Utility of intraoperative parathyroid hormone monitoring in patients with multiple endocrine neoplasia type 1-associated primary hyperparathyroidism undergoing initial parathyroidectomy

Less than subtotal parathyroidectomy in multiple endocrine neoplasia type 1: A case report and review of the literature

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Traditionally, the surgical approach for primary hyperparathyroidism in MEN1 is either subtotal or total parathyroidectomy.

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Advances in medical imaging allows more accurate preoperative localization of abnormal parathyroid gland.

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Recent studies showed less than subtotal parathyroidectomy has comparable outcome compared to subtotal or total parathyroidectomy.

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Further studies are needed to determine whether there are subsets of MEN1 patients that can benefit from less than subtotal parathyroidectomy.

Introduction

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome with common presenting signs and symptoms secondary to primary hyperparathyroidism (PHPT), which is managed surgically. Traditionally, either subtotal parathyroidectomy (SPTX) or total parathyroidectomy with autologous transplantation (TPTX) is the approach of choice. However, recent studies showed comparable persistence and recurrence rate in a subset of MEN1 patients (two or more concordant preoperative imaging results) who underwent less than subtotal parathyroidectomy (LSPTX).

Presentation of case

We report a case of patient with PHPT and delayed diagnosis of MEN1, who underwent LSPTX without intraoperative parathyroid hormone (IOPTH) measurement. The approach was chosen based on the preoperative imaging studies. Unfortunately, the PHPT persisted and the patient was reoperated. To further elucidate the issue, a systematic search of the literature was conducted on Cochrane library, PubMed, and Scopus; articles relevant to the case were reviewed. Results are conflicting results with most of the studies showed LSPTX is inferior compared to the other two approaches.

Discussion

Therefore, given the current body of evidence, we consider that subtotal or total parathyroidectomy is still the preferred surgical approach for the treatment of PHPT in MEN1.

Conclusion

Further studies are still needed to see whether LSPTX is comparable to SPTX or TPTX in regards to persistent and recurrent hyperparathyroidism if the conditions are met.

Optimal extent of initial parathyroid resection in patients with multiple endocrine neoplasia syndrome type 1: A meta-analysis

BACKGROUND

Hyperparathyroidism is an almost universal feature of multiple endocrine neoplasia type 1 syndrome. We present a systematic review and meta-analysis of the postoperative outcomes of patients undergoing initial operative treatment of primary hyperparathyroidism complicating multiple endocrine neoplasia 1.

METHODS

A comprehensive literature search was performed with a priori defined exclusion criteria for studies comparing total parathyroidectomy, subtotal parathyroidectomy, and less than subtotal parathyroidectomy.

RESULTS

Twenty-one studies incorporating 1,131 patients (272 undergoing total parathyroidectomy, 510 subtotal parathyroidectomy, and 349 less than subtotal parathyroidectomy) were identified. Pooled results revealed increased risk for long-term hypoparathyroidism in total parathyroidectomy patients (relative risk 1.61; 95% confidence interval, 1.12-2.31; P = .009) versus those undergoing subtotal parathyroidectomy. In the less than subtotal parathyroidectomy or subtotal parathyroidectomy comparison group, a greater risk for recurrence of hyperparathyroidism (relative risk 1.37; 95% confidence interval, 1.05-1.79; P = .02), persistence of hyperparathyroidism (relative risk 2.26; 95% confidence interval, 1.49-3.41; P = .0001), and reoperation for hyperparathyroidism (relative risk 2.48; 95% confidence interval, 1.65-3.73; P < .0001) was noted for less than subtotal parathyroidectomy patients, albeit with lesser risk for long-term for hypoparathyroidism (relative risk 0.47; 95% confidence interval, 0.29-0.75; P = .002).

CONCLUSION

Subtotal parathyroidectomy compares favorably to total parathyroidectomy, exhibiting similar recurrence and persistence rates with a decreased propensity for long-term postoperative hypoparathyroidism. The benefit of the decreased risk of hypoparathyroidism in less than subtotal parathyroidectomy is negated by the increase in the risk for recurrence, persistence, and reoperation. Future studies evaluating the performance of less than subtotal parathyroidectomy in specific multiple endocrine neoplasia 1 phenotypes should be pursued in an effort to delineate a patient-tailored, operative approach that optimizes long-term outcomes.

[Intraoperative measurement of parathyroid hormone in hyperparathyroidism]

Intraoperative parathyroid hormone (IOPTH) determination is based on the short half-life of parathyroid hormone (PTH) and the rapid analytical technology. The IOPTH provides functional information regarding correction of the overproductive state in hyperparathyroidism (HPT) and is superior to macroscopic evaluation of the parathyroid gland (PG) as well as any (intraoperative frozen section) form of histology (so-called biochemical frozen section). In this article the relevance and evaluation of IOPTH is defined for the most important forms of HPT, for primary HPT, renal secondary and tertiary HPT, multiple endocrine neoplasia type 1 (MEN1) and parathyroid carcinoma and clinical scenarios based on the currently available data. It becomes apparent that the additional benefits of IOPTH depend on diverse prerequisites of the specific type of HPT, the diagnostics as well as individual patient factors and strategic considerations for resection. Overall, the costs for IOPTH are comparably low and seem to be justified with respect to the gain in quality. In the hands of specialized endocrine surgeons IOPTH is an essential tool for intraoperative decision-making and quality assurance.

Could the Less-Than Subtotal Parathyroidectomy Be an Option for Treating Young Patients With Multiple Endocrine Neoplasia Type 1-Related Hyperparathyroidism?

Background: The surgical treatment of primary hyperparathyroidism (HPT) in patients with multiple endocrine neoplasia type 1 (MEN1) has evolved due the concern of permanent hypoparathyroidism. As the diagnosis has increased, the extent of operation has decreased. Most MEN1 patients requiring parathyroidectomy are younger than 50 years and they pose a difficult balance to achieve between persistent HPT and life-long hypoparathyroidism. The aim of the present study is to review our experience with a large series of patients with MEN1-related HPT (HPT/MEN1) treated at a single institution in order to find clues to a better treatment decision in these younger cases. Method: Retrospective analysis of consecutive HPT/MEN1 cases treated at a single institution with different operations: total parathyroidectomy and immediate forearm autograft (TPTX-AG), subtotal (STPTX), unintentional less than subtotal (U-LSTPTX) and intentional less than subtotal parathyroidectomy (I-LSTPTX). Results: Considering 84 initial cases operated on since 2011 (TPTX-AG, 39; STPTX, 22, U-LSTPTX, 13, and I-LSTPTX, 10), the rates of hypoparathyroidism were 30.8% (U-LSTPTX), 28.2% (TPTX-AG), 13.6% (STPTX), and 0% (I-LSTPTX). Two-thirds of them (68%; 57/84) were young (<50 years) or asdolescents. MIBI scan was more sensitive to show parathyroid glands and bilateral disease. Considering the concordance of MIBI and ultrasound for the possibility of unilateral clearance, it would be suitable to 22.6% of the cases. Intra-operative parathormone showed a significant decay even after unilateral exploration, but longer follow up is necessary. Overall, there were seven (4%) adolescents in 161 cases treated from 1987 to 2018, three underwent TPTX-AG and four had U-LSTPTX. Five are euparathyroid, one had mild recurrence, and one required a reoperation after 8 years due to the residual gland. Conclusions: Young patients are the most frequent candidates to parathyroidectomy. Less extensive procedures may be planned only if carefully reviewed preoperative imaging studies suggest a localized disease. Patients and their relatives should be fully informed of the risks and benefits during consent process. Future research with larger cohorts and long-term results are necessary to clarify if less than I-LSPTX or unilateral clearance are really adequate in selected groups of patients with HPT/MEN1 presenting lower volume of disease detected by preoperative imaging studies.

Multiple Endocrine Neoplasia Type 1 (MEN1): An Update and the Significance of Early Genetic and Clinical Diagnosis

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumor syndrome inherited in an autosomal dominant manner and characterized by a predisposition to a multitude of endocrine neoplasms primarily of parathyroid, enteropancreatic, and anterior pituitary origin, as well as nonendocrine neoplasms. Other endocrine tumors in MEN1 include foregut carcinoid tumors, adrenocortical tumors, and rarely pheochromocytoma. Nonendocrine manifestations include meningiomas and ependymomas, lipomas, angiofibromas, collagenomas, and leiomyomas. MEN1 is caused by inactivating mutations of the tumor suppressor gene MEN1 which encodes the protein menin. This syndrome can affect all age groups, with 17% of patients developing MEN1-associated tumors before 21 years of age. Despite advances in the diagnosis and treatment of MEN1-associated tumors, patients with MEN1 continue to have decreased life expectancy primarily due to malignant neuroendocrine tumors. The most recent clinical practice guidelines for MEN1, published in 2012, highlight the need for early genetic and clinical diagnosis of MEN1 and recommend an intensive surveillance approach for both patients with this syndrome and asymptomatic carriers starting at the age of 5 years with the goal of timely detection and management of MEN1-associated neoplasms and ultimately decreased disease-specific morbidity and mortality. Unfortunately, there is no clear genotype-phenotype correlation and individual mutation-dependent surveillance is not possible currently.

Intraoperative Decision-Making and Technical Aspects of Parathyroidectomy in Young Patients With MEN1 Related Hyperparathyroidism

One in 5,000 to 1 in 50,000 births have multiple endocrine neoplasia type 1 (MEN1). MEN1 is a hereditary syndrome clinically defined by the presence of two of the following endocrine tumors in the same patient: parathyroid adenomas, entero-pancreatic endocrine tumors and pituitary tumors. Most commonly, patients with MEN1 manifest primarily with signs and symptoms linked to primary hyperparathyroidism. By age 50, it is estimated that 100% of patients with MEN1 will have been diagnosed with primary hyperparathyroidism. These patients will need to undergo resection of their hyperfunctioning glands, however there is no clear consensus on which procedure to perform and when to perform it in these patients. In this original study we describe and explain the rational of our peri-operative approach and management at MD Anderson Cancer Center of MEN1 patients with hyperparathyroidism. This protocol includes preoperative evaluation, intraoperative decision-making and detailed surgical technique adopted for these patients' care. Additionally we review follow-up and disease management in instances of recurrent primary hyperparathyroidism in patients with MEN1 syndrome.

Unilateral Clearance for Primary Hyperparathyroidism in Selected Patients with Multiple Endocrine Neoplasia Type 1

Background

Primary hyperparathyroidism is the most common manifestation of multiple endocrine neoplasia type 1 (MEN1). Guidelines advocate subtotal parathyroidectomy (STP) or total parathyroidectomy with autotransplantation due to high prevalence of multiglandular disease; however, both are associated with a significant risk of permanent hypoparathyroidism. More accurate imaging and use of intraoperative PTH levels may allow a less extensive initial parathyroidectomy (unilateral clearance, removing both parathyroids with cervical thymectomy) in selected MEN1 patients with primary hyperparathyroidism.

Methods

We performed a retrospective cohort study at a high-volume tertiary medical center including patients with MEN1 and primary hyperparathyroidism, who underwent STP or unilateral clearance as their initial surgery from 1995 to 2015. Unilateral clearance was offered to patients who had concordant sestamibi and ultrasound showing a single enlarged parathyroid gland. For both the groups, we compared rates of persistent/recurrent disease and permanent hypoparathyroidism.

Results

Eight patients had unilateral clearance and 16 had STP. Subtotal parathyroidectomy patients were younger (37 vs 52 years). One patient in each group had persistent disease. One (13 %) unilateral clearance and five (31 %) STP patients had recurrent hyperparathyroidism after a mean follow-up of 47 and 68 months (p = 0.62). No unilateral clearance patients and two of 16 SPT patients had permanent hypoparathyroidism (p = 0.54).

Conclusions

Some MEN1 patients with primary hyperparathyroidism who have concordant localizing studies may be selected for unilateral clearance as an alternative to STP. For appropriately selected MEN1 patients, unilateral clearance can achieve similar results as STP and has no risk of permanent hypoparathyroidism, and may facilitate possible future reoperations.

Management impact: effects on quality of life and prognosis in MEN1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant endocrine tumor syndrome, caused by inactivating mutations of the MEN1 tumor suppressor gene at 11q13 locus, which predisposes to develop tumors in target neuroendocrine tissues. As the positional cloning and identification of the causative gene in 1997, genetic diagnosis, by the sequencing-based research of gene mutations, has become an important tool in the early and differential diagnosis of the disease. Application of the genetic test, in MEN1 index cases and in first-degree relatives of mutated patients, has been constantly increasing during the last two decades, also thanks to the establishment of multidisciplinary referral centers and specific genetic counseling, and thanks to the wide availability of high throughput instruments for gene sequencing and gene mutation identification. The MEN1 genetic test helps the specific diagnosis of probands, and allows the early identification of asymptomatic carriers, strongly contributing, together with progressions in tumor diagnostic techniques and in pharmacological and surgical therapeutic approaches, to the reduction of morbidity and mortality associated with the syndrome. International clinical guidelines for MEN1 have been drafted by panels of specialists in the field, with the main goal to improve the management of the disease and grant patients a better quality of life. Here, we review main recommendations and suggestions derived by the last published general guidelines in 2012, and by most recent published studies about MEN1 syndrome diagnosis, clinical management, therapeutic approaches and patients' quality of life.

Limited Parathyroidectomy in Multiple Endocrine Neoplasia Type 1-Associated Primary Hyperparathyroidism: A Setup for Failure

BACKGROUND

Recently, some surgeons have suggested that minimally invasive parathyroidectomy guided by preoperative localizing studies of patients with multiple endocrine neoplasia type 1 (MEN1)-associated primary hyperparathyroidism (pHPT) provides an acceptable outcome while minimizing the risk of hypoparathyroidism. This study aimed to evaluate the outcome for MEN1 patients who underwent limited parathyroidectomy compared with subtotal parathyroidectomy.

METHODS

The authors performed a retrospective analysis of 99 patients with MEN1-associated pHPT who underwent at least one parathyroid operation at their institution. Preoperative imaging studies, intraoperative findings, and clinical outcomes for patients were compared.

RESULTS

A total of 99 patients underwent 146 operations. Persistent pHPT was significantly higher in patients whose initial operations involved removal of 1 or 2 glands (69 %) or 2.5 to 3 glands (20 %) compared with those who had 3.5 or more glands removed (6 %) (P < 0.01). Persistent pHPT occurred in 5 % of all operations that cumulatively removed 3.5 or more parathyroid glands compared with 40 % of operations that removed 3 or fewer glands (P < 0.01). The single largest parathyroid gland was correctly identified preoperatively in 69 % (22/32) of the patients. However, preoperative localizing studies missed enlarged contralateral parathyroid glands in 86 % (19/22) of these patients. Preoperative localizing studies missed the largest contralateral parathyroid gland in 16 % (5/32) of the patients.

CONCLUSIONS

Limited parathyroidectomy in MEN1 is associated with a high failure rate and should not be performed. Preoperative identification of a single enlarged parathyroid gland in MEN1 is not reliable enough to justify unilateral neck exploration because additional enlarged contralateral parathyroid glands are frequently missed.

Multiple Endocrine Neoplasia: Genetics and Clinical Management

Early diagnosis of multiple endocrine neoplasia (MEN) syndromes is critical for optimal clinical outcomes; before the MEN syndromes can be diagnosed, they must be suspected. Genetic testing for germline alterations in both the MEN type 1 (MEN1) gene and RET proto-oncogene is crucial to identifying those at risk in affected kindreds and directing timely surveillance and surgical therapy to those at greatest risk of potentially life-threatening neoplasia. Pancreatic, thymic, and bronchial neuroendocrine tumors are the leading cause of death in patients with MEN1 and should be aggressively considered by at least biannual computed tomography imaging.

A randomized, prospective trial of operative treatments for hyperparathyroidism in patients with multiple endocrine neoplasia type 1

BACKGROUND

Hyperparathyroidism (HPT) in multiple endocrine neoplasia (MEN) type 1 is associated with multiglandular parathyroid disease. Previous retrospective studies comparing subtotal parathyroidectomy (SP) and total parathyroidectomy with autotransplantation (TP/AT) have not established clearly better outcomes with either procedure.

METHODS

Patients were assigned randomly to either SP or TP/AT and data were collected prospectively. The rates of persistent HPT, recurrent HPT, and postoperative hypoparathyroidism were compared.

RESULTS

The study cohort included 32 patients randomized to receive either SP or TP/AT (mean follow-up, 7.5 ± 5.7 years). The overall rate of recurrent HPT was 19% (6/32). Recurrent HPT occurred in 4 of 17 patients (24%) treated with SP and 2 of 15 patients (13%) treated with TP/AT (P = .66). Permanent hypoparathyroidism occurred in 3 of 32 patients (9%) overall. The rate of permanent hypoparathyroidism was 12% in the SP group (2/17) and 7% in the TP/AT group (1/15). A second operation was performed in 4 of 17 patients initially treated with SP (24%), compared with 1 of 15 patients undergoing TP/AT (7%; P = .34).

CONCLUSION

This randomized trial of SP and TP/AT in patients with MEN 1 failed to show any difference in outcomes when comparing results of SP versus TP/AT. Both procedures are associated with acceptable results, but SP may have advantages in that is involves only 1 surgical incision and avoids an obligate period of transient postoperative hypoparathyroidism.