Mohamed A. Adam

Extent of Surgery for Papillary Thyroid Cancer Is Not Associated with Survival: An Analysis of 61,775 Patients

Objective:To examine the association between the extent of surgery and overall survival in a large contemporary cohort of patients with papillary thyroid cancer (PTC). Background:Guidelines recommend total thyroidectomy for PTC tumors >1 cm, based on older data demonstrating an overall survival advantage for total thyroidectomy over lobectomy. Methods:Adult patients with PTC tumors 1.0–4.0 cm undergoing thyroidectomy in the National Cancer Database, 1998–2006, were included. Cox proportional hazards models were applied to measure the association between the extent of surgery and overall survival while adjusting for patient demographic and clinical factors, including comorbidities, extrathyroidal extension, multifocality, nodal and distant metastases, and radioactive iodine treatment. Results:Among 61,775 PTC patients, 54,926 underwent total thyroidectomy and 6849 lobectomy. Compared with lobectomy, patients undergoing total thyroidectomy had more nodal (7% vs 27%), extrathyroidal (5% vs16%), and multifocal disease (29% vs 44%) (all Ps < 0.001). Median follow-up was 82 months (range, 60–179 months). After multivariable adjustment, overall survival was similar in patients undergoing total thyroidectomy versus lobectomy for tumors 1.0–4.0 cm [hazard ratio (HR) = 0.96; 95% confidence interval (CI), 0.84–1.09); P = 0.54] and when stratified by tumor size: 1.0–2.0 cm [HR = 1.05; 95% CI, 0.88–1.26; P = 0.61] and 2.1–4.0 cm [HR = 0.89; 95% CI, 0.73–1.07; P = 0.21]. Older age, male sex, black race, lower income, tumor size, and presence of nodal or distant metastases were independently associated with compromised survival (P < 0.0001). Conclusions:Current guidelines suggest total thyroidectomy for PTC tumors >1 cm. However, we did not observe a survival advantage associated with total thyroidectomy compared with lobectomy. These findings call into question whether tumor size should be an absolute indication for total thyroidectomy.

Presence and Number of Lymph Node Metastases Are Associated With Compromised Survival for Patients Younger Than Age 45 Years With Papillary Thyroid Cancer

PURPOSE Cervical lymph node metastases are recognized as a prognostic indicator only in patients age 45 years or older with papillary thyroid cancer (PTC); patients younger than age 45 years are perceived to have low-risk disease. The current American Joint Committee on Cancer staging for PTC in patients younger than age 45 years does not include cervical lymph node metastases. Our objective was to test the hypothesis that the presence and number of cervical lymph node metastases have an adverse impact on overall survival (OS) in patients younger than age 45 years with PTC. PATIENTS AND METHODS Adult patients younger than age 45 years undergoing surgery for stage I PTC (no distant metastases) were identified from the National Cancer Data Base (NCDB; 1998-2006) and from SEER 1988-2006 data. Multivariable models were used to examine the association of OS with the presence of lymph node metastases and number of metastatic nodes. RESULTS In all, 47,902 patients in NCDB (11,740 with and 36,162 without nodal metastases) and 21,855 in the SEER database (5,188 with and 16,667 without nodal metastases) were included. After adjustment, OS was compromised for patients with nodal metastases compared with patients who did not have them (NCDB: hazard ratio (HR), 1.32; 95% CI, 1.04 to 1.67; P = .021; SEER: HR, 1.29; 95% CI, 1.08 to 1.56; P = .006). After adjustment, increasing number of metastatic lymph nodes was associated with decreasing OS up to six metastatic nodes (HR, 1.12; 95% CI, 1.01 to 1.25; P = .03), after which more positive nodes conferred no additional mortality risk (HR, 0.99; 95% CI, 0.99 to 1.05; P = .75). CONCLUSION Our results suggest that cervical lymph node metastases are associated with compromised survival in young patients, warranting consideration of revised American Joint Committee on Cancer staging. A change point of six or fewer metastatic lymph nodes seems to carry prognostic significance, thus advocating for rigorous preoperative screening for nodal metastases.

Is There a Minimum Number of Thyroidectomies a Surgeon Should Perform to Optimize Patient Outcomes

Objective: To determine the number of total thyroidectomies per surgeon per year associated with the lowest risk of complications. Background: The surgeon volume–outcome association has been established for thyroidectomy; however, a threshold number of cases defining a “high-volume” surgeon remains unclear. Methods: Adults undergoing total thyroidectomy were identified from the Health Care Utilization Project-National Inpatient Sample (1998–2009). Multivariate logistic regression with restricted cubic splines was utilized to examine the association between the number of annual total thyroidectomies per surgeon and risk of complications. Results: Among 16,954 patients undergoing total thyroidectomy, 47% had thyroid cancer and 53% benign disease. Median annual surgeon volume was 7 cases; 51% of surgeons performed 1 case/y. Overall, 6% of the patients experienced complications. After adjustment, the likelihood of experiencing a complication decreased with increasing surgeon volume up to 26 cases/y (P < 0.01). Among all patients, 81% had surgery by low-volume surgeons (⩽25 cases/y). With adjustment, patients undergoing surgery by low-volume surgeons were more likely to experience complications (odds ratio 1.51, P = 0.002) and longer hospital stays (+12%, P = 0.006). Patients had an 87% increase in the odds of having a complication if the surgeon performed 1 case/y, 68% for 2 to 5 cases/y, 42% for 6 to 10 cases/y, 22% for 11 to 15 cases/y, 10% for 16 to 20 cases/y, and 3% for 21 to 25 cases/y. Conclusions: This is the first study to identify a surgeon volume threshold (>25 total thyroidectomies/y) that is associated with improved patient outcomes. Identifying a threshold number of cases defining a high-volume thyroid surgeon is important, as it has implications for quality improvement, criteria for referral and reimbursement, and surgical education.

Surgeon-Performed Ultrasound Is Superior to 99Tc-Sestamibi Scanning to Localize Parathyroid Adenomas in Patients with Primary Hyperparathyroidism: Results in 516 Patients over 10 Years

BACKGROUND Surgeon-performed cervical ultrasound (SUS) and 99Tc-sestamibi scanning (MIBI) are both useful in patients with primary hyperparathyroidism (PHPT). We sought to determine the relative contributions of SUS and MIBI to accurately predict adenoma location. STUDY DESIGN We performed a database review of 516 patients undergoing surgery for PHPT between 2001 and 2010. SUS was performed by 1 of 3 endocrine surgeons. MIBI used 2-hour delayed anterior planar and single-photon emission computerized tomography images. Directed parathyroidectomy was performed with extent of surgery governed by intraoperative parathyroid hormone decline of 50%. RESULTS SUS accurately localized adenomas in 87% of patients (342/392), and MIBI correctly identified their locations in 76%, 383/503 (p < 0.001). In patients who underwent SUS first, MIBI provided no additional information in 92% (144/156). In patients who underwent MIBI first, 82% of the time (176/214) SUS was unnecessary (p = 0.015). In 32 patients SUS was falsely negative. The reason for these included gland location in either the deep tracheoesophageal groove (n = 9) or the thyrothymic ligament below the clavicle (n = 5), concurrent thyroid goiter (n = 4), or thyroid cancer (n = 1). In 13 cases, the adenoma was located in a normal ultrasound-accessible location but was missed by the preoperative exam. In the 32 ultrasound false-negative cases, MIBI scans were positive in 21 (66%). Of the 516 patients, 7.6% had multigland disease. Persistent disease occurred in 4 patients (1%) and recurrent disease occurred in 6 (1.2%). CONCLUSIONS When performed by experienced surgeons, SUS is more accurate than MIBI for predicting the location of abnormal parathyroids in PHPT patients. For patients facing first-time surgery for PHPT, we now reserve MIBI for patients with unclear or negative SUS.

Impact of extent of surgery on survival for papillary thyroid cancer patients younger than 45 years.

CONTEXT Papillary thyroid cancer (PTC) patients <45 years old are considered to have an excellent prognosis; however, current guidelines recommend total thyroidectomy for PTC tumors >1.0 cm, regardless of age. OBJECTIVE Our objective was to examine the impact of extent of surgery on overall survival (OS) in patients <45 years old with stage I PTC of 1.1 to 4.0 cm. DESIGN, SETTING, AND PATIENTS Adult patients <45 years of age undergoing surgery for stage I PTC were identified from the National Cancer Data Base (NCDB, 1998-2006) and the Surveillance, Epidemiology, and End RESULTS dataset (SEER, 1988-2006). MAIN OUTCOME MEASURE Multivariable modeling was used to compare OS for patients undergoing total thyroidectomy vs lobectomy. RESULTS In total, 29 522 patients in NCDB (3151 lobectomy, 26 371 total thyroidectomy) and 13 510 in SEER (1379 lobectomy, 12 131 total thyroidectomy) were included. Compared with patients undergoing lobectomy, patients having total thyroidectomy more often had extrathyroidal and lymph node disease. At 14 years, unadjusted OS was equivalent between total thyroidectomy and lobectomy in both databases. After adjustment, OS was similar for total thyroidectomy compared with lobectomy across all patients with tumors of 1.1 to 4.0 cm (NCDB: hazard ratio = 1.45 [confidence interval = 0.88-2.51], P = 0.19; SEER: 0.95 (0.70-1.29), P = 0.75) and when stratified by tumor size: 1.1 to 2.0 cm (NCDB: 1.12 [0.50-2.51], P = 0.78; SEER: 0.95 [0.56-1.62], P = 0.86) and 2.1 to 4.0 cm (NCDB: 1.93 [0.88-4.23], P = 0.10; SEER: 0.94 [0.60-1.49], P = 0.80). CONCLUSIONS After adjusting for patient and clinical characteristics, total thyroidectomy compared with thyroid lobectomy was not associated with improved survival for patients <45 years of age with stage I PTC of 1.1 to 4.0 cm. Additional clinical and pathologic factors should be considered when choosing extent of resection.

Severe obesity is associated with symptomatic presentation, higher parathyroid hormone levels, and increased gland weight in primary hyperparathyroidism.

CONTEXT A relationship between primary hyperparathyroidism (PHPT) and obesity has been observed but is incompletely understood. Furthermore, obesity has been associated with vitamin D deficiency, suggesting that the three conditions may be linked. OBJECTIVE We hypothesized that PHPT in morbidly obese patients is more severe and that the difference may be explained by vitamin D deficiency. DESIGN AND SETTING, PARTICIPANTS, AND OUTCOME MEASURES: Records of 196 patients with surgically treated PHPT and known body mass index (BMI) were examined. Patients were stratified into three BMI groups: group I (nonobese), BMI < 25 kg/m(2) (n = 54); group II (non-severely obese), BMI 25-34 kg/m(2) (n = 102); and group III (severely obese), BMI 35 kg/m(2) or greater (n = 40). RESULTS Preoperative PTH levels were higher in group ΙΙΙ compared with group Ι (181 ± 153 vs. 140 ± 80 pg/ml, p = 0.04). Group III patients had larger tumors on average compared with group I (1.8 ± 1.5 vs. 1.04 ± 1.5 g, P = 0.0002). In group III, BMI positively correlated with parathyroid tumor weight (r = 0.5, P = 0.002). Postoperative PTH was higher in group III compared with group Ι (61 ± 41 vs. 44 ± 28 pg/ml, P = 0.02). There was higher frequency of depression, musculoskeletal symptoms, weakness, and gastroesophageal reflux disease in group III patients. CONCLUSIONS BMI positively correlated with parathyroid tumor weight independent of vitamin D. Severely obese patients have larger parathyroid tumor weight, higher pre- and postoperative PTH, and greater symptoms.

Parathyroid Carcinoma: Current Understanding and New Insights into Gene Expression and Intraoperative Parathyroid Hormone Kinetics

Parathyroid carcinoma is an indolent but ultimately life-threatening malignancy. Due to the lack of definitive diagnostic markers and overlapping clinical features of benign primary hyperparathyroidism (PHPT), this disease is often misdiagnosed as parathyroid adenoma. Therefore, a high index of suspicion preoperatively and early intraoperative recognition with en bloc surgical resection are crucial for favorable outcome. Owing to the rarity of the disease, little is known about the molecular pathogenesis of parathyroid carcinoma. Here, we review the literature to present current understanding of the disease and provide new information on gene expression and use of intraoperative parathyroid hormone (PTH) monitoring in the surgical management of this rare malignancy. Specifically, using microarray transcriptome analysis of an unequivocal case of parathyroid carcinoma and a biopsy from the same patients normal parathyroid gland, we identify APP, CDH1, KCNJ16, and UCHL1 as differentially expressed genes in parathyroid carcinoma. Further, using case records from four cases of unequivocal parathyroid carcinoma, we compared intraoperative PTH kinetics of these patients to 475 patients with benign PHPT, and show that intraoperative PTH monitoring is accurate in predicting postoperative normocalcemia in initial en bloc operations for parathyroid carcinoma.

Extrathyroidal Extension Is Associated with Compromised Survival in Patients with Thyroid Cancer

BACKGROUND Patients with thyroid cancer who have extrathyroidal extension (ETE) are considered to have more advanced tumors. However, data on the impact of ETE on patient outcomes remain limited. The purpose of this study was to evaluate the association between ETE and survival in patients with thyroid cancer. METHODS The National Cancer Database (1998-2012) was queried for all adult patients with differentiated thyroid cancer and medullary thyroid cancer. Patients were divided into three groups: no ETE (T1 and T2 tumors), minimal ETE (T3 tumors <4 cm), and extensive ETE (T4 tumors <4 cm). Patient demographic, clinical, and pathologic factors were evaluated for all patients. A Cox proportional hazards model was developed for each histology to identify factors associated with survival. RESULTS In total, 241,118 patients with differentiated thyroid cancer met the inclusion criteria; 86.9% had no ETE, 9.1% minimal ETE, and 4.0% extensive ETE. Compared with patients with no ETE, patients with minimal and extensive ETE were more likely to have larger tumors (1.4 cm vs. 1.8 cm and 2.0 cm, respectively), lymphovascular invasion (8.6% vs. 28.0% and 35.1%, respectively), positive margins after thyroidectomy (6.1% vs. 35.2% and 45.9%, respectively), and regional lymph node metastases (32.5% vs. 67.0% and 74.6%, respectively; all p < 0.01). After adjustment, minimal ETE (hazard ratio [HR] = 1.13; p < 0.01) and extensive ETE (HR = 1.74; p < 0.01) were associated with compromised survival for patients with differentiated thyroid cancer. In total, 3415 patients with medullary thyroid cancer met the inclusion criteria; 87.9% had no ETE, 7.1% minimal ETE, and 5.0% extensive ETE. Compared with patients with no ETE, patients with minimal and extensive ETE were more likely to have larger tumors (1.7 cm vs. 2.2 cm and 2.2 cm, respectively), lymphovascular invasion (19.2% vs. 68.9% and 79.3%, respectively), positive margins after thyroidectomy (5.8% vs. 44.1% and 51.9%, respectively), and regional lymph node metastases (39.0% vs. 90.5% and 94.4%, respectively; all p < 0.01). After adjustment, extensive ETE (HR = 1.63; p = 0.01) was associated with compromised survival for patients with medullary thyroid cancer. CONCLUSION In patients with differentiated and medullary thyroid cancers, ETE is associated with compromised survival. Given these findings, ETE should be included in the thyroid cancer treatment guidelines.

Regulator of G Protein Signaling 5 Is Highly Expressed in Parathyroid Tumors and Inhibits Signaling by the Calcium-Sensing Receptor

The molecular mechanisms responsible for aberrant calcium signaling in parathyroid disease are poorly understood. The loss of appropriate calcium-responsive modulation of PTH secretion observed in parathyroid disease is commonly attributed to decreased expression of the calcium-sensing receptor (CaSR), a G protein-coupled receptor. However, CaSR expression is highly variable in parathyroid adenomas, and the lack of correlation between CaSR abundance and calcium-responsive PTH kinetics indicates that mechanisms independent of CaSR expression may contribute to aberrant calcium sensing in parathyroid disease. To gain a better understanding of parathyroid tumors and the molecular determinants that drive parathyroid adenoma development, we performed gene expression profiling on a panel of 64 normal and neoplastic parathyroid tissues. The microarray data revealed high-level expression of genes known to be involved in parathyroid biology (PTH, VDR, CGA, CaSR, and GCM2). Moreover, our screen identified regulator of G protein signaling 5 (RGS5) as a candidate inhibitor of CaSR signaling. We confirmed RGS5 to be highly expressed in parathyroid adenomas relative to matched-pair normal glands. Transient expression of RGS5 in cells stably expressing CaSR resulted in dose-dependent abrogation of calcium-stimulated inositol trisphosphate production and ERK1/2 phosphorylation. Furthermore, we found that RGS5-nullizygous mice display reduced plasma PTH levels, an outcome consistent with attenuated opposition to CaSR activity. Collectively, these data suggest that RGS5 can act as a physiological regulator of calcium sensing by CaSR in the parathyroid gland. The abnormally elevated expression of RGS5 observed in parathyroid adenomas could thus represent a novel mechanism of CaSR desensitization in patients with primary hyperparathyroidism.

Exploring the Relationship Between Patient Age and Cancer-Specific Survival in Papillary Thyroid Cancer: Rethinking Current Staging Systems

Purpose Patient age is considered to play a unique prognostic role in papillary thyroid cancer (PTC), with a distinct staging dichotomization at 45 years of age. This is based on older, limited data demonstrating a marked rise in mortality around the ages of 40 to 50 years. We hypothesized that age is associated with compromised survival from cancer, with no cutoff denoting survival difference. Patients and Methods Patients with PTC who had surgery were identified from the SEER database (1998 to 2012). Multivariable proportional hazards modeling utilizing several flexible smoothing approaches were used to examine the association between age and cancer-specific survival (CSS) and to determine whether there is an age cut point that is associated with CSS decrement. Results A total of 31,802 patients with PTC were included. Median age was 45 years (range, 2 to 105 years). Ten-year CSS according to age was as follows: 2 to 19 years, 99.8%; 20 to 29 years, 99.9%; 30 to 39 years, 99.8%; 40 to 49 years, 99.5%; 50 to 59 years, 98.1%; 60 to 69 years, 94.8%; 70 to 79 years, 91.5%; 80 to 89 years, 79.2%; and ≥ 90 years, 73.9%. After adjustment for patient demographic and clinicopathologic characteristics, increasing age was associated with increasing mortality from the disease in a dose-dependent fashion, without an apparent cut point. Each of the smoothing approaches demonstrated a similar linearity of risk over all ages and provided close measures of goodness of fit to the data. Conclusion Patient age is significantly associated with death from PTC in a linear fashion, without an apparent age cut point demarcating survival difference. These results challenge the appropriateness of a patient age cut point in current staging systems for PTC and argue for considering a revision in how we anticipate prognosis for patients with PTC.