Thyroid Cancer Detection with Dual-isotope Parathyroid Scintigraphy in Primary Hyperparathyroidism

Surgical Approach to Primary Hyperparathyroidism in Patients with Concomitant Thyroid Diseases: A Retrospective Single Center Study

BACKGROUND

Primary hyperparathyroidism (PHPT) and thyroid diseases are a frequent concomitant occurrence, but the surgical approach to associated disease is still debated.

METHODS

We retrospectively evaluated a series of PHPT patients focusing on thyroid disease and surgery.

RESULTS

Among 238 PHPT patients undergoing parathyroidectomy (PTX) between 2002 and 2017, 128 were affected also by a benign thyroid disease, namely, goiter in 118 (76 multinodular (MNG) and 42 uninodular (UNG)), autoimmune thyroiditis in 10, and hyperthyroidism in 21. Surgical approach was unilateral neck exploration (UNE) in 59 patients and bilateral neck exploration (BNE) in 69. The PHPT cure rate was 94%. On comparing patients submitted to PTX only and PTX plus thyroidectomy (TX), in the latter MNG and hyperthyroidism were more frequent, and surgical time and length of stay were longer. No difference in surgical complications was found between patients undergoing UNE and BNE.

CONCLUSION

PHPT patients with a concomitant thyroid disease underwent double surgery in almost two-thirds of the cases, mostly by BNE. The main factors driving the decision to perform concomitant PTX and TX were the presence of thyroid nodular disease with the nodule site ipsilateral to the presurgically localized parathyroid adenoma.

Diagnostic Performance of Technetium-99m Methoxy-Isobutyl-Isonitrile for Differentiation of Malignant Thyroid Nodules: A Systematic Review and Meta-Analysis

BACKGROUND

The purpose of the current study was to investigate the diagnostic performance of technetium-99m (Tc-99m) methoxy-isobutyl-isonitrile (MIBI) for differentiation of malignant thyroid nodules (TN) through a systematic review and meta-analysis.

METHODS

The MEDLINE/PubMed and EMBASE database, from the earliest available date of indexing through January 31, 2018, were searched for studies evaluating the diagnostic performance of Tc-99m MIBI for TN. The sensitivities and specificities were determined across studies, positive and negative likelihood ratios (LR+ and LR-) were calculated, and summary receiver operating characteristic curves were constructed.

RESULTS

Across 22 studies (2421 patients), the pooled sensitivity for Tc-99m MIBI thyroid scan was 0.87 [confidence interval (CI) 0.76-0.93] with heterogeneity (I² = 92.3) and a pooled specificity of 0.78 [CI 0.67-0.86] with heterogeneity (I² = 96.4). LR syntheses gave an overall LR+ of 4.0 [CI 2.5-6.3] and LR- of 0.17 [CI 0.09-0.32]. The pooled diagnostic odds ratio was 24 [CI 63-176]. The hierarchical summary receiver operating characteristic curve indicates that the area under the curve was 0.90 [CI 0.87-0.92]. In meta-regression analysis, no definite variable was the source of the study heterogeneity.

CONCLUSION

The current meta-analysis shows a moderate sensitivity and specificity of Tc-99m MIBI thyroid scan for differentiation of malignant TN. However, the diagnostic odds ratio was relatively low and the LR scattergram indicated that Tc-99m MIBI thyroid scan is not useful for confirming the presence of malignant TN or for its exclusion. Therefore, Tc-99m MIBI thyroid scans should be used restrictively and interpreted cautiously when assessing TN for malignancy.

Recent Development of Nuclear Molecular Imaging in Thyroid Cancer

Therapies targeting specific tumor pathways are easy to enter the clinic. To monitor molecular changes, cellular processes, and tumor microenvironment, molecular imaging is becoming the key technology for personalized medicine because of its high efficacy and low side effects. Thyroid cancer is the most common endocrine malignancy, and its theranostic radioiodine has been widely used to diagnose or treat differentiated thyroid cancer. This article summarizes recent development of molecular imaging in thyroid cancer, which may accelerate the development of personalized thyroid cancer therapy.

99mTc-Sestamibi/123I Subtraction SPECT/CT in Parathyroid Scintigraphy: Is Additional Pinhole Imaging Useful?

Objectives

This retrospective study evaluated whether the use of additional anterior ^99mTc-sestamibi/¹²³I pinhole imaging improves the outcome of ^99mTc-sestamibi/¹²³I subtraction SPECT/CT in parathyroid scintigraphy (PS).

Materials and Methods

PS using simultaneous dual-isotope subtraction methods and an acquisition protocol combining SPECT/CT and planar pinhole imaging was performed for 175 patients with primary or secondary hyperparathyroidism. All patients who proceeded to surgery with complete postsurgery laboratory findings were included in this study (n = 94). SPECT/CT images alone and combined with pinhole images were evaluated.

Results

There were 111 enlarged parathyroid glands of which 104 and 108 glands were correctly visualized by SPECT/CT (seven false positives) or SPECT/CT with pinhole (three false positives), respectively. Both sensitivity and specificity were higher with combined SPECT/CT with pinhole than with SPECT/CT alone (97% versus 94% and 99% versus 98%, resp., not significant). The false-positive rate was 6% with SPECT/CT and decreased to 3% using combined SPECT/CT with pinhole.

Conclusion

^99mTc-sestamibi/¹²³I subtraction SPECT/CT is a highly sensitive and specific protocol for PS. The use of additional anterior pinhole imaging increases both sensitivity and specificity of PS, although this increase is not statistically significant.

Concomitant thyroid disease and primary hyperparathyroidism in patients undergoing parathyroidectomy or thyroidectomy

BACKGROUND

Thyroid abnormalities have been found intraoperatively during parathyroidectomy and have resulted in concomitant thyroidectomy. The identification of concomitant disease is important prior to primary operation in order to minimize reoperations. This study investigates the incidence of concomitant primary hyperparathyroidism (PHPT) and thyroid nodular disease in patients undergoing thyroidectomy or parathyroidectomy.

METHODS

We performed a retrospective review of prospectively gathered data for 621 patients who underwent thyroidectomy, parathyroidectomy, or both at Tulane Medical Center. Information obtained included initial referral, initial thyroid stimulating hormone (TSH), initial parathyroid hormone (PTH), fine needle aspiration (FNA) results, ultrasound results, type of operation performed, final diagnosis, and final pathology.

RESULTS

Among the 400 patients referred primarily for thyroid disease, 13.50% underwent a thyroidectomy and parathyroidectomy (PTX) simultaneously and 10.75% received a final diagnosis of thyroid and concomitant parathyroid disease. Among the 103 patients referred primarily for parathyroid disease, 26.21% underwent a PTX and thyroidectomy and 24.27% received a final diagnosis of both thyroid and parathyroid disease. Patients referred primarily for parathyroid disease were more likely to receive a final diagnosis of both parathyroid and thyroid disease and were more likely to undergo a combined operation.

CONCLUSIONS

Concomitant thyroid and parathyroid disease occur and preoperative analysis is important to avoid increased complications from reoperations.

Scan-directed mini-incision focused parathyroidectomy: how accurate is accurate enough?

INTRODUCTION Mini-incision focused parathyroidectomy (MI-FP) is advocated as an alternative to bilateral neck exploration (BNE), owing to its reduced morbidity. The site and side of the affected gland is identified preoperatively using a combination of ultrasound and sestamibi scans. However, the acceptable degree of inter-scan concordance required to prompt MI-FP without compromising accuracy is undetermined. METHODS Accuracy of preoperative imaging was determined both individually and in combination for all parathyroidectomies (2007-2014). A grading system (excellent, good, poor) was devised to describe the interscan concordance, which was validated by the operative and histological findings. RESULTS Eighty-nine patients (17 male, 68 female) underwent parathyroidectomy (MI-FP 44, BNE 45). The accuracy of scans interpreted individually was 53% for ultrasound and 60% for sestamibi, with no difference according to surgical technique (P = 0.43, P = 1, respectively). The proportion of interscan concordance was: excellent - 35%, good - 40%, poor 25%. Combined accuracy was 100% for both excellent and good grades but only 13% for those graded poor. Similar rates of normocalcaemia were observed for MI-FP and BNE, while postoperative hypocalcaemia was five times higher in those undergoing BNE. CONCLUSIONS Reduction in the inter-scan concordance from excellent to good does not compromise accuracy. MI-FP could be successfully performed in up to 75% of patients - 25% higher than recommended in national guidelines. Focused parathyroidectomy does not compromise surgical and endocrinological outcomes but boasts a far superior complication rate.

Serum Calcium and Risk of Nonmedullary Thyroid Cancer in Patients with Primary Hyperparathyroidism

Background

Clinical cases of nonmedullary thyroid carcinoma (NMTC) in combination with primary hyperparathyroidism (PHPT) have been reported occasionally. However, the clinical characteristics and risk factors of concomitant NMTC in PHPT patients remain unclear. This study aimed to assess the association between PHPT and NMTC, and evaluate the clinical characteristics and risk factors of NMTC in Chinese patients with PHPT.

Material/Methods

This was a retrospective cohort analysis. We reviewed the medical records of 155 patients who underwent surgery for PHPT in two large medical centers in China between 2009 and 2014. The clinical manifestations, biochemical abnormalities, and histological characteristics of PHPT patients were analyzed.

Results

Of the 155 patients with PHPT, 58 patients (37.4%) had thyroid nodules and 12 patients (7.7%) were ill with concomitant NMTC. PHPT patients with NMTC demonstrated significantly lower preoperative serum calcium levels compared to PHPT patients with benign thyroid nodules (p<0.05). A significantly negative association between preoperative serum calcium levels and the presence of NMTC was found in PHPT patients (p<0.05). Furthermore, ROC analysis revealed that albumin-corrected serum calcium levels <2.67 mmol/L had good capacity to differentiate the PHPT patients with NMTC from those with benign thyroid nodules.

Conclusions

Compared with the reported much lower prevalence of thyroid carcinoma in the general population, our results suggest that PHPT might be a risk factor for the malignancy of thyroid nodules; a lower level of serum calcium may predict the existence of NMTC in PHPT patients with thyroid nodules.

Incidental Finding of Papillary Thyroid Carcinoma in the Patients with Primary Hyperparathyroidism

OBJECTIVE

The relationship between primary hyperparathyroidism (pHPT) and papillary thyroid cancer (PTC) still remains unclear. We aimed to investigate the incidence of the co-existence of pHPT and PTC.

MATERIALS AND METHODS

Between 2010 and 2013, all patients with pHPT were retrospectively reviewed and those undergoing concomitant thyroid surgery were recorded. Of these, patients with a pathological result showing papillary or micro-papillary thyroid cancer were included into the study. A chart review of 228 patients who underwent surgery for pHPT revealed 86 (37.7%) patients with concurrent thyroid disease requiring surgical treatment.

RESULTS

Thyroid cancer was noted in six female patients (6.9%) undergoing thyroid resection, and 2.6% of all patients with pHPT. Four patients underwent total thyroidectomy while lobectomy was applied in the remaining two. None of the cases with lobectomy required a completion thyroidectomy.

CONCLUSION

We demonstrated the concurrence of PTC and pHPT at a rate of 2.6% which appeared as a coincidental pathology; however, thyroid disorders, seen in one of three patients with pHPT, were not uncommon. Further research is still needed to develop a reliable explanation for relationship between pHPT and non-medullary thyroid cancer.

Parathyroid dual tracer subtraction scintigraphy: small regions method for quantitative assessment of parathyroid adenoma uptake

OBJECTIVE

The aim was quantitative assessment of parathyroid adenoma (PTA) uptake in dual tracer dynamic scintigraphy.

METHODS

In 78 patients, median age 58 (19-80) years, surgically treated for primary hyperparathyroidism (PHPT), with parathyroid hormone median 125 (70-658) pg/ml, we performed preoperative parathyroid scintigraphy, following EANM guidelines of subtraction and double-phase protocol (2009) using two tracers: Tc-99m pertechnetate and Tc-99m MIBI. In addition to standard subtraction processing and visual interpretation of delayed MIBI planar images of neck and mediastinum in oblique sections (positions according to ultrasound PTA localisation), we developed Submarine processing software that enables selecting custom regions grid sizes ≥6 mm (as this solution was not present in commercial software) to follow time activity curve changes in thyroid tissue and PTA. Histopathology in 53/78 patients revealed PHPT and in 25/78 patients thyroid nodular disease only, and thyroid malignancy occurred in total of 15/78 (19 %) patients. PHPT group included 44 solitary PTA, 8 patients with hyperplasia and one parathyroid carcinoma. The median macroscopic volume of PTA was 717.5 (15-6125) mm(3). Concomitant PHPT and thyroid nodular disease occurred in 24/53 patients and among them 8 patients had thyroid malignancies.

RESULTS

PTA showed typical pattern of late peak on time activity curves characterized by median start time on 15 (10-25) min, the peak amplitude mean 19 (±5) % above thyroid declining washout curve, and duration of peak 6 (4-10) min, allowing PTA to "emerge" like submarine, independent from thyroid tissue and lesions. The ratio of PTA-to-normal thyroid uptake at peak maximum was 1.35 (±0.21). The thyroid TACs results of normal 29/78 (37 %) patients, benign nodular 34/78 (44 %) patients, and malignancy in 15 (19 %) patients were all presented by declining exponential curves. The slope analysis of TACs in normal thyroid tissue, thyroid benign and malignant lesions (linear fitted logarithm of TAC) showed no difference (the same negative slope: -0.04). Submarine processing was sensitive in detection of small lesions, in hyperplasia, and concomitant thyroid nodular disease.

CONCLUSIONS

The novel Submarine processing confirmed specific PHPT pattern and was effective in the group with potential pitfalls of standard interpretation, increasing sensitivity and specificity of standard processing subtraction algorithm. Prolonged MIBI accumulation was present in malignant as well as benign thyroid nodules with identical TAC slope.

Association of synchronous medullary and papillary thyroid carcinomas with primary hyperparathyroidism: first case report and literature review

OBJECTIVE

We report a case of a patient with symptomatic primary hyperparathyroidism who was found, through a thorough radiological investigation, to also have papillary and medullary thyroid carcinomas.

CASE REPORT

A 59-year-old female was diagnosed with primary hyperparathyroidism. A further radiological investigation found suspicious areas within both thyroid lobes that were later diagnosed as foci of papillary and medullary thyroid carcinomas. Appropriate treatment was commenced. Reports of similar occurrences of synchronous thyroid and parathyroid pathologies are discussed.

CONCLUSION

To our knowledge, this is the first reported case of two synchronous thyroid cancers occurring in the context of primary hyperparathyroidism. We strongly recommend a thorough radiological investigation of all patients with primary hyperparathyroidism to prevent missing concurrent thyroid cancers.

Sestamibi scintigraphy for parathyroid localisation: a reminder of the dangers of false positives

Surgical parathyroidectomy is the only curative treatment for primary hyperparathyroidism. As minimally invasive parathyroidectomy increases in popularity, so does reliance on preoperative parathyroid localisation techniques. One such technique is sestamibi scintigraphy. We report a case of false-positive sestamibi scintigraphy caused by follicular variant of papillary thyroid carcinoma. Subsequent completion thyroidectomy was not possible due to widespread postoperative fibrosis. This case, therefore, highlights the potential dangers of false-positive results due to thyroid carcinoma and encourages surgeons to consider this possibility when faced with intrathyroidal or otherwise ambiguous parathyroid localisation results.

Surgeon-driven thyroid interrogation of patients presenting with primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (pHPT) is an increasingly prevalent disease affecting all age groups. The authors sought to determine the impact of a "thyroid interrogation" practice protocol on the surgical treatment of patients with the diagnosis of pHPT referred to a single surgeon.

STUDY DESIGN

We performed a retrospective review of prospectively gathered data on parathyroidectomy (PTX) patients undergoing both a prospective clinical thyroid evaluation and thyroid ultrasound between January 2008 and October 2012.

RESULTS

Only 5.6% of 468 PTX patients were referred to a single surgeon for both parathyroid and thyroid surgical evaluation; 31% of patients had known pre-existing thyroid disease (hypothyroidism most commonly), and 22% of patients had palpable thyroid abnormalities unrecognized in 67% of cases by the referring physician. Of the 468 patients, 2.6% had a history of classic head and neck radiation exposure, 2.6% a history of radio-iodine treatment, and 3% a family history of thyroid cancer. Thyroid abnormalities were found on ultrasound in 61% of patients, and 26% of patients underwent thyroid biopsies. Parathyroid and thyroid surgery was combined for 18.4% of patients; indications included obstructive symptoms (3.2%), hyperthyroidism (0.9%), intraoperative findings (5.1%), and concern for malignancy (9.2%). Malignancy was diagnosed in 23 patients (4.9%), only 8 of whom had been referred for thyroid evaluation.

CONCLUSIONS

The majority of patients referred for PTX had evidence of thyroid pathology. For an important minority of these patients, benign and malignant disease was identified that merited surgical treatment at the time of PTX. We recommend comprehensive thyroid evaluation of patients referred for PTX.

Do giant parathyroid adenomas represent a distinct clinical entity?

BACKGROUND

The size of abnormal parathyroid glands in patients with primary hyperparathyroidism (PHPT) is highly variable, but the clinical significance of giant glands is unknown.

METHODS

We reviewed 300 consecutive patients after parathyroidectomy for PHPT. We compared patients with giant parathyroid adenomas (weight ≥95th percentile) with the remaining patients.

RESULTS

Giant adenomas were defined as weight ≥95th percentile or 3.5 g (median, 0.61; range, 0.05-29.93). Patients with giant adenomas had a greater mean preoperative calcium level, greater mean parathyroid hormone (PTH) level, and were less likely to have multiglandular or symptomatic disease. Giant adenomas were successfully localized on imaging in 87% of patients, which was not increased over other patients (82%). There were no differences between the groups in age, gender, gland location, or the incidence of persistent or recurrent hyperparathyroidism. Finally, giant glands had an increased incidence of symptomatic postoperative hypocalcemia, including 1 patient who required rehospitalization after removal of a giant gland.

CONCLUSION

Giant parathyroid adenomas have a distinct presentation characterized by single gland disease and lower incidence of symptoms despite increased levels of calcium and PTH. Additionally, after resection of a giant adenoma, patients are more likely to develop symptomatic hypocalcemia.

Diagnostic performance of (99m)Tc-MIBI scan in predicting the malignancy of thyroid nodules: a meta-analysis

Several studies have investigated the diagnostic performance of (99m)Tc-MIBI scan in the evaluation of thyroid nodules suspicious for malignancy with conflicting results. The aim of our study is to meta-analyze published data on this topic. A comprehensive literature search of studies published through December 2012 regarding the diagnostic performance of (99m)Tc-MIBI scan in the evaluation of thyroid nodules suspicious for malignancy was carried out. Pooled sensitivity and specificity of (99m)Tc-MIBI scan on a per lesion-based analysis and the area under the ROC curve were calculated. Pathological reports of thyroid nodules were considered as reference standard. Twenty-one studies were included in the meta-analysis. Pooled sensitivity and specificity of (99m)Tc-MIBI scan in detecting malignant thyroid nodules were 85.1 % [95 % confidence interval (95 % CI): 81.1-88.5 %] and 45.7 % (95 % CI: 42.7-48.7 %), respectively, on a per lesion-based analysis, irrespective of eventual results of previous technetium pertechnetate ((99m)TcO4) or iodine-123 ((123)I) scan. The area under the ROC curve was 0.78. A sub-analysis restricted to data on hypofunctioning nodules on (99m)TcO4 or (123)I scans was performed: pooled sensitivity and specificity of (99m)Tc-MIBI scan in these nodules were 82.1 % (95 % CI: 77.2-86.3 %) and 62.8 % (95 % CI: 58.9-66.7 %), respectively, on a per lesion-based analysis. The area under the ROC curve was 0.81. (99m)Tc-MIBI scan is a sensitive diagnostic tool in predicting the malignancy of thyroid nodules. Therefore, this imaging method could be helpful in patients with thyroid nodules in which malignancy is suspected on the basis of conventional diagnostic techniques. Higher specificity can be reached when hypofunctioning thyroid nodules are considered.