US-guided microwave ablation for primary hyperparathyroidism: a safety and efficacy study

Future Directions in the Treatment of Thyroid and Parathyroid Disease

The surgical management of thyroid and parathyroid disease has evolved considerably since the era of Theodor Kocher. We review the current trends in thyroid and parathyroid surgery concerning robotic surgery for remote access, the use of parathyroid autofluorescence detection technology to aid in the prevention of hypocalcemia as well as the use of thermal ablation to target thyroid nodules in a minimally invasive way. We also discuss how artificial intelligence is being used to improve the workflow and diagnostics preoperatively as well as for intraoperative decision-making. We also discuss potential areas where future research may enhance outcomes.

Case report: Microwave ablation is a safe and effective method for primary hyperparathyroidism in pregnancy

Primary hyperparathyroidism (PHPT) is a rare disease in pregnancy and endangers the health of both pregnant women and fetuses. However, the treatments are very limited for PHPT and most of them are unsatisfactory because of the peculiar state in pregnancy. The only curable method is parathyroidectomy which can be safely performed in the second trimester of pregnancy. In this case, we reported a pregnant woman with primary parathyroid adenoma presenting hypercalcemia and severe vomit at the end of first trimester. Finally, she got cured by microwave ablation at the end of first trimester and gave birth to a healthy baby boy.

Clinical and Economic Evaluation of Ultrasound-Guided Radiofrequency Ablation vs. Parathyroidectomy for Patients with Primary Hyperparathyroidism: A Cohort Study

RATIONALE AND OBJECTIVES

To compare the clinical and economic effects of ultrasound (US)-guided radiofrequency ablation (RFA) with parathyroidectomy (PTX) for primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

From April 2014 to April 2021, 123 PHPT patients who received US-guided RFA or PTX were studied. Propensity score (PS) matching was used to balance the baseline data of the two groups. The rates of cure, recurrent and persistent PHPT, and complications were compared. A Chinese healthcare system perspective cost minimization analysis was conducted.

RESULTS

After PS matching, 37 patient pairs (1:1) were created for the two groups. Follow-up was 27.2 ± 10.6 months and 28.8 ± 16.1 months for the RFA and PTX groups, respectively. At the last follow-up, there was no evidence of differences regarding clinical cure rate between the two groups (RFA vs. PTX, 91.9% vs. 94.6%, p = 1.000). Recurrent PHPT did not develop in any patient. One patient in each group had persistent PHPT. The incidence of complications and side effects, except postoperative pain (RFA vs. PTX, 16.2% vs. 40.5%, p = 0.020), were no significant difference between the two groups (all, p > 0.05). The incremental cost was -$284.00; thus, RFA was more cost-effective. For patients with employee medical insurance or resident medical insurance, the incremental costs (RFA vs. PTX) were -$391.94 and -$49.43, respectively.

CONCLUSION

There were no significant differences in efficacy and safety between RFA and PTX. As the incremental cost for RFA compared with PTX was negative, RFA may be used as a more cost-effective nonsurgical treatment alternative for PHPT.

Efficacy and safety of radiofrequency ablation for primary and secondary hyperparathyroidism: a retrospective study

There is now growing interest in the use of Ultrasound-guided radiofrequency ablation (RFA) to treat hyperparathyroidism. But the efficacy and limitations of this treatment have not been described in sufficient detail. Assessing and contrasting the effectiveness and safety of RFA in treating primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT). This retrospective study included 57 HPT patients (48 for PHPT and 9 for SHPT) who underwent RFA between January 2017 and April 2021. The serum intact parathyroid hormone (iPTH) and calcium, hyperplastic parathyroid volume, volume reduction rate (VRR) before and after RFA, clinical success rate, symptoms, and complications were analyzed and compared. In SHPT group, bone pain (7/9, 77.8%), skin pruritus (4/9, 44.4%), and multiple hyperplastic parathyroid glands (4/9, 44.4%) were more common compared to the PHPT group. After 12 months of follow-up, the serum iPTH, calcium, and the volume of PHPT and SHPT groups had decreased by more than 60%, 10%, and 90%, respectively (P < 0.05). In the VRR, 13 glands of SHPT (72.2%) and 42 glands of PHPT (87.5%) had achieved the clinical success. In addition, the preoperative and postoperative serum iPTH were higher in the SHPT group than in the PHPT group (P < 0.05). In terms of the serum iPTH and calcium, the PHPT group had substantially higher rates of clinical success, with 42 patients (87.5%) and 46 patients (95.8%) meeting the criteria, respectively compared to 3 patients (33.3%) and 6 patients (66.7%) of SHPT group (P < 0.05). After RFA, the clinical symptoms improved in both groups. The overall incidence of complications (hoarseness and postoperative hematoma) of RFA in the two groups was 10.5% (6/57), and hoarseness (3/9, 33.3%) of SHPT group was more common than PHPT group. All the complications were resolved spontaneously within 12 months after symptomatic treatments. In the treatment of PHPT and SHPT, ultrasound-guided RFA is both successful and safe. PHPT patients have better results in restoring normal iPTH by RFA, and have no considerable difference with the SHPT patients in terms of serum calcium, the volume of the ablation area, and the VRR.

Ultrasound-guided microwave and radiofrequency ablation for primary hyperparathyroidism: a prospective, multicenter study

OBJECTIVES

To prospectively investigate the efficacy and safety of ultrasound (US)-guided microwave ablation (MWA) and radiofrequency ablation (RFA) for primary hyperparathyroidism (PHPT).

METHODS

We performed a prospective multicenter study of MWA and RFA for PHPT between August 2017 and October 2020 at five centers. Laboratory testing was performed pre- and post-ablation and followed for at least 6 months. The primary outcome was the cure rate. Secondary outcomes were complications and dynamic changes in serum levels of PTH, calcium, phosphorus, and ALP after ablation.

RESULTS

A total of 132 participants (mean age, 57.33 ± 13.90 years), with 141 parathyroid nodules (median maximal diameter, 1.55 cm) undergoing either MWA or RFA, were enrolled in the study. The technique success rate was 99.29% (140/141). The follow-up period was 6-36 months (median, 12 months). The cure rate was 80.30% (106/132). Pre-ablation PTH level was the independent factor associated with cure rate (Odds ratio (OR), 0.22; 95% CI, 0.07-0.69; p = 0.0090). There was no difference in cure rate between the MWA group and the RFA group (80.22% vs. 80.49%, p = 0.971). The only main complication was hoarseness (5.30%).

CONCLUSIONS

US-guided MWA and RFA for PHPT is an effective and safe procedure in the treatment of PHPT. Pre-ablation PTH level is the key factor affecting the cure rate after MWA and RFA.

KEY POINTS

• To our knowledge, this is the first prospective multicenter clinical trial with ultrasound-guided MWA and RFA for primary hyperparathyroidism. • There was no difference in cure rate between the MWA and RFA groups for primary hyperparathyroidism. The overall cure rate was 80.30%. • Pre-ablation PTH level was the independent factor associated with cure rate (odds ratio (OR), 0.22; 95% CI, 0.07-0.69; p = 0.0090).

Efficacy and safety of radiofrequency ablation for primary and secondary hyperparathyroidism with or without previous parathyroidectomy: a retrospective study

INTRODUCTION

This study aimed to investigate and compare the therapeutic efficacy and safety of ultrasound-guided radiofrequency ablation (RFA), between primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT) patients, with or without previous parathyroidectomy (PTX).

SUBJECTS AND METHODS

A total of 21 patients (7 PHPT, 14 SHPT) underwent RFA for hyperparathyroidism (HPT) at Kaohsiung Chang Gung Memorial Hospital, Taiwan. Five of the 14 SHPT patients had previously received PTX. The laboratory data, volume change of each parathyroid nodule, symptomatic scores, and complications were analyzed and compared between all groups at 1 and 7 days, and at 1, 3, 6, and 12 months after RFA.

RESULTS

After RFA, the volume reduction ratio (VRR) for all patients at the last follow-up was 93.76%, and clinical symptoms significantly improved. At 12 months, all PHPT patients achieved successful treatment of intact PTH (iPTH). In SHPT patients, the mean iPTH value significantly decreased 1-day post-RFA, subsequently exhibiting a transient rebound which proceeded to decrease, with 57.1% reaching successful treatment standards. SHPT patients with PTX showed a lower complication score, shorter ablation time, higher iPTH baseline and outcomes, and lower VRR, compared to patients without PTX. The serum calcium level significantly decreased to normal range in 85.7% of all patients at 12 months. Severe hypocalcemia occurred in 23.8% at 1 week, and all were corrected with calcium supplements.

CONCLUSIONS

RFA demonstrates a therapeutic efficacy similar to PTX. It can thus be considered an effective alternative treatment for PHPT, SHPT, or post-PTX patients who are unsuitable for another PTX.

Predicting ultrasound-guided thermal ablation benefit in primary hyperparathyroidism

OBJECTIVES

Ultrasound (US)-guided thermal ablation for primary hyperparathyroidism (PHPT) is a relatively novel minimally invasive treatment. The recurrence rate after ablation is between 10 and 15%. The characteristics of patients who can benefit from thermal ablation therapy are not clear yet. The aim of this research was to investigate the validity of a parathyroid hormone (PTH)-based classifier for stratifying patients with PHPT.

METHODS

A total of 171 patients were screened, 148 (86.5%) of whom were eligible and were divided into development (n = 104) and external validation (n = 44) cohorts. The potential relationship between the PTH-based classifier and the cure rate of patients was initially assessed in the primary cohort and then validated in the external validation cohort. The nomogram was computed from the logistic regression model.

RESULTS

A cut-off of PTH < 269.1 pg/mL or ≥ 269.1 pg/mL as the optimal prognostic threshold in the training cohort was generated to stratify the patients into low-risk and high-risk groups. Patients with PTH levels < 269.1 pg/mL in the training cohort had a higher cure rate than patients with PTH levels ≥ 269.1 pg/mL (p < 0.001). The PTH level remained the strongest predictor of the cure rate in all cohorts. Furthermore, a nomogram based on the PTH level was developed to predict the cure rate in the training cohort and it performed well in the external validation cohort (AUC: 0.816, 95%CI 0.703 to 0.930; AUC: 0.816, 95%CI 0.677 to 0.956).

CONCLUSIONS

The PTH-based classifier may help with individualised treatment planning for selecting patients who may benefit from thermal ablation.

KEY POINTS

• This is the first analysis of predictors affecting the outcome of US-guided thermal ablation of primary hyperparathyroidism and the findings can be used to identify the potential beneficiary population of thermal ablation of primary hyperparathyroidism. • Parathyroid hormone (PTH) was confirmed as an independent prognostic factor, as it not only showed good accuracy in stratifying patients into high- and low-risk groups in the training and validation cohorts but also outperformed the clinical model. • This study developed and validated a model to predict the treatment success of thermal ablation of primary hyperparathyroidism.

Evaluation of the Early Results of Percutaneous Ethanol Ablation in Patients with Primary Hyperparathyroidism

Percutaneous ethanol ablation (PEA) is an alternative non-surgical method for the treatment of patients with primary hyperparathyroidism (PHPT), suitable in cases with comorbidities and high surgical risk.

The aim of the present study was to evaluate the results of PEA in patients with PHPT at the early stages of follow-up.

Materials and methods: The study included 35 patients (30 women and 5 men, mean age 59.7 ± 12.4 years) with biochemical and hormonal data of PHPT and localized parathyroid adenoma (PTA) by ultrasound, nuclear scan, FNB with cytology and evaluation of PTH in the needle washout. All patients were at high surgical risk or refused surgical treatment. PEA was applied and changes in the PTA volume and calcium-phosphate metabolism were monitored at the third (M3) and sixth (M6) months after the procedure.

Results: Normocalcaemia was achieved in 26 patients (74.3%) at M3 and persisted at M6 in 22 of them. A second course of PEA was administered in 11 patients with persistent hypercalcaemia at M3 and M6, respectively. Compared to the baseline, the mean PTA volume decreased significantly by 53% at M3 and 67% at M6 (p < 0.001). Side effects including local pain, edema and dysphonia were observed in 5 patients (14.3%).

Conclusion: PEA is an efficient and safe treatment modality for the management of PHPT. A significant reduction in PTA volume and a normalization of serum calcium and PTH levels were observed at the early stages of follow-up.

Ultrasound-guided thermal ablation for hyperparathyroidism: current status and prospects

BACKGROUND

Hyperparathyroidism (HPT) is classified into primary HPT (PHPT), secondary HPT (SHPT), tertiary HPT (THPT), and pseudohyperparathyroidism. Parathyroid surgery is generally reserved for patients with symptomatic PHPT and asymptomatic patients who meet the surgical guideline criteria. However, the risk of complications and mortality after parathyroid gland surgery increases with increasing patient age.

AIM

This study aimed to review existing research on laser ablation, radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound in the treatment of HPT and analyze its application prospects.

CONCLUSIONS

Thermal ablation is a good alternative treatment for patients with parathyroid hyperplasia who do not meet the criteria or decline surgery. Being a type of minimally invasive treatment, ultrasound-guided thermal ablation has the advantages of easy operation, rapid recovery, and reusability and is used widely.

Risk factors influencing cure of ultrasound-guided microwave ablation for primary hyperparathyroidism

OBJECTIVE

To evaluate the potential risk factors influencing cure rate of ultrasound-guided microwave ablation (MWA) for primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

Seventy five patients (25 males and 50 females; mean age, 56.80 ± 12.34; age range, 26-85) with PHPT undergoing MWA under ultrasound guidance were enrolled between May 2017 and December 2020. The cure rate and complications were evaluated after treatment. The potential factors influencing cure rate of ultrasound-guided MWA for PHPT were analyzed by univariate and multivariate binary logistic regression.

RESULTS

Fifty six of 75 patients had normal PTH and serum calcium levels after at least 6 months after one session MWA, and the cure rate was 74.7% (56/75). 6 uncured patients received the second session MWA during follow-up, and the cure rate achieved 81.3% (61/75) after the second session MWA. Voice changes occurred in 4 patients (5.33%) and recovered within 3 months after ablation without special treatment. Nodule volume was the independent risk factor associated with cure in PHPT patients undergoing MWA, whether after one session (p = 0.0224; odds ratio, 0.67) or the second session MWA (p = 0.0408; odds ratio, 0.74). The cutoff value for nodule volume in predicting the cure was 0.96 cm³ (one session: sensitivity, 76.8%; specificity, 73.7%; the second session: sensitivity, 72.1%; specificity, 71.4%).

CONCLUSION

In conclusion, parathyroid nodule volume was the independent risk factor associated with cure in PHPT patients undergoing MWA.

Evaluation of efficacy of ultrasound-guided microwave ablation in primary hyperparathyroidism

PURPOSE

We aimed to evaluate the clinical efficacy and safety of ultrasonographically (US)-guided percutaneous microwave ablation (MWA) in the treatment of primary hyperparathyroidism (PHPT).

METHODS

A total of 35 patients who received MWA treatment in our hospital between August, 2019 and January, 2021 were retrospectively analyzed. Serum parathyroid hormone (PTH), calcium, phosphorus levels, and improvement in clinical symptoms were recorded before and after MWA. All patients were followed up for 6 months. Paired-sample t-tests and paired sample Wilcoxon signed-rank tests were used to indicate PTH, calcium, and P levels before and after ablation. Postoperative complications were statistically analyzed to evaluate the therapeutic effect of MWA on PHPT patients.

RESULTS

A total of 38 parathyroid nodules in 35 PHPT patients were completely ablated at one time. These results indicated that MWA could effectively destroy parathyroid tissue and decrease the concentrations of PTH, calcium, and phosphorus compared with those before MWA, and the effect was sustained. Moreover, MWA improved clinical symptoms, and improved quality of life of patients. None of patients developed tracheal and esophageal injuries, peripheral hematoma, infection, or other serious complications.

CONCLUSION

US-guided MWA has shown to be an effective and safe approach to treat PHPT patients.

Role of Sonazoid-based contrast-enhanced ultrasonography in the microwave ablation of primary hyperparathyroidism

OBJECTIVES

This study aimed to determine the performance of Sonazoid-based contrast-enhanced ultrasound (CEUS) in the microwave ablation (MWA) of primary hyperparathyroidism (pHPT).

METHODS

Forty patients with pHPT were enrolled and treated with percutaneous ultrasound (US)-guided MWA assisted by CEUS. All patients underwent immediate CEUS examinations following MWA. On post-ablation day 1, patients who did not display a decrease in intact parathyroid hormone (iPTH) levels to the norm were examined by CEUS to evaluate an incomplete ablation. We compared the serum iPTH and calcium levels and the nodule volumes before and after MWA. The complications were evaluated during and after treatment.

RESULTS

Immediately following MWA, CEUS demonstrated complete ablation with all 44 parathyroid nodules. On post-ablation day 1, five nodules in five patients displayed annular enhancement around the ablation zone on CEUS. The average maximum diameters of the nodules and the ablation zone were 1.09 ± 0.28 cm and 1.36 ± 0.23 cm, respectively. An ablation zone larger than the primary lesion (p < 0.05) generated a higher rate of complete ablation. Compared with pre-MWA, serum iPTH and calcium levels were significantly improved. Treatment success was achieved in 38 patients (95%). Hoarseness was a major complication in six patients (15%); however, it improved spontaneously within 1-4 months. We observed two recurrences (2/40, 5%) at 9 months and 11 months following MWA, respectively.

CONCLUSION

US-guided percutaneous MWA assisted by CEUS for pHPT is an effective and safe therapy. CEUS can avoid operative failure and improve the cure rate.

Microwave ablation versus parathyroidectomy for the treatment of primary hyperparathyroidism: a cohort study

OBJECTIVE

To compare the clinical outcomes between microwave ablation (MWA) and parathyroidectomy (PTX) for the treatment of primary hyperparathyroidism (pHPT).

MATERIALS AND METHODS

This retrospective study enrolled 212 patients with pHPT treated by either MWA (MWA group) or PTX (PTX group) from January 2015 to October 2020. The baseline data were balanced through propensity score matching. Clinical cure was evaluated by the Kaplan-Meier method and compared between the MWA and PTX groups. The risk factors related to persistent or recurrent pHPT were screening out using a Cox proportional hazards regression model.

RESULTS

After propensity score matching, a total of 174 patients were enrolled in the present study, with 87 patients in each group. During the follow-up period (median, 28.5 months), there were no differences between the two groups regarding the clinical cure (hazard ratio, 1.71; 95% confidence interval: 0.81-3.62; p = .155), persistent pHPT rate (13.8% vs. 10.3%, p = .643), recurrent pHPT rate (6.9% vs. 3.4%, p = .496), or major complications (6.9% vs. 3.4%, p = .496). MWA resulted in a shorter procedure time (30 min vs. 60 min), smaller incision length (0.1 cm vs. 7 cm) and slightly higher costs (25745 CNY vs. 24111 CNY) (all p < .001). High levels of preoperative intact parathyroid hormone (p = .01) and multiple pHPT nodules (p < .001) were independent risk factors for recurrent and persistent pHPT in the two groups.

CONCLUSION

MWA and PTX have comparable clinical outcomes for pHPT. MWA has a shorter procedure time and smaller incision length.

KEY POINTS

• There were no differences in terms of clinical cure, persistent pHPT, recurrent pHPT, or major complications between MWA and PTX in the treatment of pHPT. • MWA is minimally invasive and results in a shorter procedure time. • Multiple nodules and high levels of iPTH were the independent risk factors for recurrent and persistent pHPT.

Efficacy and Safety of Ultrasound-Guided Radiofrequency Ablation for Primary Hyperparathyroidism: A Prospective Study

Objective

To assess the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) in patients with primary hyperparathyroidism (PHPT).

Materials and Methods

This prospective study enrolled 39 participants (14 male, 25 female; mean age, 59.5 ± 15.3 [range, 18–87] years) between September 1, 2018, and January 31, 2021. All participants had parathyroid lesions causing PHPT, proven biochemically and through imaging. The imaging features of the PHPT nodules, including the shape, margin, size, composition, and location, were evaluated before treatment. Serum intact parathyroid hormone, calcium, and phosphorus levels; parathyroid nodule volume; and PHPT-related symptoms were recorded before and after treatment. We calculated the technical success, biochemical cure, and clinical cure rates for these patients. Complications were evaluated during and after the ablation.

Results

Complete ablation was achieved in 38 of the 39 nodules in the 39 enrolled participants. All the patients were treated in one session. The technical success rate was 97.4% (38/39). The mean follow-up duration was 13.2 ± 4.6 (range, 6.0–24.9) months. At 6 and 12 months post-RFA, the biochemical cure rates were 82.1% (32/39) and 84.4% (27/32), respectively, and the clinical cure rates were 100% (39/39) and 96.9% (31/32), respectively. Only 2.6% (1/39) of the patients had recurrent PHPT. At 1, 3, 6, and 12 months after technically successful RFA, 44.7% (17/38), 34.3% (12/35), 15.8% (6/38), and 12.5% (4/32) of participants, respectively, had elevated eucalcemic parathyroid hormone levels. Recurrent laryngeal nerve paralysis occurred in 5.1% (2/39) of the patients, who recovered spontaneously within 1–3 months.

Conclusion

US-guided RFA was effective and safe for PHPT patients. RFA may be an alternative treatment tool for patients who cannot tolerate or refuse to undergo surgery.

Long-Term Effect of Microwave Ablation on Patients Undergoing Hemodialysis for Moderate Secondary Hyperparathyroidism: A Retrospective Cohort Study

OBJECTIVES

A previous 12-month study confirmed that microwave ablation (MWA) was effective for moderate secondary hyperparathyroidism (SHPT). A further analysis was performed in this study to evaluate the efficacy of MWA for moderate SHPT over an observational follow-up period of up to 60 months.

METHODS

This was a retrospective cohort study of patients involved in a previous randomized controlled trial. Patients were divided into an MWA group (those who underwent MWA followed by drug therapy according to the patient's clinical situation) and a control group (those who received drug therapy only). The primary outcome was the composite endpoint. During the efficacy assessment phase, the two groups were compared in terms of the proportion of patients with intact parathyroid hormone (iPTH) levels <300 pg/ml and the differences in iPTH levels.

RESULTS

Twenty-seven patients were included in this study: 13 in the MWA group and 14 in the control group. The median (interquartile range) follow-up periods of the MWA and control groups were 58 (54-60) and 58 (49-60) months, respectively. The proportion of patients with iPTH levels <300 pg/ml in the MWA group was slightly higher than that in the control group (6/13 [46.2%] versus 2/14 [14.3%], respectively; p = .08). Furthermore, iPTH levels in the MWA group were lower than in the control group during the efficacy assessment phase (411 ± 299 pg/ml versus 516 ± 369 pg/ml, respectively; p <.01).

CONCLUSIONS

MWA helped to contain the necessary iPTH levels in patients undergoing hemodialysis for moderate SHPT in a 60-month timeframe.

Microwave ablation as an efficient therapy for primary hyperparathyroidism: Efficacy and predictors of treatment success

BACKGROUND

Microwave ablation (MWA) has great potential for the treatment of primary hyperparathyroidism, but as predictors and therapeutic efficiency have not been fully clarified, further investigations are required.

AIM

The purpose of this study was to explore the predictors of MWA efficacy in patients with primary hyperparathyroidism (PHPT) induced by parathyroid adenoma.

METHODS

The study included patients with PHPT treated with MWA separated into two groups as response and no response group, according to the efficacy of the treatment. The two groups were compared with respect of possible predictors, such as age, gender, parathyroid adenoma volume, baseline levels of calcium (Ca), phosphorous (P), alkaline phosphate (ALP) and vitamin D, localisation of parathyroid adenoma, and instrumental parameters such as microwave ablation time and power. The statistical significance of possible predictors of MWA efficacy was investigated by using logistic regression analysis.

RESULTS

Evaluation was made of 32 patients in respect of analysing predictors of MWA efficacy. In the comparison of the values of the response and no response groups, only baseline Ca level was determined to be a potential predictor of the efficacy of MWA (P < .05). Further logistic regression results showed the baseline Ca level to be insignificant for the construction of a mathematical model to predict the efficacy of MWA (P = .071). The clinical success rate was 87.5%. Compared with pre-MWA, the serum PTH, calcium, phosphorus and ALP levels were significantly improved at 6 months post-MWA (PTH, 99 (86-154) ng/L vs 50 (46-58) ng/L; calcium, 2.94 (2.81-2.98) mmol/L vs 2.38 (2.28-2.50) mmol/L; phosphorus, 0.87 (0.82-1.01) mmol/L vs 1.16 (1.0-1.3) mmol/L; ALP, 82 (73-98) U/L vs 69 (54-84) U/L, respectively; all, P < .01.

CONCLUSIONS

Although no predictor of treatment success could be determined, MWA might be an effective treatment in patients with PHPT.

Effectiveness and Safety of Thermal Ablation in the Treatment of Primary Hyperparathyroidism: A Multicenter Study

CONTEXT

Ultrasound (US)-guided thermal ablation has generated recent interest as minimally invasive treatments of primary hyperparathyroidism (pHPT). But definitive evidence for the efficacy of thermal ablation in treating pHPT is not well characterized.

OBJECTIVE

This work aims to evaluate the effectiveness and safety of thermal ablation for pHPT.

METHODS

From January 2015 to March 2020, data pertaining to patients who received thermal ablation for pHPT at 4 centers were retrospectively analyzed. The median follow-up duration was 18.1 months (interquartile range, 6.5-42.2 months). A cure referred to the reestablishment of normal values of serum calcium and intact parathyroid hormone throughout the entire follow-up period, at least more than 6 months. The technical success, effectiveness, and safety of treatment were analyzed.

RESULTS

A total of 119 patients (mean age, 57.2 ± 16.3 years; 81 female) with 134 parathyroid nodules were enrolled. The mean maximum diameter of the parathyroid glands was 1.6 ± 0.9 cm. Ninety-six patients underwent microwave ablation (MWA), and 23 patients underwent radiofrequency ablation (RFA). The technical success rate was 98.3% and the cure rate was 89.9%. Significant differences were found in the maximum diameter between the cured patients and the patients who did not undergo ablation of the target lesions. Except for cases with pHPT nodules less than 0.6 cm in diameter, the cure rate was 95%. There were no difference in cure rates at 6 months between the MWA and RFA groups (MWA vs RFA, 90.6% vs 87.0%; χ 2 = 0.275, P = .699). The volume reduction rate of the ablation zone was 94.6% at 12 months. The complication rate was 6.7% (8/119). With the exception of one patient with persistent voice impairment, other symptoms spontaneously resolved within 6 months.

CONCLUSION

Thermal ablation is effective and safe for pHPT.

Microwave ablation versus radiofrequency ablation for primary hyperparathyroidism: a multicenter retrospective study

OBJECTIVE

To compare the clinical outcomes of microwave ablation (MWA) and radiofrequency ablation (RFA) in the treatment of primary hyperparathyroidism (pHPT).

METHOD

This retrospective study included 104 pHPT patients treated by MWA or RFA between January 2015 and March 2020 in four centers. The clinical outcomes including effectiveness and complications were compared between the two groups. Ablation cure was defined as the reestablishment of normal values of serum calcium and intact parathyroid hormone (iPTH) at least more than 6 months. Clinical cure was defined as the reestablishment of normal values of serum calcium and iPTH throughout the entire follow-up period.

RESULTS

A total of 77 patients underwent MWA (mean age, 55.5 ± 16.4 years) and 27 underwent RFA (mean age, 58.9 ± 15.6 years). During the follow-up (median, 18.7 months in the MWA group; 12 months in the RFA group), no difference was observed between ablation cure rates (88.3% vs. 88.9%, p = 1.000), clinical cure rates (87.0% vs. 82.3%, p = .880), recurrent pHPT (5.2% vs. 3.7%, p = .447), persistent pHPT (11.7% vs. 11.1%, p = 1.000) and complication rate (9.1% vs. 3.7%, p = .677). A maximum diameter less than 0.7 cm was an independent prognostic factor of uncured pHPT in ablation (hazard ratio, 0.1; 95% confidence interval: 0.02, 0.54; p = .007). Major complication - voice change encountered in five patients (6.5%) in the MWA group and in one patient (3.7%) in the RFA group.

CONCLUSION

Both RFA and MWA are safe and effective techniques for patients with pHPT, with comparable clinical outcomes.

Ultrasound-guided radiofrequency ablation for the treatment of primary hyperparathyroidism: An efficacy and safety study

OBJECTIVE

To evaluate the efficacy and safety of radiofrequency ablation (RFA) for the treatment of primary hyperparathyroidism (pHPT).

METHODS

25 patients who were treated with RFA for pHPT from September 2015 to January 2020 were enrolled in our study. The serum intact parathyroid hormone (iPTH), calcium and phosphate levels were tested within 1 week before RFA and at 1 day, 1 month, 3months, 6months and 12months after ablation. The ablation areas were evaluated by US at 1, 3, 6 and 12 months after RFA. Postoperative complications including voice hoarseness, hematoma, postoperative pain, incision infections, hypoparathyroidism and hypocalcemia were recorded.

RESULTS

A total of 25 pHPT patients (53.9 ± 10.9 years, 22 women and 3 men) with 29 enlarged parathyroid glands were treated by RFA. 22 of them were treated in one session and the other three were treated in two sessions. Serum iPTH and calcium levels decreased significantly at 1 day after RFA (all P < 0.05). 21 patients had normal levels of serum iPTH and calcium after RFA, with a cure rate of 84%. 26 treated parathyroid glands exhibited a volume reduction rate greater than 70% at the 12 months follow-up. There were only some minor complications, including four postoperative pain (4/25, 16%) and one mild postoperative transient hypocalcemia (1/25, 4%).

CONCLUSIONS

US-guided RFA is an effective and safe technique for the treatment of carefully selected patients with pHPT. Larger sample size and longer follow-up are still need to further confirm its clinical value.

[Normocalcemic with elevated post-operative parathormone in primary hyperpara-thyroidism: 9 case reports and literature review]

OBJECTIVE

To summarize and analyze the clinical characteristics of primary hyperpara-thyroidism (PHPT) with normocalcemic parathormone elevation (NPE) after surgical treatment, so as to improve the therapeutic ability and standardized post-operative follow-up of PHPT patients.

METHODS

Nine patients who were diagnosed with PHPT in the Department of Endocrinology of China-Japan Friendship Hospital from August 2017 to November 2019 were selected as the subjects. They all developed NPE within 6 months after surgical treatment. The clinical features and outcomes were collected and analyzed retrospectively, in addition, the related literature was reviewed.

RESULTS

Clinical features: among the 9 patients, 6 were middle-aged and elderly females and 3 were male. The main clinical manifestations were bone pain, kidney stones, nausea and fatigue except for one case of asymptomatic PHPT. Pre-operative examination showed high serum calcium [(3.33±0.48) mmol/L], low serum phosphorus [0.76 (0.74, 0.78) mmol/L], high 24-hour urinary calcium [8.1(7.8, 12.0) mmol/24 h], obviously elevated intact PTH [(546.1±257.7) ng/L], vitamin D deficiency [25-hydroxyvitamin D₃ (21.0±5.7) nmol/L]. Serum levels of bone alkaline phosphatase [7 patients 41.3(38.6, 68.4) μg/L, 2 patients >90 μg/L] and N-terminal midcourse osteocalcin (>71.4 μg/L) were significantly elevated. The estimated glomerular filtration rate decreased in 2 patients. Imaging examination: 7 patients had osteoporosis. Renal calculi were found in 3 patients by renal ultrasound. Imaging examination of parathyroid glands found definite lesions in all the patients, including 2 cases of multiple lesions and 7 cases of single lesions.

TREATMENT AND OUTCOME

two patients underwent parathyroidectomy, while other patients were treated with microwave thermal ablation. PTH increased 1 month after therapy [(255.0±101.4) ng/L], and no recurrent lesions were found by parathyroid ultrasound. After combined treatment with cal-cium and vitamin D for six months, PTH decreased significantly and the level of serum calcium remained normal at anytime during the follow-up period.

CONCLUSION

The occurrence of postoperative NPE may be related to the higher pre-operative PTH, vitamin D deficiency and lower creatinine clearance. However, NPE may not predict recurrent hyperthyroidism or incomplete parathyroidectomy. Adequate calcium and vitamin D supplementation after surgery seems to be beneficial for patients with NPE. Post-operative follow-up of PHPT patients should be standardized to prevent and treat post-operative NPE.

A study on the causes of operative failures after microwave ablation for primary hyperparathyroidism

Objective

To summarize the occurrence of operative failures after microwave ablation (MWA) in patients with primary hyperparathyroidism (pHPT), analyze the possible reasons, and explore strategies for preventing and managing these situations.

Methods

This retrospective study reviewed 91 pHPT patients who underwent MWA from April 2015 to November 2019. A cure was defined as the reestablishment of normal calcium homeostasis lasting a minimum of 6 months. An operative failure was defined as a failure to normalize serum intact parathyroid hormone (iPTH) and/or calcium levels at 6 months or longer. Patients who encountered operative failures were compared with patients who were successfully cured.

Results

Eighty-eight pHPT patients, consisting of 29 men and 59 women, were finally enrolled. The median follow-up duration was 15.9 months (IQR, 6.1–31.5 months). Seventy-eight patients (78/88, 88.6%) were cured. Ten (10/88, 11.4%) patients experienced operative failure, including 9 persistent pHPT (10.2%) and 1 (1.1%) recurrent pHPT. Small parathyroid nodules (maximum diameter < 0.6 cm) and incomplete ablation were the two key factors leading to operative failure. Of the 9 patients with a maximum nodule diameter less than 0.6 cm, 77.8% (7/9) of them encountered operative failure.

Conclusion

Operative failure occurred in 11.4% of the pHPT patients who underwent MWA. The possibility of operative failure was increased when the maximum diameter of parathyroid nodule was less than 0.6 cm. Complete ablation could help avoid operative failure.

Key Points

• Failed to ablate the target lesion and incomplete ablation were the key factors attributed to operative failures.

• When the maximum diameter of the parathyroid nodules is less than 0.6 cm, the possibility of operative failure was higher.

Two-year changes of biochemical profiles and bone mineral density after percutaneous ultrasound-guided microwave ablation for primary hyperparathyroidism

PURPOSE

To investigate the changes of the serum parathyroid hormone (PTH) and calcium level, as well as bone mineral density (BMD), after percutaneous ultrasound-guided microwave ablation (MWA) for primary hyperparathyroidism (pHPT) caused by single hyperfunctional nodule.

METHODS

The study enrolled 20 patients with a total of 20 nodules of MWA treatment to pHPT in one session. The normalization rate of the serum PTH and calcium was evaluated at every 6 months during 2-year follow-up after MWA. The bone mineral density (BMD) at lumbar spine and femoral neck were also compared before and after the procedure.

RESULTS

The normalization rate of both PTH and serum calcium at 6-, 12-, 24-month follow-up was 66.6%, 80.0%, and 62.5%, respectively. Though the normalization rate of serum calcium level at 6-, 12-, and 24-month visit after MWA was 100%. The BMD increased 12, 24 months after MWA at lumbar spine (1.022 ± 0.155, 1.057 ± 0.151 vs 0.965 ± 0.145 g/cm², p < 0.01) and femoral neck at 2-year assessment (0.819 ± 0.094 vs 0.771 ± 0.102 g/cm², p = 0.015). Seven nodules disappeared in 20 nodules (35.0%), average ablation time was 122.29 ± 107.54 s (34-460 s). Six patients encountered voice change during the procedure, one participant was confirmed recurrent laryngeal injuries but recovered within 2 months.

CONCLUSIONS

Percutaneous ultrasound-guided microwave ablation results in improvement of biochemical profiles and bone mineral density in subjects with single hyperfunctional parathyroid nodule. However, the long-term efficacy of the MWA remains to be verified.

Bone Turnover Markers in Response to Ultrasound-Guided Microwave Ablation for Primary Hyperparathyroidism

OBJECTIVE

To assess the efficacy and safety of ultrasound-guided microwave ablation (MWA) in the treatment of primary hyperparathyroidism (PHPT), and to investigate whether MWA can improve the bone turnover and renal function.

METHODS

A total of 20 consecutive PHPT patients with 21 parathyroid lesions treated with MWA in our center from May 2019 to March 2021 were recruited in this study. Serum parathyroid hormone (PTH), calcium and phosphorus levels before MWA and at 20 minutes, 4 hours, 1 day, 3 months, 6 months and 12 months after MWA were measured. Bone turnover biomarkers, renal function and lesion volume with volume reduction rate (VRR) before MWA and at the last follow-up were compared. Any complication related with MWA was evaluated. The technical and clinical success rates of MWA in the treatment of PHPT were calculated. Clinical success was defined as normal serum PTH and calcium without PHPT-associated manifestations at more than 6 months after ablation. Technical success was defined as complete ablation indicated by immediate postoperative contrast-enhanced ultrasound.

RESULTS

The serum PTH, calcium and phosphorus levels at their respective follow-up time points dropped significantly after MWA (P <0.05). The volume of parathyroid lesions at the final examination was significantly reduced, compared with pre-ablation volume (P <0.001), with a median VRR reaching 89%. The technical and clinical success rates were 100% and 63.6%, respectively. Substantial changes of bone turnover biomarkers were observed before and after MWA (P <0.05), but the differences in renal function were not statistically significant. No major complications were reported in all cases. Pre-MWA serum PTH, lesion volume, maximum diameter of lesion and ablation time were significantly different between patients with successful and failed MWA.

CONCLUSIONS

PHPT can be effectively and safely treated by ultrasound-guided MWA, as proven by drop in serum PTH and reduction in the volume of parathyroid adenomas. Besides, MWA can impede bone remodeling to suppress hyperparathyroidism in the condition of PHPT.

Comparison of microwave ablation treatments in patients with renal secondary and primary hyperparathyroidism

Purpose

Microwave ablation (MWA) is feasible for severe renal secondary hyperparathyroidism (SHPT) and primary hyperparathyroidism (PHPT) patients ineligible for parathyroidectomy (PTX). Here we compared the clinical manifestations and characteristics of parathyroid glands in these two groups, and summarized the techniques, safety and efficacy of MWA.

Methods

Baseline clinical characteristics, ablation-related techniques, adverse events/complications, and efficacy were recorded.

Results

In SHPT group, malnutrition, cardiovascular/pulmonary complications, and abnormal bone metabolism were severe. SHPT patients had more hyperplastic parathyroid glands. The volume of each gland was smaller, and the time of ablation for a single parathyroid was shorter in the SHPT group, although there were no significant differences compared with patients in the PHPT group. Three patients in both groups had recurrent laryngeal nerve injuries and all recovered, except for one SHPT patient. By the end of follow-up, serum iPTH levels had decreased from 2400.26 ± 844.26 pg/mL to 429.39 ± 407.93 pg/mL (p < .01) in SHPT and from 297.73 ± 295.32 pg/mL to 72.22 ± 36.51 pg/mL in PHPT group (p < .01). Hypocalcemia was more common (p < .001) and serum iPTH levels were prone to rebound in SHPT patients after MWA.

Conclusion

MWA can be reserved for those who had high surgical risks because of less invasiveness. Injuries of recurrent laryngeal nerves should be noticed. The health status, perioperative, and intraoperative procedures were more complicated and all parathyroids found by ultrasound should be ablated completely in SHPT patients.

Efficacy and safety of US-guided thermal ablation for primary hyperparathyroidism: a systematic review and meta-analysis

Purpose: To summarize the published literature on thermal ablation for primary hyperparathyroidism (PHPT) and to evaluate the effectiveness and safety of thermal ablation as a novel treatment strategy.Materials and methods: Two authors carried out the literature search using four databases independently, including PubMed, Embase, Cochrane, and Web of Science. The meta-analysis included prospective and retrospective data that compared post-ablative outcomes to pre-ablative values. The primary outcomes were parathyroid hormone (PTH), serum calcium and volume of the parathyroid gland (VPG).Results: From the 184 original articles, five studies (4 retrospective studies and 1 prospective study) examining 84 patients met the inclusion criteria. The meta-analysis showed significant reduction of PTH at 3 (standardized mean difference (SMD) =  -1.09, 95% confidence index (CI) =  -1.42 to -0.76, p < 0.001) and 6 months (SMD =  -1.13, 95% CI =  -1.46 to -0.80, p < 0.001) after thermal ablation. Serum calcium level was significantly reduced at 3 (mean difference (MD) =  -0.31, 95% CI =  -0.50 to -0.12, p  =  0.001) and 6 months (MD =  -0.31, 95% CI =  -0.46 to -0.17, p < 0.001) after thermal ablation. There was no significant difference between pre-ablative VPG and that of 6 months after ablation (MD =  -0.30, 95% CI =  -0.70 to 0.09, p  =  0.13). The most common complications were transient dysphonia and subcutaneous edema. No major complications or death occurred.Conclusion: Thermal ablation is effective and safe for treatment of PHPT. PTH and calcium levels were reduced significantly at 3 and 6 months after thermal ablation.

Clinical Study on Safety and Efficacy of Microwave Ablation for Primary Hyperparathyroidism

Objective

To evaluate the safety, feasibility, and efficacy of microwave ablation (MWA) for the treatment of primary hyperparathyroidism (PHPT).

Materials and Methods

This study enrolled 67 PHPT patients (22 men, 45 women; mean age, 56.0 ± 16.3 years; range, 18–83 years) from January 2015 to December 2018. The laboratory data, including the serum intact parathyroid hormone (iPTH), calcium, phosphorus, and alkaline phosphatase (ALP) levels, were evaluated before MWA and again 2 hours, 1 day, 7 days, 1 month, 3 months, 6 months, 12 months, 18 months, and 24 months after.

Results

Complete ablation was achieved with all 72 hyperplastic parathyroid glands found on the 67 patients enrolled, 64 of whom were treated in one session and 3 were treated over two sessions. The technical success rate was 100%. The median follow-up time was 13.6 months (range, 10.0–31.1 months). The clinical success rate was 89.4%. The volume reduction rate was 79.4% at 6 months. Compared to pre-MWA, the serum iPTH, calcium, phosphorus, and ALP levels had significantly improved 6 months post-MWA (iPTH, 157.3 pg/mL vs. 39.2 pg/mL; calcium, 2.75 ± 0.25 mmol/L vs. 2.34 ± 0.15 mmol/L; phosphorus, 0.86 ± 0.20 mmol/L vs. 1.12 ± 0.22 mmol/L; ALP, 79 U/L vs. 54 U/L, respectively; all, p < 0.01). Hoarseness was a major complication in 4 patients (6.0%), but it improved spontaneously within 2–3 months.

Conclusion

MWA is safe, feasible, and effective for the treatment of PHPT.

Minimally Invasive Treatment for Benign Parathyroid Lesions: Treatment Efficacy and Safety Based on Nodule Characteristics

OBJECTIVE

This study aimed to evaluate the efficacy and safety of ultrasound (US)-guided minimally invasive treatment in patients with parathyroid lesions.

MATERIALS AND METHODS

This study included 27 patients who had undergone US-guided radiofrequency ablation (RFA) or ethanol ablation (EA) for parathyroid lesions between January 2010 and 2018. RFA was performed in 19 patients with primary hyperparathyroidism (PHPT, n = 11) or secondary hyperparathyroidism (SHPT, n = 8), and EA was performed in eight patients with symptomatic nonfunctioning parathyroid cysts (SNPCs). Nodule size, volume, serum parathyroid hormone (PTH) and calcium levels were recorded before and after treatment. Complications were evaluated during and after treatment.

RESULTS

In patients with PHPT, significant reductions in size and volume were noted after RFA at 6- and 12-month follow-up (all, p < 0.05). Seven nodules nearly completely disappeared (residual volume < 0.1 mL); serum PTH and calcium levels were reduced to normal ranges (7/11, 63.6%). Four patients experienced partial reductions of serum PTH and calcium levels (4/11, 36.4%). In patients with SHPT, three experienced therapeutic response of serum PTH (3/8, 37.5%), while five showed persistent hyperparathyroidism (5/8, 62.5%) within 6 months after RFA. In patients with SNPCs, EA resulted in significant reductions in cyst size and volume (all, p < 0.05) at the last follow-up. A total of four complications (two transient hypocalcemia [RFA], one permanent [RFA], and one transient [EA] hoarseness) were observed.

CONCLUSION

Minimally invasive treatments, such as RFA and EA, may serve as therapeutic alternatives for patients with PHPT or SNPCs; they may have limited usefulness in patients with SHPT.