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Peritoneal seeding of hepatocellular carcinoma (HCC) is incurable and has poor prognosis. A 68-year-old man underwent surgical resection for a 3.5 cm single nodular HCC at the tip of segment 3 and transarterial chemoembolization for a 1.5 cm-sized recurrent HCC at the tip of segment 6. 3 months later, an increasing 1 cm pelvic nodule on the rectovesical pouch warranted radiotherapy. Although it stabilized, a new 2.7 cm-sized peritoneal nodule in the right upper quadrant (RUQ) omentum appeared 3.5 years after radiotherapy. Hence, omental mass and small bowel mesentery mass excision were performed. 3 years later, recurrent peritoneal metastases in the RUQ omentum and rectovesical pouch progressed. 33 cycles of atezolizumab and bevacizumab treatment elicited stable disease response. Finally, laparoscopic left pelvic peritonectomy was performed without tumor recurrence. Herein, we present a case of HCC with peritoneal seeding that was successfully treated with surgery after radiotherapy and systemic therapy, leading to complete remission.
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Background and Objectives@#We compared the efficacy and safety of human bone marrow-derived mesenchymal stem cells (hBMSC), delivered at different doses and via different injection routes in an animal model of chronic kidney disease. @*Methods@#and Results: A total of ninety 12-week-old rats underwent 5/6 nephrectomy and randomized among nine groups: sham, renal artery control (RA-C), tail vein control (TV-C), renal artery low dose (RA-LD) (0.5×10 6 cells), renal artery moderate dose (RA-MD) (1.0×10 6 cells), renal artery high dose (RA-HD) (2.0×10 6 cells), tail vein low dose (TV-LD) (0.5×10 6 cells), tail vein moderate dose (TV-MD) (1.0×10 6 cells), and tail vein high dose (TV-HD) (2.0×10 6 cells). Renal function and mortality of rats were evaluated after hBMSC injection. Serum blood urea nitrogen was significantly lower in the TV-HD group at 2 weeks (p＜0.01), 16 weeks (p＜0.05), and 24 weeks (p＜0.01) than in the TV-C group, as determined by one-way ANOVA. Serum creatinine was significantly lower in the TV-HD group at 24 weeks (p＜0.05). At 8 weeks, creatinine clearance was significantly higher in the TV-MD and TV-HD groups (p＜0.01, p＜0.05) than in the TV-C group. In the safety evaluation, we observed no significant difference among the groups. @*Conclusions@#Our findings confirm the efficacy and safety of high dose (2×10 6 cells) injection of hBMSC via the tail vein.
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The incidence of hepatocellular carcinoma (HCC) associated with nonalcoholic fatty liver disease (NAFLD) has been increasing worldwide, including Asia. Most patients with NAFLD-related HCC are at a much-advanced stage and older age at the time of diagnosis than those with virus-related HCC because they have not undergone HCC surveillance. This review provides an overview of the mechanism of hepatocarcinogenesis in NAFLD, preventive strategies for NAFLDrelated HCC, and strategies for the surveillance of patients with NAFLD.
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Background and Objectives@#Voice change after thyroidectomy is a common complication that affects a patient’s quality of life. In this study, we aimed to compare voice outcomes between minimally invasive open hemithyroidectomy (MIOT) and conventional hemithyroidectomy.Materials and Method We enrolled 215 patients who underwent hemithyroidectomy performed by an experienced surgeon at our institute between June 2017 and December 2021. All patients underwent voice evaluations, including subjective and objective assessments, preoperatively and 2 weeks and 2 months postoperatively. @*Results@#Sixty-one patients underwent MIOT (M group) and 154 patients underwent conventional hemithyroidectomy (C group). There were 50 female (82.0%) and 11 male (18.0%) in the M group, and 129 female (83.8%) and 25 male (16.2%) in the C group. In both groups, the thyroidectomy-related voice questionnaire score increased at 2 weeks and 2 months postoperatively. However, no statistically significant differences were observed between the two groups. Voice parameters were analyzed according to sex. There were some changes in the parameters in both groups. However, no statistically significant differences were observed between the two groups. @*Conclusion@#Our study showed no differences in the acoustic results between MIOT and conventional hemithyroidectomy.
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Background@#/Aim: Radiotherapy (RT) is an effective local treatment for hepatocellular carcinoma (HCC). However, whether additional RT is safe and effective in patients with advanced HCC receiving atezolizumab plus bevacizumab remains unclear. This retrospective cohort study aimed to evaluate the feasibility of additional RT in these patients. @*Methods@#Between March and October 2021, we retrospectively analyzed seven patients with advanced HCC who received RT during treatment with atezolizumab plus bevacizumab. The median prescribed RT dose was 35 Gy (range, 33–66). Freedom from local progression (FFLP), progression-free survival (PFS), and overall survival (OS) after RT were analyzed. @*Results@#The median follow-up duration after RT was 14.2 months (range, 10.0–18.6). Of the seven patients, disease progression was noted in six (85.7%), the sites of disease progression were local in two (28.6%), intrahepatic in four (57.1%), and extrahepatic in four (57.1%). The median time of FFLP was not reached, and PFS and OS times were 4.0 (95% confidence interval [CI], 3.6–4.5) and 14.8% (95% CI, 12.5–17.2) months, respectively. The 1-year FFLP, PFS, and OS rates were 60% (95% CI, 43.8–76.2), 0%, and 85.7% (95% CI, 75.9–95.5), respectively. Grade 3 or higher hematologic adverse events (AEs) were not observed, but grade 3 nonhematologic AEs unrelated to RT were observed in one patient. @*Conclusions@#The addition of RT may be feasible in patients with advanced HCC treated with atezolizumab plus bevacizumab. However, further studies are required to validate these findings.
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Background@#/Aim: Despite the increasing proportion of elderly patients with hepatocellular carcinoma (HCC) over time, treatment efficacy in this population is not well established. @*Methods@#Data collected from the Korean Primary Liver Cancer Registry, a representative cohort of patients newly diagnosed with HCC in Korea between 2008 and 2017, were analyzed. Overall survival (OS) according to tumor stage and treatment modality was compared between elderly and non-elderly patients with HCC. @*Results@#Among 15,186 study patients, 5,829 (38.4%) were elderly. A larger proportion of elderly patients did not receive any treatment for HCC than non-elderly patients (25.2% vs. 16.7%). However, OS was significantly better in elderly patients who received treatment compared to those who did not (median, 38.6 vs. 22.3 months; P0.05). After IPTW, in intermediate-stage HCC, surgery (median, 66.0 vs. 90.3 months) and transarterial therapy (median, 36.5 vs. 37.2 months), and in advanced-stage HCC, transarterial (median, 25.3 vs. 26.3 months) and systemic therapy (median, 25.3 vs. 26.3 months) yielded comparable OS between the elderly and non-elderly HCC patients (all P>0.05). @*Conclusions@#Personalized treatments tailored to individual patients can improve the prognosis of elderly patients with HCC to a level comparable to that of non-elderly patients.
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Background and Objectives@#We evaluated the effect of adipose-derived stem cell-derived conditioned medium (ADSC-CM) on the renal function of rats with renal ischemia-reperfusion injury (IRI)-induced acute kidney injury. @*Methods@#and Results: Forty male Sprague‐Dawley rats were randomly divided into four groups: sham, nephrectomy control, IRI control, ADSC-CM. The ADSC-CM was prepared using the three-dimensional spheroid culture system and injected into renal parenchyme. The renal function of the rats was evaluated 28 days before and 1, 2, 3, 4, 7, and 14 days after surgical procedures. The rats were sacrificed 14 days after surgical procedures, and kidney tissues were collected for histological examination. The renal parenchymal injection of ADSC-CM significantly reduced the serum blood urea nitrogen and creatinine levels compared with the IRI control group on days 1, 2, 3, and 4 after IRI. The renal parenchymal injection of ADSC-CM significantly increased the level of creatinine clearance compared with the IRI control group 1 day after IRI. Collagen content was significantly lower in the ADSC-CM group than in the IRI control group in the cortex and medulla. Apoptosis was significantly decreased, and proliferation was significantly increased in the ADSC-CM group compared to the IRI control group in the cortex and medulla. The expressions of anti-oxidative makers were higher in the ADSC-CM group than in the IRI control group in the cortex and medulla. @*Conclusions@#The renal function was effectively rescued through the renal parenchymal injection of ADSC-CM prepared using a three-dimensional spheroid culture system.
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Hepatocellular carcinoma (HCC) is highly prevalent and the third most common cause of cancer-related death in Asia. In contrast to the West, the main etiology of HCC in many Asian countries except Japan is chronic hepatitis B virus infection. Differences in the major causes of HCC lead to significant clinical and treatment differences. This review summarizes and compares guidelines on managing HCC from China, Hong Kong, Taiwan, Japan, and South Korea. From oncology and socio-economic perspectives, factors such as underlying diseases, staging methods, government policies, insurance coverage, and medical resources contribute to varying treatment strategies among countries. Furthermore, the differences in each guideline are fundamentally caused by the lack of incontrovertible medical evidence, and even existing results of clinical trials can be interpreted differently. This review will provide a complete overview of the current Asian guidelines for HCC in recommendations and in practice.
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Parathyroid carcinoma (PC) in cases of secondary or tertiary hyperparathyroidism is relatively uncommon, and only a few case reports have described this entity. Although some papers have reported patients with one or two parathyroid malignancies, multiple PC–especially three or more–have been even more rarely reported. Herein, we report a case of secondary hyperparathyroidism due to multiple PCs in a chronic hemodialysis patient. A 54-year-old man with end-stage kidney disease was referred for hyperparathyroidism. He had been diagnosed with chronic kidney disease in 2001 and had begun hemodialysis in 2009. In laboratory tests, intact parathyroid hormone (iPTH) was markedly elevated to 1,144.1 pg/mL (normal range: 15.0–68.3 pg/mL) and serum calcium was mildly elevated to 10.56 mg/dL (normal range: 8.5–10.3 mg/dL). Ultrasonography showed hypoechoic nodules in the posterior part of both thyroid glands. All three nodules showed increased uptake on a 99mTc sestamibi scan. The patient underwent total parathyroidectomy with autotransplantation to the right forearm. Histopathology findings showed three PCs with capsular invasion and one parathyroid hyperplasia. In the immediate postoperative period, the iPTH level dropped from 1,446.8 to 82.4 pg/dL and, after 1 month, to 4.0 pg/dL. This patient needed oral calcium carbonate and active vitamin D to maintain appropriate serum calcium levels. Although multiple PCs are rare, they can cause secondary hyperparathyroidism. Therefore, clinicians should suspect multiple PCs when patients’ serum iPTH levels are exceptionally high. Additionally, since PCs could occur in multiple glands, autotransplantation of the parathyroid gland after parathyroidectomy should be done carefully.
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Background/Aims@#Primary liver cancer is one of the leading causes of cancer mortality worldwide. However, the causes of death have not been studied in detail in patients with liver cancer. @*Methods@#The causes of death and cause-specific mortality risks in patients with primary liver cancer, diagnosed during 2000–2016, were investigated using the nationwide population-based cancer registry data in South Korea (n=231,388). The cumulative incidence function and Fine-Gray models were used to estimate the cause-specific mortality under the competing risks. Risks of non-cancer deaths relative to the general population were compared by standardized mortality ratios (SMRs). @*Results@#Among 179,921 total deaths, 92.4%, 1.7%, and 6.0% of patients died of primary liver cancer, cancer from other sites, and non-cancer illnesses, respectively. Proportionate mortality from liver cancer remained high. The 5-year competing risks probability of death from liver cancer varied by tumor stage, from 42% to 94%, and it remained high 10 years after the diagnosis (61–95%). Competing mortality from other causes has continuously increased. The most common non-cancer causes of death were underlying liver diseases (SMR, 15.6; 95% confidence interval [CI], 15.1–16.1) and viral hepatitis (SMR, 46.5; 95% CI, 43.9–49.2), which demonstrated higher mortality risks compared to the Korean general population. Higher mortality risks of suicide (SMR, 2.6; 95% CI, 2.4–2.8) was also noted. @*Conclusions@#Patients with liver cancer are most likely to die from liver cancer and related liver disease, even 10 years after the diagnosis, highlighting a need for specialized long-term follow-up care.
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The prognosis of patients with advanced hepatocellular carcinoma (HCC) with tumor thrombus extending to the inferior vena cava (IVC) is extremely poor. Herein, we present a rare case of advanced HCC that was treated with sorafenib and radiotherapy, leading to complete remission. This patient had a 9 cm infiltrative HCC occupying almost the entire left lobe with a tumor thrombus extending through the hepatic vein, IVC, and left portal vein. The patient received 400 mg sorafenib twice daily. One year after the start of sorafenib, intensity-modulated radiation therapy for viable HCC and tumor thrombus was performed with a dose of 5,500 cGy. Twenty-seven months after the starting date of sorafenib, there was no intratumoral arterial enhancement, which suggested a complete response according to the modified RECIST criteria. This case suggests that the combination of sorafenib and radiotherapy might provide clinical benefits in patients with advanced HCC with IVC tumor thrombus.
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Background and Objectives@#Papillary thyroid carcinoma (PTC) with lateral neck lymph node metastasis is known as a major risk factor for tumor recurrence after surgical treatment. The aim of this study is to identify risk factors for loco-regional recurrence in patients with PTC with lateral neck lymph node metastasis, which has a high risk of recurrence.Subjects and Method This study involved 319 patients who underwent total thyroidectomy, central lymph node (LN) and lateral LN dissection due to PTC. The patients’ demographics and pathological factors, including lymph node metastasis were retrospectively reviewed. Univariate, multivariate and C-index with variable selection analyses were performed to identify factors associated with recurrence-free survival (RFS). @*Results@#A mean follow-up of 101 months, 35 (10.9%) patients had a loco-regional recurrence. In multivariate analysis according to loco-regional recurrence, patients with a primary tumor of more than 4 cm, multifocality, vascular invasion, and bilateral lateral cervical metastasis were associated with worse RFS. In the variable selection analysis, lateral lymph node metastasis ratio was also statistically significant. @*Conclusion@#PTC with lateral neck lymph node metastasis included tumors larger than 4 cm. Multifocality, vascular invasion, high lateral lymph node metastasis ratio and bilateral neck lymph node metastasis are predictive factors of loco-regional recurrence, and these risk factors should be carefully followed-up after surgery.
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Background@#Hürthle cell carcinoma (HCC), a type of thyroid carcinoma, is rare in South Korea, and few studies have investigated its prognosis. @*Methods@#This long-term multicenter retrospective cohort study evaluated the clinicopathological features and clinical outcomes in patients with HCC who underwent thyroid surgery between 1996 and 2009. @*Results@#The mean age of the 97 patients included in the study was 50.3 years, and 26.8% were male. The mean size of the primary tumor was 3.2±1.8 cm, and three (3.1%) patients had distant metastasis at initial diagnosis. Ultrasonographic findings were available for 73 patients; the number of nodules with low-, intermediate-, and high suspicion was 28 (38.4%), 27 (37.0%), and 18 (24.7%), respectively, based on the Korean-Thyroid Imaging Reporting and Data System. Preoperatively, follicular neoplasm (FN) or suspicion for FN accounted for 65.2% of the cases according to the Bethesda category, and 13% had malignancy or suspicious for malignancy. During a median follow-up of 8.5 years, eight (8.2%) patients had persistent/recurrent disease, and none died of HCC. Older age, gross extrathyroidal extension (ETE), and widely invasive types of tumors were significantly associated with distant metastasis (all P<0.01). Gross ETE (hazard ratio [HR], 27.7; 95% confidence interval [CI], 2.2 to 346.4; P=0.01) and widely invasive classification (HR, 6.5; 95% CI, 1.1 to 39.4; P=0.04) were independent risk factors for poor disease-free survival (DFS). @*Conclusion@#The long-term prognosis of HCC is relatively favorable in South Korea from this study, although this is not a nation-wide data, and gross ETE and widely invasive cancer are significant prognostic factors for DFS. The diagnosis of HCC by ultrasonography and cytopathology remains challenging.
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Background@#Early identification of patients with high-risk papillary thyroid microcarcinoma (PTMC) that is likely to progress has become a critical challenge. We aimed to identify somatic mutations associated with lateral neck lymph node (LN) metastasis (N1b) in patients with PTMC. @*Methods@#Whole-exome sequencing (WES) of 14 PTMCs with no LN metastasis (N0) and 13 N1b PTMCs was performed using primary tumors and matched normal thyroid tissues. @*Results@#The mutational burden was comparable in N0 and N1b tumors, as the median number of mutations was 23 (range, 12 to 46) in N0 and 24 (range, 12 to 50) in N1b PTMC (P=0.918). The most frequent mutations were detected in PGS1, SLC4A8, DAAM2, and HELZ in N1b PTMCs alone, and the K158Q mutation in PGS1 (four patients, Fisher’s exact test P=0.041) was significantly enriched in N1b PTMCs. Based on pathway analysis, somatic mutations belonging to the receptor tyrosine kinase-RAS and NOTCH pathways were most frequently affected in N1b PTMCs. We identified four mutations that are predicted to be pathogenic in four genes based on Clinvar and Combined Annotation-Dependent Depletion score: BRAF, USH2A, CFTR, and PHIP. A missense mutation in CFTR and a nonsense mutation in PHIP were detected in N1b PTMCs only, although in one case each. BRAF mutation was detected in both N0 and N1b PTMCs. @*Conclusion@#This first comprehensive WES analysis of the mutational landscape of N0 and N1b PTMCs identified pathogenic genes that affect biological functions associated with the aggressive phenotype of PTMC.
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Background@#The association between Graves’ disease (GD) and co-existing thyroid cancer is still controversial and most of the previously reported data have been based on surgically treated GD patients. This study investigated the clinicopathological findings and prognosis of concomitant thyroid cancer in GD patients in the era of widespread application of ultrasonography. @*Methods@#Data of GD patients who underwent thyroidectomy for thyroid cancer between 2010 and 2019 in three tertiary hospitals in South Korea (Asan Medical Center, Chonnam National University Hwasun Hospital, and Pusan National University Hospital) were collected and analyzed retrospectively. In the subgroup analysis, aggressiveness and clinical outcomes of thyroid cancer were compared nodular GD and non-nodular GD groups according to the presence or absence of the thyroid nodules other than thyroid cancer (index nodules). @*Results@#Of the 15,159 GD patients treated at the hospitals during the study period, 262 (1.7%) underwent thyroidectomy for coexisting thyroid cancer. Eleven patients (4.2%) were diagnosed with occult thyroid cancer and 182 patients (69.5%) had microcarcinomas. No differences in thyroid cancer aggressiveness, ultrasonographic findings, or prognosis were observed between the nodular GD and non-nodular GD groups except the cancer subtype. In the multivariate analysis, only lymph node (LN) metastasis was an independent prognostic factor for recurrent/persistent disease of thyroid cancer arising in GD (P=0.020). @*Conclusion@#The prevalence of concomitant thyroid cancer in GD patients was considerably lower than in previous reports. The clinical outcomes of thyroid cancer in GD patients were also excellent but, more cautious follow-up is necessary for patients with LN metastasis in the same way as for thyroid cancer in non-GD patients.
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Several molecular-targeted agents have been tested as first- or second-line therapies for hepatocellular carcinoma (HCC) but failed to improve clinical outcomes; sorafenib has been the only approved systemic agent for treating HCC for almost 10 years. Regorafenib resulted in a significant improvement in overall survival and thus was approved for HCC patients previously treated with sorafenib. Subsequently, cabozantinib and ramucirumab demonstrated superior overall survival compared with placebos in phase III clinical trials. Immune checkpoint inhibitors such as nivolumab with or without ipilimumab and pembrolizumab are also available in some countries for patients who are unresponsive to sorafenib. Some second-line agents are available for patients who are unresponsive to sorafenib; however, little is known about the considerations for selecting appropriate secondline systemic agents. Hence, this study aimed to review the current and future perspectives of second-line systemic agents.
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Purpose@#We evaluated the diagnostic performance of LI-RADS version 2018 using gadoxetic acid enhanced MRI for recurrent but untreated HCC in patients with prior history of HCC. @*Materials and Methods@#We enrolled 50 consecutive patients who 1) prior history of treatment of HCC, 2) underwent liver surgery for radiological/clinical diagnosis of new HCC between 2013 to 2018, 3) had gadoxetic acid enhanced MRI within one month before surgery, and 4) did not have more than five HCCs or infiltrative tumors only. Two radiologists reviewed MRI and determined the presence of LR3, LR4 and LR5 observations except previously treated tumors based on LI-RADS version 2018 in consensus. We sub-classified LR4 into LR4m (LR4 with major features only) and LR4u (LR4 upgraded from LR3 by ancillary features). LR4u were further sub-classified into LR4ua (with arterial phase hyperenhancement) and LR4un (without arterial phase hyperenhancement). @*Results@#PPV for LR5, LR4 and LR3 observations for recurrent HCC were 100%, 61.5% and 25.0%, respectively. 100% (3/3) of LR4m were HCC. However, PPV of LR4u was 56.5%. PPV of LR4ua and LR4un were 73.3% and 25.0%, respectively. Sensitivity of LR5 and LR5+LR4 observations as a diagnostic threshold were 32.1% and 89.3%, respectively. Sensitivity for LR5+LR4m+LR4ua observations for diagnosis of HCC were 83.7% and significantly superior to that of LR5 without significant deterioration of specificity (75.0%). @*Conclusion@#In patients with prior history of HCC, LR4 observations by major features or with APHE may be regarded as recurrent HCCs given high sensitivity and comparable specificity/PPV to LR5 observations.
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Branchial cleft cysts are the most common lateral neck mass, and usually have well-delineated cystic structures under ultrasonography. Ultrasonography and fine needle aspiration cytology is very helpful during preoperative diagnosis. However, these cysts may occur in unusual locations and have a sonographic morphology similar to malignant thyroid neoplasm. A 61-year-old woman presented with thyroid nodules, and ultrasonography revealed a 0.8-cm, hypoechoic, solid nodule with microcalcifications in the right lobe of thyroid in the lower portion.Postoperative histopathological examination revealed the 0.8-cm hypoechoic nodule to be a branchial cleft cyst. In addition, concurrent medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) were found. Herein, we present a rare case of branchial cleft cyst mimicking malignant thyroid neoplasm concurrent with medullary and PTC.
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Background@#Postoperative thyroid stimulating hormone (TSH) suppression therapy is recommended for patients with intermediate- and high-risk differentiated thyroid cancer to prevent the recurrence of thyroid cancer. With the recent increase in small thyroid cancer cases, the extent of resection during surgery has generally decreased. Therefore, questions have been raised about the efficacy and long-term side effects of TSH suppression therapy in patients who have undergone a lobectomy. @*Methods@#This is a multicenter, prospective, randomized, controlled clinical trial in which 2,986 patients with papillary thyroid cancer are randomized into a high-TSH group (intervention) and a low-TSH group (control) after having undergone a lobectomy. The principle of treatment includes a TSH-lowering regimen aimed at TSH levels between 0.3 and 1.99 μIU/mL in the low-TSH group. The high-TSH group targets TSH levels between 2.0 and 7.99 μIU/mL. The dose of levothyroxine will be adjusted at each visit to maintain the target TSH level. The primary outcome is recurrence-free survival, as assessed by neck ultrasound every 6 to 12 months. Secondary endpoints include disease-free survival, overall survival, success rate in reaching the TSH target range, the proportion of patients with major cardiovascular diseases or bone metabolic disease, the quality of life, and medical costs. The follow-up period is 5 years. @*Conclusion@#The results of this trial will contribute to establishing the optimal indication for TSH suppression therapy in low-risk papillary thyroid cancer patients by evaluating the benefit and harm of lowering TSH levels in terms of recurrence, metabolic complications, costs, and quality of life.
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Background@#We aimed to evaluate the clinicopathological features and biological behaviors of Korean thyroid cancer patients with rare variants of papillary thyroid carcinoma (PTC) to address the ambiguity regarding the prognostic consequences of these variants. @*Methods@#We retrospectively reviewed the medical records of 5,496 patients who underwent thyroid surgery for PTC, between January and December 2012, in nine tertiary hospitals. Rare PTC variants included tall cell (TCV), columnar cell (CCV), diffuse sclerosing (DSV), cribriform-morular (CMV), solid (SV), hobnail, and Warthin-like variants. Recurrence-free survival (RFS) was defined as the time from the date of thyroidectomy until recurrence. @*Results@#Rare variants accounted for 1.1% (n=63) of the PTC patients; with 0.9% TCV, 0.02% CCV, 0.1% DSV, 0.1% CMV, and 0.1% SV. The mean age of patients and primary tumor size were 42.1±13.1 years and 1.3±0.9 cm, respectively. Extrathyroidal extension and cervical lymph node metastasis were observed in 38 (60.3%) and 37 (58.7%) patients, respectively. Ultrasonographic findings revealed typical malignant features in most cases. During a median follow-up of 7 years, 6.3% of patients experienced a locoregional recurrence. The 5-year RFS rates were 71.4% in patients with DSV or SV, 95.9% for TCV, or CCV, and 100% for other variants. DSV emerged an independent risk factor associated with shorter RFS. @*Conclusion@#In this multicenter Korean cohort, rare variants accounted for 1.1% of all PTC cases, with TCV being the most frequent subtype. DSV emerged as a significant prognostic factor for RFS.