Feasibility of Autofluorescence Using Overlay Imaging for the Detection of Parathyroid Glands: Defining Standards

BACKGROUND

The aim of this study is to define standards for the use of near-infrared autofluorescence (NIRAF)-based overlay imaging via EleVision IR (Medtronic, Dublin, Ireland) and to evaluate its clinical applicability.

PATIENTS AND METHODS

This prospective study included 189 patients who had undergone open thyroid and/or parathyroid surgery and in whom EleVision IR was applied to visualize at least one parathyroid gland (PG) between January 2021 and May 2022 in a tertiary referral care center. Whether the PGs were first localized by the surgeon or by overlay imaging was noted. Handling of the device, application time and duration, distance, infrared intensity (IR%), and the angle of each measurement were analyzed. In thyroidectomies, the specimens were subsequently scanned for further PGs. NIRAF patterns and intensities were described.

RESULTS

Overall, 543 PGs were analyzed in 158 (83.6%) surgeries of thyroid glands (TGs) and in 49 (25.9%) surgeries for hyperparathyroidism. In 111 (58.7%) patients, identical numbers of PGs were detected by the surgeon and by overlay imaging. While a larger number of PGs was identified by the surgeon in 48 (25.4%) patients, overlay imaging served to detect more PGs in 30 (15.9%) cases. In four (2.1%) patients, PGs were visualized post-thyroidectomy due to their autofluorescence on the specimen. NIRAF-based overlay imaging was applied to depict the PGs early on after exposure by the surgeon. The ideal distance for the measurement ranged between 8 and 12 cm with an angle of 90° and a mean IR% of 34.5% (± 17.6).

CONCLUSIONS

Considering the standard operating procedures, NIRAF-based overlay imaging can be used as an adjunct tool for intraoperative localization.

Does Genotype-Specific Phenotype in Patients with Multiple Endocrine Neoplasia Type 2 Occur as Current Guidelines Predict?

The clinical manifestation of multiple endocrine neoplasia type 2 (MEN2) in terms of developing medullary thyroid cancer (MTC), pheochromocytoma (PCC), and/or primary hyperparathyroidism (PHPT) is related to the respective pathogenic variant of the RET proto-oncogene. The aim of this study is to retrospectively analyze the individual, genotype-dependent clinical manifestations of a large cohort of MEN2 patients. By comparing their clinical profile with currently existing evidence-based knowledge, an optimal therapy and prevention strategy in terms of prophylactic thyroidectomy and clinical follow-up could be ensured. This is a retrospective single-center study of 158 MEN2 patients who were diagnosed and/or surgically treated at a tertiary referral care center between 1990 and 2022. All participants were categorized according to their pathogenic variant of the RET proto-oncogene. Subsequently, the clinical manifestation of the disease and its time of occurrence was documented. Our analysis showed results in line with existing studies, except for a considerably lower-than-predicted occurrence of PCC in patients with V804M/L mutations. This study supports the current recommendation regarding the pathogenic variant-dependent management of this rare cancer-associated syndrome.

Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study

BACKGROUND

Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours.

METHODS

In this retrospective, international, cross-sectional study, centres were invited to participate in June 22, 2022; each centre joining the study was asked to provide data from medical records on all surgical thyroidectomies consecutively performed from Jan 1, 2019, to Dec 31, 2021. Patients with indeterminate thyroid nodules were divided into three groups according to when they underwent surgery: from Jan 1, 2019, to Feb 29, 2020 (global prepandemic phase), from March 1, 2020, to May 31, 2021 (pandemic escalation phase), and from June 1 to Dec 31, 2021 (pandemic decrease phase). The main outcomes were, for each phase, the number of surgeries for indeterminate thyroid nodules, and in patients with a postoperative diagnosis of thyroid cancers, the occurrence of tumours larger than 10 mm, extrathyroidal extension, lymph node metastases, vascular invasion, distant metastases, and tumours at high risk of structural disease recurrence. Univariate analysis was used to compare the probability of aggressive thyroid features between the first and third study phases. The study was registered on ClinicalTrials.gov, NCT05178186.

FINDINGS

Data from 157 centres (n=49 countries) on 87 467 patients who underwent surgery for benign and malignant thyroid disease were collected, of whom 22 974 patients (18 052 [78·6%] female patients and 4922 [21·4%] male patients) received surgery for indeterminate thyroid nodules. We observed a significant reduction in surgery for indeterminate thyroid nodules during the pandemic escalation phase (median monthly surgeries per centre, 1·4 [IQR 0·6-3·4]) compared with the prepandemic phase (2·0 [0·9-3·7]; p<0·0001) and pandemic decrease phase (2·3 [1·0-5·0]; p<0·0001). Compared with the prepandemic phase, in the pandemic decrease phase we observed an increased occurrence of thyroid tumours larger than 10 mm (2554 [69·0%] of 3704 vs 1515 [71·5%] of 2119; OR 1·1 [95% CI 1·0-1·3]; p=0·042), lymph node metastases (343 [9·3%] vs 264 [12·5%]; OR 1·4 [1·2-1·7]; p=0·0001), and tumours at high risk of structural disease recurrence (203 [5·7%] of 3584 vs 155 [7·7%] of 2006; OR 1·4 [1·1-1·7]; p=0·0039).

INTERPRETATION

Our study suggests that the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic period could have led to an increased occurrence of aggressive thyroid tumours. However, other compelling hypotheses, including increased selection of patients with aggressive malignancies during this period, should be considered. We suggest that surgery for indeterminate thyroid nodules should no longer be postponed even in future instances of pandemic escalation.

FUNDING

None.

Surgery for primary hyperparathyroidism in Germany, Switzerland, and Austria: an analysis of data from the EUROCRINE registry

PURPOSE

EUROCRINE is an endocrine surgical register documenting diagnostic processes, indication for surgical treatment, surgical procedures, and outcomes. The purpose was to analyse data for PHPT in German speaking countries regarding differences in clinical presentation, diagnostic workup, and treatment.

METHODS

All operations for PHPT performed from 07/2015 to 12/2019 were analysed.

RESULTS

Three thousand two hundred ninety-one patients in Germany (9 centres; 1762 patients), Switzerland (16 centres; 971 patients) and Austria (5 centres; 558 patients) were analysed. Hereditary disease was seen in 36 patients in Germany, 16 patients in Switzerland and 8 patients in Austria. In sporadic disease before primary operation, PET-CT showed the highest sensitivity in all countries. In re-operations, CT and PET-CT achieved the highest sensitivities. The highest sensitivity of IOPTH was seen in Austria (98.1%), followed by Germany (96.4%) and Switzerland (91.3%). Operation methods and mean operative time reached statistical significance (p<0.05). Complication rates are low. Overall, 656 (19.9%) patients were asymptomatic; the remainder showed bone manifestations, kidney stones, fatigue and/or neuropsychiatric symptoms.

CONCLUSION

Early postoperative normocalcaemia ranged between 96.8 and 97.1%. Complication rates are low. PET-CT had the highest sensitivity in all three countries in patients undergoing primary operation as well as in Switzerland and Austria in patients undergoing re-operation. PET-CT could be considered a first-line preoperative imaging modality in patients with inconclusive ultrasound examination. The EUROCRINE registry is a beneficial and comprehensive data source for outcome analysis of endocrine procedures on a supranational level.

Primary Hyperparathyroidism and Intraoperative Parathyroid Hormone Monitoring: Application of a Modified Interpretation in Patients With "Parathyroid Hormone Spikes"

INTRODUCTION

Intraoperative parathyroid hormone (PTH) spikes occur in up to 30% of patients during surgery for primary hyperparathyroidism. This can lead to a prolonged PTH decline and cause difficulties in using current interpretation criteria of intraoperative PTH monitoring. The aim of this study aim was to evaluate an alternative interpretation model in patients with PTH spikes during exploration.

METHODS

1035 consecutive patients underwent surgery for primary hyperparathyroidism in a single center. A subgroup of patients with intraoperative PTH spikes of >50 pg/mL were selected (n = 277; 27.0%). The prediction of cure applying the Miami and Vienna criteria was compared with a decay of ≥50% 10 min after excision of the enlarged parathyroid gland using the "visualization value" (VV; =PTH level immediately after visualization of the gland) as basal value. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated.

RESULTS

Using the VV, sensitivity was 99.2% (Vienna 71.0%; Miami 97.7%), specificity was 18.2 (Vienna 63.6%; Miami 36.4%), and accuracy was 92.8 (Vienna 70.4%; Miami 92.8%). Of 255 single-gland disease patients, 72 were identified correctly as cured by applying the VV (P < 0.001), yet 10 of 22 patients with multiple-gland disease were missed compared with the Vienna Criterion (P = 0.002). The comparison with the Miami Criterion showed that six more patients were correctly identified as cured (P = 0.219), whereas four patients with multiple-gland disease were missed (P = 0.125).

CONCLUSIONS

Using the VV as a baseline in patients with intraoperative PTH spikes may prove to be an alternative and therefore can be recommended. However, if the VV is higher than the preexcision value, it should not be applied.

The value of intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidism and varying baseline parathyroid hormone levels

BACKGROUND

When applying intraoperative parathyroid hormone monitoring (IOPTH) to patients with primary hyperparathyroidism (PHPT), there are established criteria predicting biochemical cure in patients with basal parathyroid hormone (PTH) levels in the medium range (100-400 pg/ml); however, there is a challenge concerning patients with low (less than 100 pg/ml) or high (more than 400 pg/ml) basal PTH levels. The aim of this study was to investigate the value of the 'Vienna criterion' applied during IOPTH in patients with PHPT and various basal PTH concentrations.

METHODS

Consecutive patients between 1999-2009 with a biochemical diagnosis of PHPT who underwent surgical parathyroidectomy were included. Based on preoperative PTH levels they were divided into three groups: group 1 (low) (<100 pg/ml), group 2 (medium) (100-400 pg/ml) and group 3 (high) (>400 pg/ml) basal PTH. PTH was measured at the start of the operation, when the gland was excised and then at 5, 10 and 15 min after. Calcium and PTH levels were measured at 7 days and 12 months postoperatively. Sensitivity, specificity, positive and negative predictive value, as well as accuracy of IOPTH were calculated for the different groups postoperatively.

RESULTS

675 patients with PHPT were analysed. Sensitivity and specificity were 83.7 per cent and 66.7 per cent in group 1 (n = 187), 90.7 per cent and 69.2 per cent in group 2 (n = 433), and 94.4 per cent and 100 per cent in group 3 (n = 55) to predict cure. Preoperative creatinine (p = 0.002) showed significant statistical difference between the groups but was not related to intraoperative PTH decline. At 12 months follow-up normocalcaemia was documented in 98.9 per cent in group 1, 99.0 per cent group 2, and 98.0 per cent of group 3 patients.

CONCLUSION

Normocalcaemia was predicted intraoperatively by applying the 'Vienna criterion' in 98 to 100 per cent and was confirmed after 12 months follow-up in up to 99.0 per cent of patients. Low specificity and a high false-negative rate in patients with low basal PTH show that other criteria might be better suited for this group.

Accessing the influence of 99mTc-Sesta-MIBI-positive thyroid nodules on preoperative localisation studies in patients with primary hyperparathyroidism

Purpose

Curative treatment for primary hyperparathyroidism (PHPT) is parathyroidectomy (PTX) with removal of the hyperfunctioning gland(s). In an endemic goitre region, 35–78% of PHPT patients show concomitant thyroid disease. This study aimed to evaluate if ^99mTc-sestamibi (MIBI)-positive thyroid nodules decrease sensitivity in regard to localising the hyperfunctioning parathyroid gland(s) in PHPT patients.

Methods

Within 5 years, 497 consecutive patients with biochemically proven PHPT were included in this study. The data was analysed retrospectively.

Results

In total, 198 patients underwent PTX with thyroid surgery and 299 patients underwent sole PTX. Sensitivity of MIBI scan for PTX with and without thyroid surgery was 72.1% and 73.6%, respectively. A statistically significant difference in sensitivity of ultrasound for PTX with and without thyroid surgery (57.0% and 70.9%, respectively) was observed (p = 0.029). Thyroid nodule histology did not have a significant effect on the MIBI scan. Unilateral neck exploration (UNE) was performed in 110 patients and bilateral neck exploration (BNE) in 177 patients. The probability of surgical conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

Conclusions

Concomitant benign thyroid nodules did not influence MIBI sensitivity. No correlation between thyroid carcinoma and MIBI uptake was determined. However, MIBI detection of thyroid malignancy is important in patients initially being considered for minimal invasive parathyroidectomy. Sensitivity and positive predictive value of ultrasound were significantly lower in patients with thyroid nodules. The probability of conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

Positive central lymph-nodes are underdiagnosed in patients with Bethesda V cytology in an endemic goiter region

Background

Fine needle aspiration (FNA) is a significant diagnostic procedure for detecting malignancy in patients with nodular thyroid disease. A high proportion of patients with cytological diagnosed follicular neoplasia (Bethesda IV and V) ultimately have thyroid cancer. The aim of this study was to evaluate the incidence of preoperatively undiagnosed central lymph node metastasis in patients with multinodular goiter (MNG).

Methods

Patients who underwent FNA and were classified as Bethesda IV/V were included. Applying a radical approach, all patients underwent (hemi)thyroidectomy and prophylactic unilateral central neck dissection.

Results

During our study period 2009-2013, 60 patients (19.7%) were classified as Bethesda IV and 21 (6.9%) Bethesda V. Final histopathological results revealed malignancy in 35 (43.2%) of 81 Bethesda IV/V nodules. Of the nodules classified as Bethesda IV, 20 (33.3%) showed malignancy in the final histology. Ten patients (16.7%) had papillary micro-carcinoma (mPTC, <10 mm), 4 (6.6%) PTC and 6 (10%) follicular thyroid cancer. Fifteen of 21 (71.4%) Bethesda V nodules were revealed as PTC of whom seven (33.3%) patients also had lymph-node metastases.

Conclusions

While 33.3% of the patients with PTC, preoperatively classified as Bethesda V, had previously undetected positive lymph-nodes, only one patient with Bethesda IV had lymph-node metastasis.