We report the imaging and biochemical documentation of UPEI results in four metastatic neck lymph-nodes of papillary thyroid-cancer. A significant reduction both in the diameter of the lymph-nodes and in the serum thyroglobulin levels were observed in all cases and have been reported in a step-by-step sequence.

CONCLUSION

the UPEI treatment is a simple and suitable tool for the treatment of PTC cervical lymph-node metastases.

How sensitive (second-generation) thyroglobulin measurement is changing paradigms for monitoring patients with differentiated thyroid cancer, in the absence or presence of thyroglobulin autoantibodies

PURPOSE OF REVIEW

To discuss new insights regarding how sensitive (second-generation) thyroglobulin immunometric assays (TgIMAs), (functional sensitivities ≤0.10 μg/L) necessitate different approaches for postoperative thyroglobulin monitoring of patients with differentiated thyroid cancer (DTC), depending on the presence of thyroglobulin autoantibodies (TgAbs).

RECENT FINDINGS

Reliable low-range serum thyroglobulin measurement has both enhanced clinical utility and economic advantages, provided TgAb is absent (∼75% DTC patients). Basal [nonthyroid-stimulating hormone (TSH) stimulated] TgIMA measurement obviates the need for recombinant human TSH stimulation because basal TgIMA below 0.20 μg/L has comparable negative predictive value (>95%) to recombinant human TSH-stimulated thyroglobulin values below the cutoff of 2 μg/L. Now that radioiodine remnant ablation is no longer considered necessary to treat low-risk DTC, the trend and doubling time of low basal thyroglobulin values arising from postsurgical thyroid remnants have recognized prognostic significance. The major limitation of TgIMA testing is interference by TgAb (∼25% DTC patients), causing TgIMA underestimation that can mask disease. When TgAb is present, the trend in TgAb concentrations (measured by the same method) can serve as the primary (surrogate) tumor-marker and be augmented by thyroglobulin measured by a TgAb-resistant class of method (radioimmunoassay or liquid chromatography-tandem mass spectrometry).

SUMMARY

The growing use of TgIMA measurement is changing paradigms for postoperative DTC monitoring. When TgAb is absent, it is optimal to monitor the basal TgIMA trend and doubling time (using the same method) in preference to recombinant human TSH-stimulated thyroglobulin testing. When TgAb is present, interference renders TgIMA testing unreliable and the trend in serum TgAb concentrations per se (same method) can serve as a (surrogate) tumor-marker.

Chemical ablation therapy of recurrent mediastinal nodal metastasis in post-radiotherapy cancer patients

The aim of our study was to evaluate the treatment of post-radiotherapy recurrent mediastinal nodal metastasis. Post-radiotherapy esophageal cancer patients with mediastinal lymph node recurrence were enrolled in this study. Patients were randomized into the radiation (±chemotherapy) or the chemoablation group. Patients randomized to the chemoradiotherapy group received additional radiotherapy, second-line chemotherapy, or both. Patients randomized to the chemoablation group received CT-guided percutaneous chemical ablation. Clinical remission was assessed at 1 month by contrast CT. Reirradiation dose ranged from 2,200 to 3,600 cGy depending on dose-limiting constraints in consideration of prior radiotherapy dose. The RECIST criteria were used in the evaluation of response to therapy. The median length of follow-up is 6 months. Thirty-one patients were enrolled in the study. In the chemoradiation group, all patients underwent CT imaging at 1-month follow-up. Among these patients, seven had progressive disease, five had stable disease (SD), and four had partial response (PR). The 6-month survival rate was 12.5%. In the chemoablation group at 1-month follow-up, 12 patients had SD and three patients had PR, and the 6-month survival rate was 46.6%. Our results suggest that chemoablation therapy as salvage treatment after post-radiotherapy relapse is efficacious and safe.

The advent of ultrasound-guided ablation techniques in nodular thyroid disease: towards a patient-tailored approach

Surgery is the long-established therapeutic option for benign thyroid nodules, which steadily grow and become symptomatic. The cost of thyroid surgery, the risk of temporary or permanent complications, and the effect on quality of life, however, remain relevant concerns. Therefore, various minimally invasive treatments, directed towards office-based management of symptomatic nodules, without requiring general anaesthesia, and with negligible damage to the skin and cervical tissues, have been proposed during the past two decades. Today, ultrasound-guided percutaneous ethanol injection and thermal ablation with laser or radiofrequency have been thoroughly evaluated, and are accessible procedures in specialized centres. In clinical practice, relapsing thyroid cysts are effectively managed with percutaneous ethanol injection treatment, which should be considered therapy of choice. In solid non-functioning thyroid nodules that grow or become symptomatic, trained operators may safely induce, with a single session of laser ablation treatment or radiofrequency ablation, a 50% volume decrease and, in parallel, improve local symptoms. In contrast, hyperfunctioning nodules remain best treated with radioactive iodine, which results in a better control of hyperthyroidism, also in the long-term, and fewer side-effects. Currently, minimally invasive treatment is also investigated for achieving local control of small size neck recurrences of papillary thyroid carcinoma in patients who are poor candidates for repeat cervical lymph node dissection. This particular use should still be considered experimental.