Local resection versus radical surgery for parathyroid carcinoma: A National Cancer Database analysis

[Endocrine oncology : An update on surgical treatments]

BACKGROUND

In the management of solid tumours, routine concepts are increasingly being transformed into individualized patient treatment. Endocrine surgery is traditionally characterized by resection strategies that are adapted to phenotype and genotype of the underlying disease. As complication rates in surgery correlate with the extent of resection, continuous efforts are made to identify selection criteria in order to limit the extent of surgery without compromising the oncological outcome. The aim is to design risk-stratified precision endocrine surgery.

MATERIALS AND METHODS

A search was carried out in PubMed for new and modern strategies and approaches for oncological endocrine surgery.

RESULTS

Several developments in surgical technique and technology, molecular pathology, medical therapy, and study data identify the potential to adapt the surgical strategy in all areas of endocrine surgery.

CONCLUSION

According to prevalent data, limited extent of resection in thyroid cancer surgery shows a reduction in complication rates while preserving oncological outcome when adequate selection criteria are implemented. New insights and innovative technologies also influence additional areas in oncological endocrine surgery for parathyroid, adrenal, and neuroendocrine neoplasia. However, the broad practice of these new concepts needs to be evaluated with regard to long-term oncological outcome.

Approach to the Patient With Parathyroid Carcinoma

Parathyroid carcinoma (PC) is usually associated with severe symptomatic primary hyperparathyroidism (PHPT) and accounts for less than 1% of all cases of PHPT and approximately 0.005% of all cancers. PC most commonly occurs as a sporadic disease and somatic CDC73 mutations can be detected in up to 80% of cases. Approximately 30% of patients harbor a germline mutation of the CDC73 gene. Preoperative diagnosis of PC is difficult because no disease-specific markers are available, and PC should be suspected in patients with severe hypercalcemia and end-organ complications. The diagnosis is based on the evidence of invasive tumor growth at histology and/or metastases. En bloc resection of the tumor, together with the ipsilateral thyroid lobe and adjacent structures, should be performed by an experienced surgeon when PC is suspected. This surgical approach reduces the risk of recurrence and metastasis and offers the highest chance of cure. Nonetheless, PC has a recurrence rate of 40% to 60% and, if feasible, multiple surgical procedures should be performed. When surgery is no longer an option, medical treatment is aimed to reduce hypercalcemia and target organ complications. Targeted agents have been effectively used in a few cases. We describe herein a patient with severe PHPT due to PC and provide a systematic diagnostic and treatment approach. A thorough review of the medical history, a typical clinical and biochemical phenotype and, in some cases, the revision of the histological examination provide the clues for the diagnosis of PC.

Parathyroid carcinoma: molecular therapeutic targets

Parathyroid carcinoma (PC) is an extremely rare malignant tumor of the parathyroid glands, accounting for less than 1% of primary hyperparathyroidism, commonly characterized by severe and unmanageable hypercalcemia, aggressive behavior, high metastatic potential, and poor prognosis. PC manifests prevalently as a sporadic tumor and only occasionally it is part of congenital syndromic and non-syndromic endocrine diseases. Molecular pathogenesis of this form of parathyroid tumor is not fully elucidated and it appears to be caused by multiple genetic and epigenetic drivers, differing among affected patients and not yet clearly stated in distinguishing PC from the benign parathyroid adenoma (PA). Congenital forms of PC have been prevalently associated with germline heterozygous loss-of-function mutations of the CDC73 tumor suppressor gene, both in the context of the hyperparathyroidism jaw-tumor syndrome (HPT-JT) and of the isolated familial hyperparathyroidism (FIPH). Currently, surgical en bloc resection of affected gland(s) and other involved structures is the elective therapy for both primary and recurrent PC. However, it usually results ineffective for advance and metastatic disease, and a high percentage of post-operative recurrence is reported. Targeted medical therapies for surgically untreatable PC, based on the molecular profile of PC samples, are, therefore, needed. The characterization of genetic and epigenetic alterations and deregulated pathways in PC samples will be of fundamental importance to tailor treatment for each patient. Here, we reviewed main findings on molecular pathogenetic aspects of PC, and the current state of the art of therapies.

Parathyroid carcinoma: Current management and outcomes – A systematic review

OBJECTIVE

Parathyroid carcinoma is rarely encountered in clinical practice. When faced with this clinical challenge, there is currently a paucity of evidence available for the optimal management of patients with parathyroid carcinoma. This systematic review synthesizes the available literature to evaluate the optimal management approach, thus providing guidance for future management.

METHODS

A systematic review was conducted according to PRISMA guidelines using Ovid MEDLINE, EMBASE, and PubMed databases for studies, published in English, reporting on parathyroid carcinoma. Full text of potentially eligible articles were reviewed by two authors independently and eligible studies selected. Treatment options and associated outcomes were evaluated. Descriptive statistics were used to describe pooled patient cohorts.

RESULTS

3203 articles were initially identified using the search criteria with 59 full-text articles then screened for eligibility. Seven articles, all retrospective studies, concerning 2307 patients (median 224/study). Parathyroidectomy alone was the most frequently utilised surgical approach across all studies, followed by en-bloc resection (with adjacent thyroid and/or nodal tissue). There was no difference in post-operative morbidity, mortality or survival between surgical approaches (p < 0.005). Patients who underwent either form of surgery had longer overall survival than those managed non-operatively (p < 0.005).

CONCLUSION

Surgical resection is the optimal treatment of parathyroid carcinoma. However there remains no consensus on the optimal extent of surgery, and as such future randomised prospective studies are necessary to evaluate the effects of different surgical approaches on morbidity, mortality and oncologic outcomes. Following resection, long-term surveillance with PTH is advised.

Parathyroid carcinoma: lessons from a rare malignancy of head and neck-a case series

Parathyroid carcinoma (PC) is a very rare head-neck malignancy. Because the symptoms of parathyroid carcinoma are similar to those of benign causes of hyperparathyroidism, it may be not easy to detect it before surgery. The management of PC after initial surgery will be perplexing because of the adequacy of surgery. We wish to describe the difficulties encountered throughout treatment using a literature review. We conducted a retrospective analysis of individuals with parathyroid carcinoma who had treatment at our department between 2017 and 2022. We gathered data on the clinical profile, investigations, management of hypercalcemia, surgical techniques, histopathological features, adjuvant therapy, and outcomes. We treated three patients with parathyroid carcinoma: Two patients with inferior parathyroid carcinoma and one with superior parathyroid carcinoma. Generalized weakness and bony pain are the predominant symptoms. In all cases, the tumor was located using 99Tc MIBI / SPECT scintigraphy and Ultrasonography. Hemithyroidectomy and tumor excision were done as the surgery of choice. All are disease-free at the 12th-month follow-up. We suggested that parathyroid hormone testing be performed in all bony fibrous lesions to rule out hyperparathyroidism. PC is a likely diagnosis when there is noticeable throat swelling, elevated PTH levels greater than 400 IU/L, and serum calcium levels greater than 15 mg/dL.

A Nomogram for Relapse/Death and Contemplating Adjuvant Therapy for Parathyroid Carcinoma

Parathyroid carcinoma (PC) is a rare endocrine malignancy with an increased incidence in the last decade. There is no reliable prognostic staging system for PC. Several hosts, tumors, and tumor microenvironment factors have been negatively correlated with survival in the last decade. Surgical resection with negative margins is still the standard of treatment in PC. Chemo and radiotherapy have no proven beneficial effect. A new promising approach with molecular profiling could lead to adjuvant therapies.

Margin Free Resection Achieves Excellent Long Term Outcomes in Parathyroid Cancer

Long-term outcomes of parathyroid cancer remain poorly documented and unsatisfactory. This cohort includes 25 consecutive parathyroid cancer patients with median follow-up of 10.7 years (range 4.1−26.5 years). Pre-operative work-up in the center identified a suspicion of parathyroid cancer in 17 patients. En bloc resection, including the recurrent laryngeal nerve in 4/17 (23.5%), achieved cancer-free resection margins (R0) in 82.4% and lasting loco-regional disease control in 94.1%. Including patients referred after initial surgery elsewhere, R0 resection was achieved in merely 17/25 (68.0%) of patients. Cancer-positive margins (R1) in 8 patients led to local recurrence in 50%. On multivariate analysis, only margin status prevailed as independent predictor of recurrence free survival (χ2 19.5, p < 0.001). Local excision alone carried a 3.5-fold higher risk of positive margins than en bloc resection (CI95: 1.1−11.3; p = 0.03), and a 6.4-fold higher risk of locoregional recurrence (CI95: 0.8−52.1; p = 0.08). R1-status was associated with an 18.0-fold higher risk of recurrence and redo surgery (CI95: 1.1−299.0; p = 0.04), and a 22.0-fold higher probability of radiation (CI95: 1.4−355.5; p = 0.03). In patients at risk, adjuvant radiation reduced the actuarial risk of locoregional recurrence (p = 0.05). When pre-operative scrutiny resulted in upfront oncological surgery achieving cancer free margins, it afforded 100% recurrence free survival at 5- and 10-year follow-up, whilst failure to achieve clear margins caused significant burden by outpatient admissions (176 vs. 4 days; χ2 980, p < 0.001) and exposure to causes for concern (1369 vs. 0 days; χ2 11.3, p = 0.003). Although limited by cohort size, our study emphasizes the paradigm of getting it right the first time as key to improve survivorship in a cancer with excellent long-term prognosis.

Patterns and Predictors of Cervical Lymph Node Metastasis in Parathyroid Carcinoma

Simple Summary

Parathyroid carcinoma (PC) is a rare endocrine malignancy with poor outcomes. Surgery remains the mainstay of PC treatment. However, due to the rarity of this malignancy, the optimal extent of PC surgery remains inconclusive, including whether to perform central lymph node dissection (LND). In the present study, we reported the patterns and predictors of cervical lymph node metastasis in PC based on a cohort of 68 PC patients. The results showed that the percentage of cervical lymph node metastasis in PC was 19.4% at initial surgery and 25.0% including reoperations for recurrencies. High-risk Schulte staging and CDC73 abnormalities were identified as risk factors for cervical lymph node metastasis. Central LND should be considered during remedial surgeries performed after previous local resection of PC for patients with high risk factors.

Abstract

Background: Parathyroid carcinoma (PC) is a rare endocrine malignancy with poor outcomes. Over 60% of PC patients experience repeated disease recurrence or metastasis. The significance of cervical lymph node dissection (LND) for PC remains inconclusive. Methods: PC patients diagnosed at Peking Union Medical College Hospital between 1992 and 2021 were reviewed retrospectively. Clinical data, initial tumor histological staging, parafibromin histochemical staining results, Ki67 index, CDC73 gene mutation status and outcome information were collected systemically. The risk factors for recurrence and lymph node or distant metastasis were explored. Results: Sixty-eight PC patients receiving LND were enrolled. Cervical lymph node metastasis was identified in 19.4% of patients at initial surgery and 25.0% of patients including reoperations for recurrences. The independent risk factor for PC recurrence was a Ki67 index ≥ 5% (HR4.41, 95% confidence interval (CI)1.30–14.95, p = 0.017). Distant metastasis was an independent prognostic factor for PC patient overall survival (HR 5.44, 95% CI 1.66–17.82, p = 0.005). High-risk Schulte staging (p = 0.021) and CDC73 abnormalities (p = 0.012) were risk factors for cervical lymph node metastasis. Conclusion: Most PCs were slow-growing, but lymph node metastasis was not rare. For patients planning to undergo remedial surgery after previous local resection of PC, central LND is suggested for tumors with high-risk Schulte staging or CDC73 abnormalities.

Case series of diagnosis and surgery challenges in parathyroid carcinoma

INTRODUCTION

Parathyroid carcinoma (PC) is a rare malignancy that accounts for 1 % of cases of hyperparathyroidism. Data regarding PC in Indonesia are scarce, which poses challenges to diagnosis and treatment. This study aims to describe a series of PC cases from a tertiary health care center over 12 years.

PRESENTATION OF CASES

Retrospective data of six patients with hyperparathyroidism diagnosed with PC between 2008 and 2020 were reviewed. Clinical presentation, diagnosis, management, and short-term outcomes of PC were analyzed. All six PC patients were diagnosed postoperatively. Four of the patients presented with symptomatic hypercalcemia, and two presented with neck swelling. Elevated serum parathyroid hormone was observed in five patients. Only two patients had imaging results corresponding to PC characteristics. Ipsilateral parathyroidectomies were performed on 5 patients where invasion and metastasis are not evident. Four frozen section samples suggested PC, and two suggested parathyroid adenoma. Further histopathologic examination confirmed a diagnosis of PC in all patients. No metastasis to the adjacent lymph nodes or distant target organs was found during surgery.

DISCUSSION

Preoperative diagnosis of PC remains challenging. Suspicion of PC is appropriate in the presence of severe hypercalcemia, elevated parathyroid hormone level, and a mass observed either during imaging or intraoperatively.

CONCLUSION

Ipsilateral parathyroidectomy seems to be feasible compared to total resection in order to preserve function and structure. Incomplete excision may lead to an increased risk of recurrence, emphasizing the importance of routinely following up on PC cases.

The Long Non-Coding BC200 Is a Novel Circulating Biomarker of Parathyroid Carcinoma

Long non-coding RNAs (lncRNAs) are an important class of epigenetic regulators involved in both physiological processes and cancer development. Preliminary evidence suggested that lncRNAs could act as accurate prognostic and diagnostic biomarkers. Parathyroid cancer is a rare endocrine neoplasia, whose management represents a clinical challenge due to the lack of accurate molecular biomarkers. Our previous findings showed that human parathyroid tumors are characterized by a different lncRNAs signature, suggesting heterogeneity through the different histotypes. Particularly, we found that the lncRNA BC200/BCYRN1 could represent a candidate biomarker for parathyroid carcinomas (PCas). Here we aimed to extend our preliminary data evaluating whether BC200 could be an accurate non-invasive biomarker of PCas to support the clinical management of patients affected by parathyroid tumors at diagnosis, prognosis and follow-up. To provide a non-invasive point-of-care for parathyroid carcinoma diagnosis and follow-up, we analyzed BC200 expression in patients' serum through digital PCR. Our results show that BC200 counts are higher in serum from patients harboring PCa (n=4) compared to patients with parathyroid adenoma (PAd; n=27). Further, in PAd patients circulating BC200 levels are positively correlated with serum total calcium. Then, we found that BC200 is overexpressed in metastatic PCas (n=4) compared to non-metastatic ones (n=9). Finally, the lncRNA expression in PCa patients' serum drops are reduced after parathyroidectomy, suggesting its possible use in the post-operative setting for patients follow-up. Overall, these findings extend the knowledge on BC200 in parathyroid tumors, supporting its role as a useful biomarker for management of PCa.