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

Radiofrequency Ablation of Parathyroid Adenoma: Results of a Retrospective Analysis of 60 Patients

PURPOSE

To present the effectiveness and safety of radiofrequency ablation (RFA) in parathyroid adenoma (PTA).

MATERIALS AND METHODS

In this retrospective study, 60 patients with a single PTA were evaluated for changes in biochemical and ultrasonographic features up to 6 months after RFA of the lesion. Adenomas were ablated with an alternative technique so called "Nik jet dissection" which incorporates full hydrodissection and polar artery coagulation. Complications as well as the variations in biochemical data and nodule volumes were analyzed between baseline measurements and at each follow-up interval data (first day, 1, 3, and 6 months after ablation) were analyzed.

RESULTS

A significant reduction in serum intact parathyroid hormone and calcium levels was observed 6 months after ablation, with a mean difference of - 83.4 ± 104.1 pg/mL, p < 0.001, and - 0.29 ± 0.22 mmol/L, p < 0.001, respectively. Serum phosphorus levels increased significantly with a mean difference of 0.09 ± 0.19 mmol/L, p = 0.040 at the end of the follow up. We observed a significant volume reduction rate of parathyroid adenomas with 89 ± 20.8 percent, p < 0.001. Also, 51% of adenomas disappeared at the end of the follow up. In this study, two cases of hematoma and one case of transient hoarseness (grade 1 of the CIRSE classification) were encountered.

CONCLUSION

Our study showed that RFA with the alternative technique, called "Nik jet dissection" is a safe and effective modality in management of PTA. Therefore, we suggest expanding the indications for RFA in PTA management, especially when surgery is not feasible.

LEVEL OF EVIDENCE

Level 3, Local non-random sample.

Radiofrequency ablation for patients with recurrent or persistent secondary hyperparathyroidism after parathyroidectomy: initial experience

BACKGROUND

Reoperation for recurrent or persistent secondary hyperparathyroidism (SHPT) after parathyroidectomy is challenging due to surgical scars and postoperative adhesions. Therefore, there is an increasing need to develop a new minimally invasive therapy.

OBJECTIVE

To analyze the efficacy of ultrasound (US)-guided radiofrequency ablation (RFA) in patients with recurrent or persistent SHPT after parathyroidectomy.

PATIENTS AND METHODS

From March 2013 to January 2022, 20 enlarged parathyroid glands in 10 patients with recurrent or persistent SHPT were treated with US-guided RFA. The levels of serum intact parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP), as well as clinical symptoms, were compared before and after RFA. The ablation procedure-related complications were also evaluated. The target range for iPTH levels was approximately 2-9 times the upper limit of normal (130-585 pg/mL).

RESULTS

The mean follow-up time was 49.6 ± 34.5 months (range from 6 to101 months). The levels of serum iPTH, Ca, and P decreased significantly one day post-ablation. Six months after RFA, 70% of patients reached the targets for iPTH, and 50% of patients reached targets at the end of follow-up. Two patients underwent repeat ablation at 9 months and 6 years after RFA, respectively, due to persistently elevated iPTH levels, and both had serum iPTH concentrations in the recommended range at the recent follow-up visit. The patients' clinical symptoms significantly improved after ablation. Major complications after RFA included hoarseness (2/10) and permanent hypoparathyroidism (1/10). Severe hypocalcemia occurred in four patients (4/10) after ablation.

CONCLUSION

US-guided percutaneous RFA for recurrent or persistent SHPT is safe, efficacious, and repeatable, and can significantly improve hyperparathyroidism-related symptoms.

Complications of microwave ablation in patients with persistent/recurrent hyperparathyroidism after surgical or ablative treatment

OBJECTIVE

To evaluate the complications associated with microwave ablation (MWA) in treating persistent/recurrent hyperparathyroidism (HPT) post-surgical or ablative treatments.

MATERIALS AND METHODS

From January 2015 to December 2022, 87 persistent/recurrent HPT patients (primary HPT [PHPT]: secondary HPT [SHPT] = 13:74) who underwent MWA after surgical or ablative treatment were studied. Grouping was based on ablation order (initial vs. re-MWA), prior treatment (parathyroidectomy [PTX] vs. MWA), and etiology (PHPT vs. SHPT). The study focused on documenting and comparing treatment complications and analyzing major complication risk factors.

RESULT

Among the 87 patients, the overall complication rate was 17.6% (15/87), with major complications at 13.8% (12/87) and minor complications at 3.4% (3/87). Major complications included recurrent laryngeal nerve (RLN) palsy (12.6%) and Horner syndrome (1.1%), while minor complications were limited to hematoma (3.4%). Severe hypocalcemia noted in 21.6% of SHPT patients. No significant differences in major complication rates were observed between initial and re-MWA groups (10.7% vs. 13.8%, p = 0.455), PTX and MWA groups (12.5% vs. 15.4%, p = 0.770), or PHPT and SHPT groups (15.4% vs. 13.5%, p > 0.999). Risk factors for RLN palsy included ablation of superior and large parathyroid glands (>1.7 cm). All patients recovered spontaneously except for one with permanent RLN palsy in the PTX group (2.1%).

CONCLUSION

Complication rates for MWA post-surgical or ablative treatments were comparable to initial MWA rates. Most complications were transient, indicating MWA as a viable and safe treatment option for persistent/recurrent HPT patients.

Radiofrequency ablation as a treatment modality for primary hyperparathyroidism: a systematic literature review

Background

Primary hyperparathyroidism (pHPT) is an endocrine disorder typically characterized by elevated serum calcium and elevated parathyroid hormone (PTH). While parathyroidectomy is the standard treatment, non-operative intervention such as radiofrequency ablation (RFA) has been adopted as an alternative for the management of pHPT, as it has been utilized in other endocrine glands such as thyroid and adrenal. In this literature review, we aim to evaluate the current practice of RFA for pHPT.

Methods

A systematic literature search using PubMed, Web of Science, and Embase through June 2022 was conducted. Studies included in the review consisted of patient cohorts who had an unequivocal diagnosis of pHPT and underwent the treatment of pHPT with RFA. When more than one study was published from a similar cohort of patients, only the study with the most number of patients was considered. Studies included were assessed for bias using the critical appraisal instruments from the Joanna Briggs Institute (JBI) System.

Results

A total of 14 studies describing 167 parathyroid glands treated in 163 patients were reviewed. The overall cure rate was 91.2%, with 5 patients undergoing more than one ablation. The most common adverse effect encountered was temporary dysphonia. Incomplete ablation and missed multiglandular disease were the most common reasons for RFA treatment failure.

Conclusions

RFA may be an effective and safe alternative to parathyroidectomy in select patients with a well-localized, well-located parathyroid adenoma. Additional long-term data are needed to refine its role in the pHPT treatment algorithm.

Effectiveness and safety of the radiofrequency ablation of single hyperfunctioning parathyroid lesions suggestive of adenomas in primary hyperparathyroidism

INTRODUCTION

Radiofrequency ablation (RFA) has emerged as a minimally invasive approach to single parathyroid adenoma in primary hyperparathyroidism; however, there is limited evidence on its effectiveness.

OBJECTIVE

To evaluate the effectiveness and safety of RFA to treat hyper-functioning parathyroid lesions suggestive of adenomas.

MATERIAL AND METHODS

A prospective study was conducted in consecutive patients with primary hyperparathyroidism treated with RFA for single parathyroid lesions in our reference center between November 2017 and June 2021. Pre-treatment (baseline) and follow-up analytical data were gathered on total protein-adjusted calcium, parathyroid hormone [PTH], phosphorus, and 24-h urine calcium. Effectiveness was defined as complete response (normal calcium and PTH), partial response (reduced but not normalized PTH with normal serum calcium), or disease persistence (elevated calcium and PTH). SPSS 15.0 was used for statistical analysis.

RESULTS

Four of thirty-three enrolled patients were lost to the follow-up. The final sample comprised 29 patients (22 females) with mean age of 60.93 ± 13.28 years followed up for a mean of 16.29 ± 7.23 months. Complete response was observed in 48.27%, partial response in 37.93%, and hyperparathyroidism persistence in 13.79%. Serum calcium and PTH levels were significantly lower at 1 and 2 years of post-treatment than at baseline. Adverse effects were mild, with two cases of dysphonia (self-limited in one patient) and no cases of hypocalcaemia or hypoparathyroidism.

CONCLUSION

RFA may be a safe and effective technique to treat hyper-functioning parathyroid lesions in selected patients.

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.

Expert consensus on multidisciplinary approach to the diagnosis and treatment of primary hyperparathyroidism in pregnancy in China

Primary hyperparathyroidism in pregnancy is a rare disease that can have detrimental effects on both maternal and fetal/neonatal outcomes. The physiological changes that occur during pregnancy can complicate the diagnosis, imaging examinations, and treatment of this disorder. To enhance our understanding and management of primary hyperparathyroidism in pregnancy, experts from various fields, including endocrinology, obstetrics, surgery, ultrasonography, nuclear medicine, pediatrics, nephrology, and general practice in China, collaborated to develop a consensus addressing the critical aspects of the diagnosis and treatment of primary hyperparathyroidism in pregnancy with a multidisciplinary team approach. This consensus provides valuable guidance for healthcare professionals in managing this condition, ultimately improving outcomes for both mothers and their babies.

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 ablation in the treatment of recurrent primary hyperparathyroidism in a patient with MEN1: a case report

Background

Multiple endocrine neoplasia type 1 (MEN1) is an inherited endocrine syndrome caused by the mutation in the tumor suppressor gene MEN1. The recurrence rate of primary hyperparathyroidism (PHPT) in patients with MEN1 after parathyroidectomy remains high, and the management of recurrent hyperparathyroidism is still challenging.

Case presentation

We reported a 44-year-old woman with MEN1 combined with PHPT who was diagnosed through genetic screening of the patient and her family members. After parathyroidectomy to remove one parathyroid gland, the patient suffered from persistent high levels of serum calcium and parathyroid hormone, which returned to normal at up to 8 months after ultrasound-guided microwave ablation (MWA) for bilateral parathyroid glands, suggesting an acceptable short-term prognosis.

Conclusion

Ultrasound-guided MWA for parathyroid nodules may be an effective therapeutic strategy for recurrent PHPT in MEN1 patients.

Persistent and Recurrent Primary Hyperparathyroidism: Intraoperative Supplemental Methods, Basic Principles of Surgery, and Other Treatment Options

Reoperative parathyroid surgery is challenging even for experienced surgeons. Cure rates are lower than primary surgery. Good anatomical and embryological knowledge is important. Preoperatively, a comprehensive surgical strategy should be planned. Pre-operative imaging modalities should be used extensively to find the overlooked gland to have a possibility to perform focused parathyroid surgery to avoid possible complications. One of the important developments is the new ancillary methods to find overlooked parathyroid glands. Orthotopic and possible ectopic locations should be known well by the surgeon to increase the surgical success rate. Reoperative parathyroid surgery needs a distinctive approach compared to primary parathyroid surgery. Basic principles include the selection of the incision and route for entering the thyroid region, use of ancillary methods, and intraoperative nerve monitoring and also require a meticulous dissection. Obtaining a surgical cure is difficult and high surgical caution is needed. Post-operative complication rates are higher compared to primary parathyroid surgery. Other treatment methods and medical treatment options may be evaluated in a patient who cannot undergo surgery.

Radiofrequency ablation of an intrathyroidal parathyroid adenoma with intraoperative parathyroid hormone monitoring: a case report of a novel technique

Background

Primary hyperparathyroidism (PHPT) is classically treated by conventional parathyroidectomy, an open neck surgery. Radiofrequency ablation (RFA) has been shown as a safe minimally-invasive alternative to parathyroidectomy for the management of PHPT and has been shown to be effective in 60-90% of cases. Here, we present a patient successfully treated for persistent PHPT by RFA with simultaneous intraoperative parathyroid hormone (IOPTH) monitoring.

Case Description

A 51-year-old female with a past medical history of resistant hypertension, hyperlipidemia, and vitamin D deficiency presented to our endocrine surgery clinic with PHPT. Neck ultrasound (US) localized a 0.79 cm lesion suggestive of a parathyroid adenoma. Parathyroid exploration resulted in the excision of two masses. IOPTH levels dropped from 259.9 to 204.7 pg/mL. No ectopic parathyroid tissue was found. Three-month follow-up demonstrated elevated calcium levels, suggesting persistent disease. A repeat neck US one-year post operation localized a suspicious hypoechoic sub-centimeter thyroid nodule, which was subsequently determined to be an intrathyroidal parathyroid adenoma. The patient elected to proceed with RFA with IOPTH monitoring, citing concern for increased risk of redo open neck surgery. Operation pursued without complication and IOPTH levels dropped from 270 to 39.1 pg/mL. The patient's only three-day post-operative complaints, occasional numbness and tingling, were completely resolved by her three-month follow up. The patient had normal PTH and calcium levels at seven months post-operation visit and was without complaint.

Conclusions

To our best knowledge, this is the first reported case of RFA with IOPTH monitoring used to manage a parathyroid adenoma. Our work adds to the growing literature suggesting minimally-invasive techniques, such as RFA with IOPTH, as a potential management option for treating parathyroid adenomas.

[Ultrasound-guided anhydrous ethanol and microwave ablation for functional parathyroid cyst: a case report]

We report a case of functional parathyroid cyst treated by ultrasound-guided anhydrous ethanol sclerotherapy and microwave ablation. The 63-year-old female patient was diagnosed to have functional parathyroid cyst with hypercalcemia, high PTH and cystic space-occupying lesions in the neck by ultrasound, radionuclide scanning and PTH measurement of the cystic fluid. The patient refused to receive cyst resection, and anhydrous ethanol sclerotherapy with microwave ablation was performed under ultrasound guidance. The procedure was completed smoothly without any complications either during or after the operation. Follow-up examination of the patient at 18 months after the operation showed a significant reduction of the mass and normal blood calcium and iPTH levels, demonstrating a clinical cure of the patient. Ablative treatment of functional parathyroid cyst has not been documented so far. This approach provides a minimally invasive treatment modality for such cases where surgical resection is not an option, but its efficacy and safety need to be evaluated in more cases with longer follow-up time.

Localization Strategy Prior to Radiofrequency Ablation for Primary and Secondary Hyperparathyroidism

Objective: Preoperative localization in patients with primary or secondary hyperparathyroidism before radiofrequency ablation (RFA) is crucial. There is currently a lack of consensus regarding imaging protocol. Evaluating the diagnostic performance of ultrasound, four-dimensional computed tomography (4D-CT), and technetium 99m-sestamibi single-photon-emission-computed tomography/computed tomography (SPECT/CT) is necessary for RFA of hyperparathyroidism. Methods: This retrospective study recruited patients with primary or secondary hyperparathyroidism who underwent ultrasound, 4D-CT, and SPECT/CT before RFA at a single institution. The sensitivity, accuracy, and receiver operating characteristic curve analysis were used to evaluate the diagnostic performance of the imaging modalities. Results: A total of 33 patients underwent RFA for hyperparathyroidism (8 patients with primary hyperparathyroidism, 25 patients with secondary hyperparathyroidism). Ultrasound had the highest sensitivity (0.953) and accuracy (0.943), while 4D-CT had higher sensitivity and accuracy than SPECT/CT (sensitivity/accuracy, 4D-CT vs. SPECT/CT: 0.929/0.920 vs. 0.741/0.716). Combined ultrasound with 4D-CT and the three combined modalities achieved equivalent, and the highest, diagnostic performance (sensitivity 1.000, accuracy 0.989). The lesion length and volume were important predictors of the diagnostic performance of 4D-CT and SPECT/CT (area under curve of length in 4D-CT/volume in 4D-CT/length in SPECT/volume in SPECT: 0.895/0.834/0.767/0.761). Conclusion: Combined ultrasound with 4D-CT provides optimal preoperative localization prior to RFA in patients with primary or secondary hyperparathyroidism. The length and volume of parathyroid lesions are determinative of the diagnostic performance of 4D-CT and SPECT/CT.

Combination Therapy of Ethanol Ablation and Radiofrequency Ablation to Treat Parathyroid Adenoma in a Case with Primary Hyperparathyroidism

Introduction: Ethanol ablation (EA) and radiofrequency ablation (RFA) are minimal invasive therapeutic modalities to treat primary hyperparathyroidism (PHPT). Case Presentation: A 77-year-old man presented a 3.5-cm parathyroid adenoma with mixed cystic and solid components. He was ineligible for parathyroidectomy because of his age and the surgical history of the coronary artery bypass graft. First, EA was performed to remove cystic component. After that, the volume of parathyroid adenoma was decreased (volume reduction rate: 94%); however, the level of serum parathyroid hormone (PTH) was persistently high (88 pg/mL). Subsequent RFA was performed to remove the remaining parathyroid adenoma. Further, it was completely disappeared on the following ultrasound examination, and PTH was normalized. The results during a 2-year follow-up confirmed clinical success, and no relevant complication was reported. Conclusion: The combination therapy of EA and subsequent RFA is safe and effective as an alternative therapeutic method to treat PHPT in patients ineligible for parathyroidectomy.

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).

Ultrasound-Guided Radiofrequency Ablation for Primary Hyperparathyroidism Induced by Multiple Endocrine Neoplasia 1—A Case Report

Multiple endocrine neoplasia type 1 (MEN1) is a syndrome characterized by the occurrence of two or more endocrine gland tumors. Here, we show a case of a 52-year-old man diagnosed with MEN1 through gastrinoma, parathyroid adenoma and gene detection. The MEN1 patient’s case was complicated with relapsed primary hyperparathyroidism (PHPT), and they received ultrasound-guided radiofrequency ablation (RFA). The patient had a remarkable recovery after RFA treatment for the relapsed PHPT. It might be an alternative treatment for MEN1 patients with poor conditions such as high surgical risk, unwillingness to choose parathyroid surgery or those unable to tolerate surgery. Individualized therapy significantly benefits the prognosis of MEN1 patients.

Case report: coexistence of primary hyperparathyroidism with giant toxic nodular goiter

BACKGROUND

The coexistence of primary hyperparathyroidism (PHPT) and giant toxic nodular goiter is very rare. Moreover, PHPT could be easily overlooked because hyperthyroidism may also lead to hypercalcemia. A 99mTc-MIBI scan of the parathyroid glands is often negative when they are concomitant.

CASE PRESENTATION

Here, we report a rare case of the coexistence of giant toxic nodular goiter and PHPT that had been ignored for many years but was successfully treated with an ultrasound-guided parathyroid adenoma microwave ablation (MWA).

CONCLUSION

Reoperation for PHPT carries an increased risk of cure failure and complications. Thermal ablation has been proven effective in inactivating hyperfunctioning parathyroid lesions and in normalizing both serum parathyroid hormone (PTH) and calcium.

Efficacy and safety of radiofrequency ablation versus parathyroidectomy for secondary hyperparathyroidism in dialysis patients: a single-center retrospective study

We compared the efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) and parathyroidectomy (PTX) for the treatment of secondary hyperparathyroidism (SHPT). In this single-center retrospective study, we divided patients into PTX (n = 53) and RFA (n = 47) groups. The primary outcome was the proportion of patients who achieved the target intact parathyroid hormone (iPTH) concentration range (≤ 300 pg/mL). Secondary outcomes were the differences in the changes in iPTH, calcium, and phosphorus levels over time and prognosis. iPTH concentrations of 82.1% and 64.1% in the PTX and RFA groups, respectively, were within the recommended range at the endpoint (P = 0.07). iPTH concentrations in the PTX and RFA groups dropped sharply after treatment (82 ± 163 pg/mL and 280 ± 307 pg/mL, respectively, P < 0.001). There was no difference in the trends of iPTH, calcium, and phosphorus levels between the two groups (P > 0.05). Survival analysis revealed no differences in all-cause mortality and cumulative response rate between the two groups (P = 0.90, P = 0.14, respectively). Notably, the incidence of infection and length of the hospital stay in the RFA group were significantly lower. The preoperative bone-specific alkaline phosphatase concentration was a risk factor for postoperative hypocalcemia. US-guided RFA is minimally invasive and compared to PTX in terms of long-term efficacy and complications in the treatment of severe SHPT in maintenance dialysis patients. It may be used as an alternative technique to PTX; however, further studies are needed.

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.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

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.

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.

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.