Risk Factors for Distant Metastasis in Patients with Follicular Thyroid Carcinoma / 대한내분비외과학회지

PURPOSE: The major issue of follicular thyroid carcinoma (FTC) diagnosed after hemithyroidectomy is whether to undergo further treatments. The aim of this study is to examine the clinico-pathological characteristics of FTC and to evaluate the risk factors for distant metastasis. METHODS: From 1993 to 2010, 274 patients underwent initial thyroid surgery and were subsequently diagnosed as FTC. After review of the histological sections by an experienced pathologist, 211 patients were confirmed as FTC and were enrolled in this study. Clinicopathological features were compared based on the presence or absence of distant metastases, and the risk factors for distant metastases and distant metastases-free survival (DMFS) rates were analyzed. RESULTS: The patients included 39 males (18.5%) and 172 females (81.5%), with a mean age of 44.0±14.5 years. The median follow-up period was 99.5 months (range, 13.0~222.0). Distant metastases were detected in 23 patients (10.9%), including 15 synchronous distant metastases and 8 metachronous distant metastases. In multivariate analysis, age ≥45 years, widely invasive FTC, tumor size ≥4.3 cm, and vascular invasion were independent risk factors for distant metastasis. DMFS rates in patients with these risk factors were significantly poorer than those in patients without these risk factors. CONCLUSION: Older age, aggressive histological classification, larger tumor size, and vascular invasion were independent risk factors for distant metastasis. FTC patients with these risk factors may be candidates for further treatments after diagnostic thyroid hemithyroidectomy.

Clinical Meaning of Neutrophil-to-Lymphocyte Ratio (NLR)in Papillary Thyroid Carcinoma / 대한내분비외과학회지

PURPOSE: Neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammatory response, which is inexpensive, easily calculated, and known to show correlation with prognosis of cancer. The aim of this study was to evaluate the relationship between NLR and prognosis of papillary thyroid carcinoma. METHODS: A total of 1,142 patients who underwent total thyroidectomy for papillary thyroid carcinoma between 1995~2005 at Asan Medical Center were enrolled in this study. Patients were categorized according to two groups based on NLR and clinico-pathological variables and disease survival were compared between the two groups. RESULTS: Median age of patients was 45.4 years, and the median follow-up period was 48 months. The cut-off value of NLR for prediction of disease-free survival (DFS) was 2. Comparison of DFS between two groups stratified by NLR (NLR ≤2, NLR>2) showed little statistical difference (P=0.48). After adjusting for risk (N stage), there was no significant difference according to N stage (N0: P=0.86, N1a: P=0.4, N1b: P=0.12). CONCLUSION: NLR did not show correlation with disease free survival of papillary thyroid carcinoma.

Association between Serum Gamma-Glutamyl Transferase and Thyroid Cancer in an Ultrasonographically Screened Population / 대한갑상선학회지

BACKGROUND AND OBJECTIVES: We reported recently a positive correlation between obesity and thyroid cancer in women. Serum gamma-glutamyl transferase (GGT) is regarded as a marker of exposure to environmental pollutants, cancer-causing xenobiotic. This study was conducted to evaluate the mechanism behind the association of obesity with thyroid cancer. We hypothesized serum GGT may be a surrogate for persistent organic pollutants to explain the connection between obesity and thyroid cancer. MATERIALS AND METHODS: We obtained data from 15,131 subjects who underwent a routine health checkup including thyroid ultrasonography from 2007 to 2008 at the Health Screening and Promotion Center of Asan Medical Center. Suspicious nodules were examined by ultrasonography-guided aspiration. Those with a history of hepatobiliary disease and abnormal result of liver function test were excluded. Serum GGT cut-off points were the 25th, 50th, and 75th sex-specific percentiles. RESULTS: A total of 15,131 subjects (7662 men and 7469 women) were screened by thyroid ultrasonography. Thyroid cancers were diagnosed in 260 patients. After adjustment of age, smoking status, alcohol intake, body mass index, compared with the lowest serum GGT quartile, odds ratios (95% confidence intervals) of risk of thyroid cancer were 0.54 (0.28-0.99) for 2nd quartile, 0.92 (0.56-1.50) for 3rd quartile, and 0.61 (0.34-1.09) for 4th quartile in men. In women, the adjusted odds ratios were 1.06 (0.66-1.72), 1.18 (0.77-1.85), and 0.63 (0.38-1.06) for the 2nd, 3rd, and 4th quartile, respectively. CONCLUSION: Elevated GGT is not associated with a higher prevalence of thyroid cancer in either gender when evaluated in a routine health checkup setting.

Lack of Associations between Body Mass Index and Clinical Outcomes in Patients with Papillary Thyroid Carcinoma

BACKGROUND: Obesity is associated with aggressive pathological features and poor clinical outcomes in breast and prostate cancers. In papillary thyroid carcinoma (PTC), these relationships remain still controversial. This study aimed to evaluate the associations between body mass index (BMI) and the clinical outcomes of patients with PTC. METHODS: This retrospective study included 1,189 patients who underwent total thyroidectomy for PTCs equal to or larger than 1 cm in size. Clinical outcomes were evaluated and compared based on the BMI quartiles. RESULTS: There were no significant associations between BMI quartiles and primary tumor size, extrathyroidal invasion, cervical lymph node metastasis, or distant metastasis. However, an increase in mean age was associated with an increased BMI (P for trend <0.001). Multifocality and advanced tumor-node-metastasis (TNM) stage (stage III or IV) were significantly associated with increases of BMI (P for trend 0.02 and <0.001, respectively). However, these associations of multifocality and advanced TNM stage with BMI were not significant in multivariate analyses adjusted for age and gender. Moreover, there were no differences in recurrence-free survivals according to BMI quartiles (P=0.26). CONCLUSION: In the present study, BMI was not associated with the aggressive clinicopathological features or recurrence-free survivals in patients with PTC.

Time Trends Analysis of Characteristics of Patients with Thyroid Cancer in a Single Medical Center / 대한갑상선학회지

BACKGROUND AND OBJECTIVES: The incidence of thyroid cancer is increasing worldwide. The increase in the frequency of screening tests may have led to an over-detection of small thyroid cancers. The Korean Thyroid Association (KTA) discourages the find needle aspiration of thyroid nodules < or =0.5 cm. The aim of this study was to evaluate time trends of characteristics of thyroid cancer patients in a single medical center. MATERIALS AND METHODS: This study included 15,465 patients who underwent operation due to thyroid cancer from 1995 to 2012. Data on age, gender of patients and histology, clinical stage of the thyroid cancer were reviewed retrospectively. RESULTS: New thyroid cancer cases have dramatically increased and papillary thyroid carcinoma (PTC) accounted for a major part of this increase. PTCs were accounted for 98% of all thyroid cancer surgeries in 2012 and 79% in 1995. The proportion of PTCs < or =0.5 cm has increased from 1% in 1995 to 32% in 2009 and then slightly decreased afterward. The peak age of patients with PTC has increased from 40 years in 1995-2000 to 55 years in 2006-2012. The proportion of small follicular thyroid carcinomas and medullary thyroid carcinomas (< or =1.0 cm) also steadily increased during study periods. CONCLUSION: Thyroid cancers became smaller but, increase of very small PTCs stopped after 2010, in which the KTA guidelines were introduced. These findings suggest that the increasing incidence of thyroid cancer in Korea might be due to the over-detection of small thyroid cancers.

Definition and Prognostic Factor of Minimally Invasive Follicular Thyroid Carcinoma / 대한내분비외과학회지

Minimally invasive follicular thyroid carcinoma (MIFTC) is a subtype of follicular thyroid carcinoma. The definition of MIFTC is somewhat confusing; as a result, diagnosis of MIFTC is difficult. MIFTC is known to have an excellent prognosis. Thus, no further treatment is usually required after diagnostic lobectomy. However, some patients with MIFTC experience distant metastasis after initial lobectomy. In this review, we will discuss the definition of MIFTC and risk factors of distant metastasis after initial lobectomy.

A Case Report of Papillary Thyroid Carcinoma Presenting as Elevated Serum CA 19-9 / 대한내과학회지

A 47-year-old man had elevated serum CA 19-9 after a routine health check-up. He had normal CA 19-9 levels during the preceding 8 years on annual heath checks. Imaging studies for pancreatic or biliary tract diseases revealed no abnormalities. A huge hypermetablic lesion was found in the right lobe of the thyroid on 18F-fluorodeoxyglucose positron emission tomography/computed tomography. We performed a fine needle aspiration of the thyroid nodule. He was diagnosed with papillary thyroid carcinoma and underwent a total thyroidectomy with a modified radical neck dissection. Serum CA 19-9 level decreased to the normal range after surgery. Although there have been few reports of patients with elevated serum CA 19-9 levels due to papillary thyroid carcinoma, this is the first report showing such an association in Korea. Thyroid cancer should be considered when the causes of elevated serum CA 19-9 are unclear.

Surgical Extent of Thyroidectomy for Papillary Thyroid Microcarcinoma / 대한내분비외과학회지

The incidence of PTMC (papillary thyroid microcarcinoma) has rapidly increased recently due to the application of ultrasonography to the thyroid. The good prognosis of PTMC is well known with a mortality rate of less than 1%. However, there is controversy about the surgical extent of thyroidectomy for PTMC patients between surgeons and endocrinologists due to differences in understanding the clinical properties of PTMC, while having a difference in basic concepts in the treatment and follow up strategy for PTMC patients. Total thyroidectomy is recommended for PTMC patients because there is no major difference in the rate of lymph node metastasis, extrathyroidal extension, multiplicity between the PTMC and PTC over 1 cm in size and although rare, occasional distant metastasis and mortality cases could be developed. However, there is no evidence of benefit of total thyroidectomy for the survival rate of PTMC patients. The microscopic lymph node metastasis and extrathyroidal extension are not prognostic factors for the survival or recurrence in PTMC. The clinical lateral neck lymph node metastasis and multiplicity has been proposed as valuable prognostic factors in micropapillary carcinoma and these factors could be assessed accurately by ultrasonography preoperatively. A decision on the proper extent of thyroidectomy could be possible in most PTMC patients. This article summarizes available data and concludes that routine total thyroidectomy for PTMC patients is not rational.

Recurred Parathyroid Carcinoma: A Case of Cervical Recurrence Presenting Discrepancy between Image Findings and Operative Findings / 대한내분비외과학회지

Parathyroid carcinoma is a rare malignancy presenting hyperparathyroidism. At times, diagnosis and localization are difficult. The optimum treatment for parathyroid carcinoma is en bloc resection when malignancy is highly suspicious or diagnosed. However, even after the adequate surgical treatment, persistent or recurrent disease is well encountered. Here we report a case with recurred parathyroid carcinoma presenting discrepancy between image findings and operative findings.

Comparison of Different Staging Systems for Predicting Recurrence of Papillary Thyroid Carcinoma

BACKGROUND: Various staging systems for thyroid cancer that focus on cancer specific death have been suggested, but this approach had a limitation due to the relatively long clinical course and very low rate of cancer death. This study was performed to evaluate the staging systems and to determine the most predictive staging system for predicting recurrence. METHODS: The patients who underwent first total or near total thyroidectomy due to papillary thyroid cancer (PTC) at Asan Medical Center between January 1995 and December 2001 were the subjects of this study. The commonly used 8 staging systems were applied to these subjects. Disease free survival (DFS) and the relative importance of each staging system were determined by the Kaplan-Meier method, the Cox-proportional hazards model and the proportion of variation in the survival time explained (PVE). RESULTS: A total of 952 patients (M = 117, F = 835) were enrolled and their mean age was 45 years. During a median of 10 years of follow-up, 146 (15.3%) of 952 patients had recurred tumor. The independent prognostic factors were male gender, tumor size, extrathyroidal invasion and cervical lymph node metastasis. Risk stratification according to the American thyroid association (ATA) guideline was the most predictive staging system for recurrence of PTC (PVE 88.6%). The staging systems from EORTC (PVE 79.5%), and MACIS (PVE 68.4%) had significant values for predicting recurrence of PTC. The stage of NTCTCS could not predict recurrence (PVE 4.5%, P = 0.11). CONCLUSION: Risk stratification according to the ATA was most predictive staging system for predicting recurrence of PTC. The MACIS and EORTC staging systems have good value for predicting recurrence of PTC.

Expression of X-linked Inhibitor of Apoptosis Protein in Neoplastic Thyroid Disorder

X-linked inhibitor of apoptosis protein (XIAP) is associated with tumor genesis, growth, progression and metastasis, and acts by blocking caspase-mediated apoptosis. In the present study, we sought to evaluate the expression patterns of XIAP in various neoplastic thyroid disorders and determine the association between XIAP expression and clinicopathologic factors. Expression of XIAP was evaluated with immunohistochemical staining using monoclonal anti-XIAP in 164 specimens of conventional papillary thyroid carcinoma (PTC) and 53 specimens of other malignant or benign thyroid tumors. XIAP positivity was observed in 128 (78%) of the 164 conventional PTC specimens. Positive rates of XIAP expression in follicular variant PTC, follicular, medullary, poorly differentiated, and anaplastic thyroid carcinoma specimens were 20%, 25%, 38%, 67%, and 38%, respectively. Six nodular hyperplasia specimens were negative and 1 of 7 follicular adenomas (8%) was positive for XIAP. Lateral neck lymph node metastases were more frequent in patients negative for XIAP expression (P = 0.01). Immunohistochemical staining for XIAP as a novel molecular marker may thus be helpful in the differential diagnosis of thyroid cancer. Moreover, high XIAP expression in conventional PTC is strongly associated with reduced risk of lateral neck lymph node metastasis.

Postoperative Findings of the Cytological Diagnosis of Follicular Neoplasm or Hurthle Cell Neoplasm and the Risk of Malignancy

BACKGROUND: Follicular neoplasm (FN) or Hurthle cell neoplasm (HN) is a less well understood pitfall when evaluating thyroid nodule with fine-needle aspiration (FNA). This study aimed to determine the rates of malignancy and the predictive factors for malignancy in thyroid nodules with a cytological diagnosis of FN or HN. METHODS: The patients who were cytologically diagnosed as having FN or HN after FNA between 1995 and 2004 at Asan Medical Center were included in this study. We collected the pathology data until 2009 and we analyzed the clinical characteristics associated with malignancy. RESULTS: A total 478 patients were cytologically diagnosed as having FN or HN during the study period and 327 (68%) among them underwent thyroid surgery. Thyroid malignancy was confirmed in 157 (48%) of 327 patients. Malignancy was confirmed in 124 patients with FN (124/253, 49%). They were 48 papillary, 65 follicular, 7 Hurthle cell and 3 medullary carcinomas and 1 anaplastic carcinoma. The malignancy in the cases of HN (33/71, 44.6%) was 9 papillary, 4 follicular and 20 Hurthle cell carcinomas. The risk of malignancy was not associated with male gender, a larger tumor size (> 4 cm) or the diagnosis of HN. However, an age below 20 years (RR 3.6, P = 0.03) and above 60 years (RR 2.3, P = 0.04) was associated with an increased risk of malignancy. CONCLUSION: About half of the patients with FN or HN on FNA cytology were diagnosed as having thyroid cancer after surgery. The malignancy rate for the cytologic diagnosis of HN was similar to that for FN. Thyroid surgery should be recommended for this situation, and especially for patients younger than 20 years or older than 60 years.

Factors Influencing Peripheral Conversion of Thyroxine to Tri-Iodothyronine in Athyreotic Individuals during Levothyroxine Replacement

BACKGROUND: Tri-iodothyronine (T3) is the main active hormone, and 20% of this is derived from the thyroid gland and 80% is from the peripheral tissue according to 5'-monodeiodination of thyroxine (T4). In the previous studies, normal T3 levels were achieved with traditional levothyroxine (LT4) therapy alone in athyreotic patients, but there has been no data about the factors influencing peripheral conversion of LT4. The aim of this study was to determine the factor(s) influencing peripheral conversion of LT4 to T3 in athyreotic patients during LT4 replacement. METHODS: The patients who underwent total-thyroidectomy for any cause, and mostly for thyroid cancers, at Asan Medical Center between 2000 and 2008 were enrolled. The free T4, T3 and thyroid stimulating hormone (TSH) levels and age, gender, weight, height, body mass index (BMI) and the T4 dose were measured. Only patients with normal ranges of free T4 and TSH were included in the analysis. RESULTS: A total of 143 patients were enrolled. The mean T3, free T4 and TSH levels were 143.7 ng/dL, 1.4 ng/dL and 1.6 microU/mL, respectively. The mean weight and BMI were 62.9 kg and 24.6 kg/m2, respectively. We divided them into two groups according to the serum T3 level and we compared the characteristics of the groups. There were no differences in age, the gender distribution, the T4 dose/weight and the BMI between the low T3 group (T3 122 ng/dL, n = 129). In the low T3 group, the mean body weight was significantly lower than that of the normal T3 group (59.0 +/- 6.0 vs. 63.4 +/- 9.9, respectively, P = 0.025). CONCLUSION: Lean body mass seems to be an important factor for determining the peripheral conversion of T4 to T3 in human. This suggest that a combination of T3/T4 is better than T4 only when we treat the patients with hypothyroidism and who have a negligible amount of functioning thyroid tissue, if they have a low lean body mass.

DNA Copy Number Changes in Thyroid Medullary Carcinomas Determined by Comparative Genomic Hybridization

BACKGROUND: A point mutation in the RET proto-oncogene, in medullary thyroid carcinoma (MTC) is well known, but no other genetic causes of MTC have been found. This study was performed to identify the most common DNA copy number changes in MTC by comparative genomic hybridization (CGH). METHODS: Twenty-nine surgically resected MTC specimens were retrospectively selected from patients operated on between 1996 and 2004 at the Asan Medical Center. A review of the clinical data and pathological findings was performed. Congored staining and immunohistochemical stains (calcitonin, chromogranin A and CEA) were processed by tissue microarray. CGH analysis was performed. RESULTS: The Congo-red stain was positive in only 12 cases. The immunohistochemical results were positive in 29 cases for chromogranin A, 26 cases for CEA and 25 cases for calcitonin. DNA copy number changes were found in 23 cases (79.3%). The most frequent change was a gain of 19q (65.5%); less frequent changes were gain of 22 (55.2%), 19p (51.7%), 16p (27.58%), 17q (17.24%), and loss of 4q (27.6%) and 3p (17.24%). CONCLUSIONS: DNA copy number changes of MTC were more common (79.3%) than reported in previous studies. The most frequent changes were gains in 19q, 22 and 19p.

Role of 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside in the Growth Regulation of Anaplastic Thyroid Cancer Cells Lines / 대한내분비학회지

BACKGROUND: Anaplastic thyroid carcinoma is one of the most aggressive human cancers with a median survival of only 6 months. Local surgical tumor debulking combined with radio-chemotherapy is generally used to treat this malady, but the low success rate has prompted the search for new therapeutic targets. We used 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) as an AMP-activated protein kinase (AMPK) activator to induce growth suppression and apoptosis in the anaplastic thyroid carcinoma cells. METHODS: We investigated the effect of AICAR on the proliferation of thyroid cancer cell lines (ARO, WRO and FRO) by performing methyl-thiazoletetrazolium bromide assay. We wanted to see the effect of AICAR on the apoptosis and cell cycle of the thyroid cancer cells, and we wanted to determine the mechanism of these changes. RESULTS: The proliferation of all thyroid cancer cell lines was significantly inhibited by administration of AICAR. FRO was the most susceptible cell line to AICAR treatment and so further studies were then performed with this cell line. The suppressive effect of AICAR on cell proliferation was related with phosphorylation of AMPK and the increased apoptosis. Also, cell cycle analysis revealed that progression to the G2-M phase was arrested (S-phase arrest) by AICAR treatment. S-phase arrest was associated with the increased protein expression of p21. CONCLUSION: In the anaplastic thyroid cancer cell lines, AICAR inhibited proliferation due to the arrest in the S-phase; this was accompanied with the increased expression of p21. Overall, AMPK activation by AICAR or any other pharmacological agent could be a tempting potential target for thyroid cancer therapy.

The Risk Factors of Hypocalcemia after Total Thyroidectomy: What is the Main Cause of Transient Hypocalcemia? / 대한내분비외과학회지

PURPOSE: Parathyroid injury and metabolic events are known causes of post thyroidectomy hypocalcemia and many other clinical risk factors are also noted. This retrospective study was undertaken to determine the main causative factor of transient hypocalcemia after total thyroidectomy. METHODS: 237 patients underwent total thyroidectomy and 10 patients underwent lobectomy were enrolled in this study. The incidence of transient and permanent hypocalcemia was investigated and we evaluate the risk factors. In 36 patients who underwent total thyroidectomy and 10 patients who underwent lobectomy, serum total calcium and, ionized calcium, i-PTH were measured at post operative day 1, 3, 7 and compared according to the number of preserved parathyroid glands. RESULTS: The incidence of transient and permanent hypocalcemia after total thyroidectomy was 3.4% (8/237) and 0.4% (1/237) respectively. Among the investigated risk factors, the number of preserved parathyroid gland was the only significant factor for hypocalcemia and, tumor extent, extent of central lymph node dissection and, lateral lymph node dissection were not the significant risk factors. The incidence of hypocalcemia was closely related to the number of preserved parathyroid gland (0 (66.7%), 1 (5.2%), 2 (0.7%), 3 (0%), 4 (0%))(P<0.001). The levels of serum total calcium, ionized calcium and, i-PTH were significantly different between the patients in whom only 1 parathyroid gland was preserved and more than 1 gland preserved at post operative day 1, 3. However there was no difference between two groups at post operative day 7. CONCLUSION: The technical aspect of parathyroid preservation is the most important factor for post thyroidectomy hypocalcemia.

Clinical Manifestation of Multiple Endocrine Neoplasia Type I / 대한내분비외과학회지

PURPOSE: Multiple endocrine neoplasia type I is rarely reported in Korea. The purpose of this study is to analyze the clinical features and the treatment of MEN1 which had been carried out in our institution. METHODS: Eight patients underwent surgery for MEN1-related hyperparathyroidism, duodenopancreatic tumors and pituitary tumors at our institution and were reviewed retrospectively. RESULTS: Of the eight patients, all patients had hyperparathyroidism. There were 5 total parathyroidectomy patients and 3 subtotal parathyroidectomy patients, none of them had persistent and recurrent hyperparathyroidism after operation. However, one of total parathyroidectomy patients had persistent hypoparathyroidism. Of the 8 patients, seven had duodenopancreatic tumors; four of them had pancreatic islet-cell tumors, two had malignant gastrinoma and one had Zollinger-Ellision syndrome. Pituitary tumors were observed in 6 patients among the 8; four of them had prolactinoma, and 2 had adenoma which was confirmed by magnetic resonance imaging. Of the eight patient, only one patient was confirmed to have another MEN1 family member and the mutation of MEN1 gene on chromosome 11q13 was proved on gene study. CONCLUSION: The clinical features of these patients were similar to those in other reports and the results of surgical treatment were relatively satisfactory. However, the detection of other MEN1 patients among the family members was relatively poor. Close follow up of family members and gene study will be required.

Long-term Follow-up of Patients with Elevated PTH Levels after Operation for Primary Hyperparathyroidism / 대한내분비외과학회지

PURPOSE: Elevation of serum parathyroid hormone (PTH) with normocalcemia after parathyroidectomy for primary hyperparathyroidism (pHPT) has been documented. This study was performed to investigate the factors correlated with elevated PTH level after surgery. METHODS: Twenty-one patients who underwent successful parathyroidectomy for pHPT had elevated postoperative serum PTH level despite normocalcemia. Patients were categorized into 2 groups based on their serum PTH level: patients who had fluctuation between normal and elevated PTH (group 1, n=12) and patients with early elevated PTH levels, and then normalized during follow up (group 2, n=6). Serum level of PTH, total calcium, ionized calcium, alkaline phosphatase, creatinine, vitamin D, osteocalcin and bone densitometry were compared before and after surgery. Three patients with persistently elevated PTH showed impaired renal function and they were excluded from this analysis. RESULTS: There were no difference in total calcium and ionized calcium (8.84±0.44 mg/dl vs. 8.74±0.32 mg/dl, 4.66±0.20 mg/dl vs. 4.56±0.31 mg/dl) between two groups. In comparison of variable group and normalized group, tumor size, 2.36 ±1.29 cm vs. 1.80±0.34 cm; preoperative PTH level, 418.18 ±488.90 pg/ml vs. 281.33±44.39 pg/ml; alkaline phosphatase levels, 369.36±570.80 IU/L vs. 202.17±115.63 IU/L; increment of bone densities of lumbar spine and femur, 18.32± 18.55% vs. 12.08±12.26%, 12.54±19.05% vs. 4.17± 5.03%; vitamin D level, 24.68±12.98 ng/ml vs. 31.22± 13.88 ng/ml; osteocalcin level is 15.71±5.33 ng/ml vs. 37.03±15.00 ng/ml. In 3 patients with creatinine level 4.00 ±3.64 mg/dl showed impaired renal function and their PTH level was persistently elevated. CONCLUSION: Patients with more advanced pHPT showed more variable postoperative PTH level than patients with normalized PTH level, although statistically insignificant due to small numbers. Patients with persistently elevated PTH level would be considered possibility of impaired renal function.

Extent of Prophylactic Neck Dissection in Sporadic Medullary Thyroid Cancer / 대한내분비외과학회지

PURPOSE: The extent of prophylactic lateral neck lymph node dissection is very controversial in medullary thyroid cancer. This retrospective study was undertaken to evaluate the efficacy of prophylactic lateral neck lymph node dissection. METHODS: A total of 29 patients underwent curative operation for medullary thyroid carcinoma at our institution. Of these 29 patients, 13 patients had prophylactic lateral neck dissection and 16 patients had non-prophylactic lateral neck dissection. Among 13 patients, one-compartment prophylactic lymph node dissection was performed in 10 patients and two-compartment prophylactic lymph node dissection was performed in 3 patients. Postoperative calcitonin level was evaluated between these groups. RESULTS: A normalized calcitonin level was detected after surgery in 74% of patients without lateral neck lymph node metastases, and in 10% of patients with lateral neck lymph node metastases. In comparison of prophylactic node dissection group and non-prophylactic node dissection group, the rate of normalized calcitonin level after surgery is 100%, 66.7% in stage 1, 100%, 50% in stage 2, 0%, 80% in stage 3, 14.3%, 0% in stage 4. In the patients who one-compartment prophylactic lymph node dissection was performed, 40% of patients had positive lymph node metastasis, and 70% had persistent hypercalcitoninemia. However, there was no postoperative hypercalcitoninemia in the patients with twocompartment prophylactic lymph node dissection although lymph node metastasis was not identified with pathologic examination. CONCLUSION: Prophylactic lymph node dissection was more effective in the early stage of medullary thyroid carcinoma than late stage. The two or more compartment lymph node dissection is more effective than just one-compartment dissection for the normalization of serum calcitonin level.

Serum Thyroglobulin Levels Predicting Recurrence and Distant Metastasis after Surgery in Patients with Differentiated Thyroid Cancer / 대한내분비학회지

BACKGROUND: Reports on serum thyroglobulin(Tg) levels being used to predict recurrence or distant metastasis during the follow-up of patients with differentiated thyroid cancer(DTC) has been inconsistent. In addition, there have been few reports that attempt to define the cut-off value of Tg for recurrence or distant metastasis obtained by a receiver operating characteristic(ROC) curve. As well, there are differences in opinions on what the value should be on the first serum Tg level measured just before radioactive iodine(RAI) ablation(Tg-RAI), during thyroxine administration (Tg-on), and after thyroxine withdrawal(Tg-off) during the follow-up. Reports on the positive predictive values(PPVs) and negative predictive values(NPVs) of these Tg values are rare. METHODS: A total of 205 patients(42 males, 163 females) with DTC were studied. All patients had undergone total or near-total thyroidectomy. After surgery and RAI ablation, annual thyroxine withdrawal 131I-whole body scan(WBS) with Tg measurements was performed. The mean duration of follow-up was 5.0 (1.4~7.4) years. The most sensitive and specific Tg values(cut-off values) for tumor recurrence and/or distant metastasis were selected by using ROC curves. We also calculated the PPVs and NPVs for recurrence and/or distant metastasis using two-by-two tables. RESULTS: Cut-off values of Tg-RAI, Tg-on, and Tg-off for recurrence were 11.8, 1.4, and 3.3ng/mL, respectively. For these values, the sensitivities were 85.4, 82.2, and 93.3%, with the specificitiesat 89.2, 92.4, and 88.0%. PPVs were 71.9, 77.1, and 77.0% while NPVs were 95.0, 94,4, and 97.8%. The cut-off values for distant metastasis were 27.4, 2.5, and 7.9ng/mL, respectively. For these cut-off values, the sensitivities were 86.7, 87.5, and 92.3%, with the specificities being 86.2, 90.8, and 80.2%. PPVs were 34.2, 46.7, and 25.0% and NPVs were 98.7, 98.8, and 99.3%. CONCLUSION: All three serum Tg levels were sensitive and specific markers for recurrence and distant metastasis. Their PPVs were low in contrast to the high NPVs. In comparison with Tg-on, Tg-off showed higher sensitivity and NPV as well as lower specificity and PPV. Therefore, in the case of higher Tg-on during the follow-up period, efforts to find recurrence and distant metastasis,such as 131I-WBS, should be done. In addition, regular measurement of Tg-off or Tg after stimulation with recombinant human TSH is recommended as a screening test.