Immunocytochemistry Profile of Benign Thyroid Nodules Not Responding to Thermal Ablation: A Retrospective Study.

Purpose: Thermal ablations (TA) are gaining ground as alternative options to conventional therapies for symptomatic benign thyroid nodules. Little is known about the impact of nodule biology on the outcomes of TA. The aim of our study was to evaluate the baseline immunocytochemistry profile of thyroid nodules that were poorly responsive to TA in order to identify potential predictors of the treatment response. Methods: From a cohort of 406 patients with benign thyroid nodules treated with TA and followed for 5 years, we retrospectively selected two groups of patients: NONRESPONDERS (patients who did not respond to TA and were later surgically treated) and RESPONDERS (patients who responded to TA). The fine-needle aspiration cytology (FNAC) slides obtained before TA were stained for Galectin-3, HBME-1, CK-19, and Ki-67. Results: Benign nodules of NONRESPONDERS (n = 19) did not express CK-19 (p = 0.03), as compared to RESPONDERS (n = 26). We combined the absence of CK-19 and the presence of Ki-67 to obtain a composite biomarker of resistance to TA, which discriminated between likelihood of retreatment and no retreatment with an AUC of 0.68 (95%CI: 0.55-0.81) and a sensitivity, specificity, PPV, and NPV of 29%, 91%, 71%, and 64%, respectively. Conclusion: In benign thyroid nodules, the absence of CK-19 was associated with resistance to TA, while the presence of CK-19 was predictive of response to TA. If confirmed, this finding could provide rapid and inexpensive information about the potential outcome of TA on benign thyroid nodules. In addition, as CK-19 can be expressed in adenomatous hyperplasia, it could be speculated that these nodules, rather than follicular adenomas, might be better candidates for TA.

Five-Year Results of Radiofrequency and Laser Ablation of Benign Thyroid Nodules: A Multicenter Study from the Italian Minimally Invasive Treatments of the Thyroid Group.

Background: Radiofrequency ablation (RFA) and laser ablation (LA) are effective treatments for benign thyroid nodules. Due to their relatively recent introduction into clinical practice, there are limited long-term follow-up studies. This study aimed to evaluate technique efficacy, rate of regrowth, and retreatment over 5 years after RFA or LA and to identify predictive factors of outcome. Methods: In this multicenter retrospective study, the rates of technique efficacy, regrowth, and retreatment were evaluated in 406 patients treated with either RFA or LA, and followed for 5 years after initial treatment. Propensity score matching was used to compare treatments. Cumulative incidence studies with hazard models were used to describe regrowth and retreatment trends, and to identify prognostic factors. Logistic regression models and receiver operating characteristic analyses were used for risk factors and their cutoffs. Results: RFA and LA significantly reduced benign thyroid nodule volume, and this reduction was generally maintained for 5 years. Technique efficacy (defined as a reduction ≥50% after 1 year from the treatment) was achieved in 74% of patients (85% in the RFA and 63% in the LA group). Regrowth occurred in 28% of patients (20% in the RFA and 38% in the LA group). In the majority of cases, further treatment was not required as only 18% of patients were retreated (12% in the RFA and 24% in the LA group). These data were confirmed by propensity score matching. Cumulative incidence studies showed that RFA was associated with a lower risk of regrowth and a lower risk of requiring retreatment over time. Overall, technique inefficacy and regrowth were associated with low-energy delivery. Retreatments were more frequent in young patients, in large nodules, in patients with lower volume reduction at 1 year, and in cases of low-energy delivery (optimal cutoff was 918 J/mL for RFA). Conclusions: Both thermal ablation techniques result in a clinically significant and long-lasting volume reduction of benign thyroid nodules. The risk of regrowth and needing retreatment was lower after RFA. The need for retreatment was associated with young age, large baseline volume, and treatment with low-energy delivery.

A comparison of laser with radiofrequency ablation for the treatment of benign thyroid nodules: a propensity score matching analysis.

PURPOSE: To compare technique efficacy and safety of laser ablation (LA) and radiofrequency ablation (RFA) in treatment of benign thyroid nodules. MATERIALS AND METHODS: Institutional review board approval was obtained, and patients' consent was waived. 601 nodules were treated from May 2009 to December 2014 at eight centres, 449 (309 females, age 57 ± 14 years) with LA and 152 (107 females, age 57 ± 14 years) with RFA. A matched cohort composed of 138 patients from each group was selected after adjustment with propensity score matching. Factors influencing volume reduction at 6 and 12 months and complications were evaluated. RESULTS: No significant differences were observed in the baseline characteristics between groups after propensity score matching adjustment. Mean nodule reduction at 6 and 12 months was -67 ± 19% vs. -57 ± 21% (p < 0.001) - 70 ± 19% vs. -62 ± 22% (p = 0.001) in LA group and in RFA group, respectively. Nodules with volume >30 mL had significantly higher percentage volume reduction at 6 and 12 months (-69 ± 19 vs. -50 ± 21, p = 0.001) and (-73 ± 18 vs. -54 ± 23 8, p = 0.001) in the LA group than in the RFA group, respectively. In both groups, operator's skills affected the results. Major complications occurred in 4 cases in each group (p = 0.116) Conclusions: LA and RFA showed nearly similar outcome but LA was slightly more effective than RFA in large nodules. Operator's skills could be crucial in determining the extent of nodule volume reduction regardless of the used technique.