Migration of Risk Classification Between the JAES Versus ATA guidelines for Papillary Thyroid Carcinoma.

BACKGROUND: This study aimed to investigate outcomes in the same cohort of patients with papillary thyroid carcinoma (PTC) risk-stratified according to the Japan Association of Endocrine Surgery (JAES) and American Thyroid Association (ATA) guidelines. METHODS: A total of 1044 patients with PTC who underwent initial thyroidectomy at Yokohama City University Medical Center between January 2000 and June 2022 were included. RESULTS: According to the JAES guidelines, 480 (46%), 386 (37%), and 178 (17%) patients were classified as low, intermediate, or high risk, respectively. Furthermore, according to the ATA guidelines, 590 (57%), 261 (25%), and 193 (18%) patients were reclassified as low, intermediate, or high risk, respectively. Among 1044 patients with PTC, the 10-year cause-specific survival (CSS) rates of patients with JAES low and intermediate risk were 99.7 and 98.6%, respectively, and there was no statistically difference (p = 0.096). However, the 10-year CSS rates of patients with ATA low and intermediate risk were 100 and 99.5%, respectively (p = 0.007). Among 1001 patients with M0 PTC, the 10-year distant metastasis-free survival (DMFS) rates of patients with JAES intermediate and high risk were 94.2, and 76.7%, respectively (p < 0.001). However, the 10-year DMFS rates of patients with ATA intermediate and high risk were 88.1 and 86.6%, respectively (p = 0.233), and there was no statistically difference. CONCLUSIONS: Both JAES and ATA risk classifications properly stratified the PTC patients. Furthermore, the ATA risk classification more precisely extracted patients with better and worse prognoses.

New Insights on the Importance of the Extent of Vascular Invasion in Widely Invasive Follicular Thyroid Carcinoma.

BACKGROUND: This study aimed to investigate the association between the extent of vascular invasion (VI) and the outcome of widely invasive follicular thyroid carcinoma (WI-FTC). METHODS: The records of 107 patients with WI-FTC confirmed by surgical specimens from January 2005 to December 2016 were retrospectively reviewed. RESULTS: Among the 107 patients with WI-FTC, those with a VI of < 4 (n = 62) and ≥ 4 (n = 45) had a 10 year cause-specific survival (CSS) rate of 97.7% and 89.4% (p = 0.008), respectively. Univariate analysis identified M1 (p = 0.001), and the number of VI of ≥ 4 as significant negative prognostic factors for CSS. Multivariate analysis identified M1 (hazard ratio [HR] = 9.366) as independent negative prognostic factor for CSS. Among the 72 patients with M0 WI-FTC, those with a VI of < 2 (n = 33) and ≥ 2 (n = 39) had a 10-year distant metastasis-free survival (DMFS) rate of 96.8% and 56.8% (p = 0.001), respectively. Univariate analysis identified age ≥ 55 years (p = 0.011), presence of VI, the number of VI of ≥ 2, and resection margin status (p < 0.001) as significant negative prognostic factors for DMFS. Multivariate analysis identified the number of VI ≥ 2 (HR = 9.137), and resection margin status (HR = 5.853) as independent negative prognostic factors for DMFS. CONCLUSIONS: It may be unnecessary that WI-FTC with curative resection margin status and a VI of < 2, especially in capsular invasion only, routinely undergo completion thyroidectomy and postoperative ablation.

Encapsulated Angioinvasive Follicular Thyroid Carcinoma: Prognostic Impact of the Extent of Vascular Invasion.

BACKGROUND: Previous studies have reported an association between four or more foci of vascular invasion (VI) and thyroid cancer prognosis, while the current study aimed to investigate the association between extent of VI and outcome of encapsulated angioinvasive follicular thyroid carcinoma (FTC). METHODS: The records of 303 patients with encapsulated angioinvasive FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were retrospectively reviewed. Thirteen patients had distant metastasis at diagnosis and were classified as M1. RESULTS: Among the 290 patients with M0 encapsulated angioinvasive FTC, the 10-year disease-free survival (DFS) rate was 85.6%. Those with a VI of 1 (n = 131) or ≥ 2 (n = 159) had a 10-year DFS rate of 94.9% and 77.9% (p < 0.001), respectively, and those with a VI of 1-3 (n = 211) or ≥ 4 (n = 79) had a 10-year DFS rate of 86.3% and 83.3% (p = 0.311), respectively. Multivariate analysis identified age ≥ 55 years (p = 0.031) and VI ≥ 2 (p = 0.002) as independent negative prognostic factors for DFS. Patients with M0 encapsulated angioinvasive FTC aged ≥ 55 years and VI ≥ 2 had significantly poorer prognosis and a 10-year DFS rate of 66.4% (p < 0.001). CONCLUSIONS: Patients with encapsulated angioinvasive FTC who had two or more foci of VI, especially patients aged ≥ 55 years, should be carefully followed-up.

Impact of Local Control on Clinical Course in Stage IVC Anaplastic Thyroid Carcinoma.

BACKGROUND: The present study investigated the association between local resection and cause of death in anaplastic thyroid carcinoma (ATC) patients with stage IVC disease. METHODS: A total of 54 ATC patients with stage IVC disease were included in the study. Information including patient characteristics, laboratory data including complete blood count, treatment, and death were collected for analysis. RESULTS: The median overall survival (OS) for patients with or without resection was 8.4 [95% confidence interval (CI) 5.9-14.4)] and 4.2 (95% CI 2.5-6.2) months, respectively (p < 0.001). No patients survived without resection at 1 year. Univariate analysis revealed that resection (p < 0.001) and radiotherapy (p = 0.018) were significantly associated with OS. Multivariate analysis revealed that resection (hazard ratio 0.257; 95% CI 0.115-0.575; p < 0.001) was the only independent prognostic factor of OS. In ATC patients with known resection status, the median OS for the patients with a resection status of R0/1 (n = 28) and R2 (n = 7) were 13.0 (95% CI 7.5-18.7) and 1.7 (95% CI 0.1-6.2) months, respectively (p < 0.001). The most common specific cause of death was respiratory insufficiency (35%), followed by airway obstruction (25%) and cerebral cardiovascular-related death (5%). The frequency of airway obstruction was significantly lower in patients with resection (p = 0.018). CONCLUSIONS: Resection probably impacts on clinical course in ATC patients despite the presence of distant metastasis. However, R2 resection is likely to be harmful and surgeons should carefully consider the resectability of thyroid tumors.

Outcomes for Minimally Invasive Follicular Thyroid Carcinoma in Relation to the Change in Age Stratification in the AJCC 8th Edition.

BACKGROUND: Completion total thyroidectomy with radioactive iodine (RAI) therapy is not uniformly recommended for minimally invasive follicular thyroid carcinomas (MI-FTCs) without distant metastasis, but may be considered for cases with a risk factor of recurrence, such as age ≥ 45 years. OBJECTIVE: The present study aimed to investigate the outcomes for patients with MI-FTC using a stratification age of 55 years. METHODS: The records of 478 patients with MI-FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were retrospectively reviewed. Twenty patients had distant metastasis at diagnosis and were subsequently classified as M1. RESULTS: Among the 478 patients with MI-FTC, univariate analysis identified that age ≥ 55 years (p = 0.002) and M1 (p < 0.001) were related to cause-specific survival. In 458 patients with M0 MI-FTC, male sex (p = 0.041), age ≥ 55 years (p = 0.001), and tumor size > 40 mm (p < 0.001) were related to poor disease-free survival (DFS) in univariate analysis. Multivariate analysis showed that age ≥ 55 years (p = 0.005) and tumor size > 40 mm (p = 0.005) were independent prognostic factors for DFS. The 10-year DFS rates of patients aged < 45 years, 45 years ≤ age < 55 years, and ≥ 55 years were 97.0%, 95.5%, and 86.4%, respectively. CONCLUSIONS: The change in the recommended age for completion total thyroidectomy with RAI, from 45 to 55 years, seemed reasonable.

Impact of lenvatinib on renal function: long-term analysis of differentiated thyroid cancer patients.

BACKGROUND: Because lenvatinib is well known to induce proteinuria by blocking the vascular endothelial growth factor (VEGF) pathway, renal function is a concern with long-term administration of lenvatinib. The long-term effects of lenvatinib on renal function in patients with advanced differentiated thyroid carcinoma (DTC) were analyzed. METHOD: This study involved 40 DTC patients who continued lenvatinib therapy for ≥6 months. Estimated glomerular filtration rate (eGFR) was calculated as an indicator of renal function. The temporal course of eGFR, effects of baseline eGFR on eGFR changes, and factors affecting renal impairment were investigated. RESULTS: The overall cohort showed sustainable decreases in eGFR, with decreased values of 11.4, 18.3, and 21.0 mL/min/1.73 m2 at 24, 36, and 48 months after starting treatment, respectively. No differences in eGFR decrease every 6 months were seen for three groups classified by baseline eGFR ≥90 mL/min/1.73 m2 (n = 6), < 90 but ≥60 mL/min/1.73 m2 (n = 26), or < 60 but ≥45 mL/min/1.73 m2 (n = 8). Grade 3 proteinuria was associated with declines in eGFR (p = 0.0283). Long observation period was also associated with decreases in eGFR (p = 0.0115), indicating that eGFR may decrease in a time-dependent manner. CONCLUSION: Lenvatinib can induce declines in eGFR, particularly with treatment duration > 2 years, regardless of baseline eGFR. Proteinuria is a risk factor for declines in eGFR. Patients who start lenvatinib with better renal function show a renal reserve capacity, prolonging clinical outcomes. Decision-making protocols must balance the benefits of lenvatinib continuation with acceptable risks of harm.

Expression of fibroblast growth factor receptor 4 and clinical response to lenvatinib in patients with anaplastic thyroid carcinoma: a pilot study.

PURPOSE: Fibroblast growth factor receptor 4 (FGFR4) expression has association with tumor malignancy. In thyroid cancers, FGFR4 has been reported to be characteristically expressed in aggressive thyroid tumors, such as anaplastic thyroid carcinoma (ATC). METHODS: We investigated FGFR4 expression in patients with ATC and analyzed their clinical responses to lenvatinib. Primary tumor samples were obtained from 12 patients with ATC who underwent surgery or core needle biopsy. FGFR4 protein expression in all ATC samples was analyzed via immunohistochemistry, and the treatment efficacy of lenvatinib was evaluated. RESULTS: The proportion of FGFR4-positive cells in the samples ranged from 0 to 50%. Four patients had partial responses, and three patients had stable diseases as a best clinical response to lenvatinib. The median PFS durations of patients with none, weak, and moderate intensity were 0.5, 3.2 (95% CI 1.1-not estimable [NE]), and 4.6 (95% CI 1.1-NE) months, respectively (p = 0.003). CONCLUSIONS: Because FGFR4 was expressed in ATC tissues, the FGFR4 expression might be associated with the treatment efficacy of lenvatinib in a part of ATC patients. To clarify whether FGFR4 can serve as a prognostic or predictive factor for lenvatinib therapy, more cases must be accumulated.

Clinical outcomes and risk stratification for papillary thyroid carcinoma presenting with distant metastasis before the era of tyrosine kinase inhibitors.

Radioactive iodine (RAI) therapy has been the mainstay of treatment for papillary thyroid carcinoma (PTC) patients with distant metastasis (DM). Although tyrosine kinase inhibitors (TKIs) were introduced for the treatment of RAI refractory metastatic thyroid carcinoma several years ago, clinical outcomes for PTC patients with DM treated using RAI therapy remain unclear. We retrospectively examined 64 PTC patients (9 men, 55 women) with DM at diagnosis treated using RAI therapy without administration of any kind of chemotherapy or TKIs. Median age of patients was 58 years. Site of DM was the lungs (n = 59), bone (n = 3), and pleural dissemination (n = 2). No patients showed multiple-organ metastases at diagnosis. By the end of the study period, 21 patients had died of PTC. Cause-specific survival rates at 10, 15, and 20 years after initial surgery were 68.2%, 63.6% and 61.1%, respectively. Uni- and multivariate analyses identified age ≥55 years (HR 3.1, p = 0.023), site of DM other than the lungs (HR 13.4, p < 0.0001), and DM with no RAI avidity (HR 5.1, p = 0.0098) as factors independently associated with disease-related death. When analyses were restricted to patients with lung metastasis (n = 59), surgical non-curability was another independent risk factor (HR 5.2, p = 0.0047) in addition to age and RAI avidity. According to risk stratification analysis based on these risk factors, patients with site of DM other than the lungs or with lung metastasis showing ≥2 risk factors among age ≥55 years, DM with no RAI avidity, and surgical non-curability are expected to show higher mortality rates.

[Efficacy and Safety of Lenvatinib for Unresectable Anaplastic Thyroid Cancer].

The 208 trial showed that lenvatinib has a significant antitumor effect on unresectable anaplastic thyroid cancer(ATC). Herein, we present a retrospective review of data from 7 patients with unresectable ATC who received lenvatinib in our hospital between May 2015 and October 2016. Two patients were men and 5 were women. The median age was 78(range, 72-85)years, and 1 patient had Stage IV A disease, 1 had Stage IV B, and 5 had Stage IV C at diagnosis, respectively. Three patients experienced a partial response and 1 patient experienced stable disease. The response rate was 43%, and the disease control rate was 57%. The median progression-free survival(PFS)was 4.1(range, 1.1-12.2)months. Grade 3 and Grade 4 gastrointestinal hemorrhage were observed in 2patients and Grade 3 anorexia was observed in 1 patient. Further clinical research seems to be needed to establish a treatment strategy involving lenvatinib for ATC.

Larotrectinib efficacy for liver metastases in papillary thyroid carcinoma patient harboring SQSTM1-NTRK1 fusion.

BACKGROUND: Pooled data analysis from three phase I/II larotrectinib clinical trials revealed that larotrectinib demonstrated rapid and durable disease control and a favorable safety profile for patients with neurotrophic-tropomyosin receptor kinase (NTRK) fusion positive thyroid carcinoma. Herein, we report the case of a patient with papillary thyroid carcinoma (PTC) and liver metastases who demonstrated a durable response to treatment with larotrectinib. CASE PRESENTATION: A 50-year-old female with PTC was referred to our hospital for postoperative observation. Computed tomography (CT) scan was performed to screen for distant metastasis, since thyroglobulin concentration increased gradually, and revealed multiple distant metastases, including multiple liver metastases. Radioactive iodine was administered at a dose of 100 mCi. However, uptake was observed only in the thyroid bed, and distant metastases had no avidity. As liver metastases progressed, lenvatinib (24 mg/day) was initiated after confirmation of liver metastases by liver biopsy 9 years and 1 month after the initial referral to our hospital. Since the multiple metastases became refractory for lenvatinib, the OncoGuide™ NCC Oncopanel System was performed, and the SQSTM1-NTRK1 gene fusion was confirmed. Larotrectinib was subsequently administered at a dose of 200 mg/day. The CT before the initiation of larotrectinib showed multiple liver metastases with a maximum diameter of 48 mm. The first CT evaluation at 1 month after the initiation of larotrectinib treatment showed that the tumor volume was reduced by 28% in the RECIST 1.1 criteria. After 3 months of larotrectinib treatment, a 38% reduction in the tumor volume was achieved as the best clinical response. The only side effect was grade 1 myalgia. At 12 months after the initiation of larotrectinib treatment, none of the lesions had progressed. CONCLUSIONS: In conclusion, larotrectinib demonstrated effective antitumor activity against liver metastases of PTC, a relatively rare site of distant metastasis. Furthermore, the efficacy of larotrectinib was maintained, even though the patient had a history of multi-tyrosine kinase inhibitor treatment and a relatively infrequent fusion gene, SQSTM1-NTRK1.

Prognostic significance of metastatic lymph node size and extra-nodal extension in papillary thyroid carcinoma according to the 9th edition of general rules for the description of thyroid cancer risk stratification: a single center validation study.

PURPOSE: In the 9th edition of general rules for the description of thyroid cancer (GRDTC), the N factor was subdivided according to the maximum diameter of metastatic lymph nodes, presence of extra-nodal extension (ENE), and location of mediastinal lymph nodes. This study aimed to investigate the clinical usefulness of the 9th GRDTC risk stratification in papillary thyroid carcinoma (PTC) patients with lymph node metastasis. METHODS: A total of 703 PTC patients with lymph node metastasis who underwent initial thyroidectomy at our institution between January 2000 and October 2023 were included. RESULTS: Among the 703 patients with PTC, the 10-year cause specific survival rates of patients with pN1a-1 (n = 383), pN1a-2 (n = 13), pN1b-1 (n = 234), and pN1b-2 (n = 73) were 97.9%, 100%, 95.4%, and 76.2%, respectively (p < 0.001). Therefore, the pN1b-2 classification identified patients with a worse prognosis among those with pN1b. Among the 664 patients with M0 PTC, the 10-year disease free survival (DFS) rates of the patients with pN1a-1 (n = 378), pN1a-2 (n = 13), pN1b-1 (n = 215), and pN1b-2 (n = 58) were 86.9%, 62.5%, 79.9%, and 59.4%, respectively (p < 0.001). The pN1b-2 category was associated with worse DFS in pN1b patients. CONCLUSIONS: The 9th edition of the GRDTC may be useful for stratifying the prognosis of patients with PTC. The risk assessment of PTC-related death and recurrence will be more accurate by considering the size of lymph node metastasis and ENE in GRDTC.

Genetic landscape of 482 thyroid carcinomas: analysis with the national datacenter for cancer genomic medicine in Japan.

PURPOSE: Comprehensive genomic profiling is useful for patients with Thyroid carcinoma (TC) for whom standard treatment has become refractory. We analyzed the clinical and genomic characteristics of patients with TC using the Japanese nationwide Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database. METHODS: This retrospective observational study used the data obtained from the C-CAT database. Genomic information has been accumulated on representative gene mutations associated with TC. RESULTS: Among the 482 patients, 212 (44%) were male and 270 (56%) were female. According to histological type, 259 (54%), 46 (10%), 16 (3%), 51 (11%), and 110 (23%) patients had papillary TC (PTC), follicular TC, medullary TC, poorly differentiated TC, and anaplastic TC (ATC), respectively. Among the genomic profiling tests, FoundationOne CDx (n = 388; 80%) was the most frequently performed. The frequencies of BRAF, NRAS, HRAS, KRAS, and RET mutations were 259 (54%), 62 (13%), 13 (3%), 16 (3%), and 12 (2%), respectively. The BRAF V600E mutation (n = 257) was the predominant BRAF mutation. TERT promoter mutations, which are associated with tumor aggressiveness, were detected in 308 patients (64%). CONCLUSIONS: PTC was the most common histologic type of TC for which genetic profiling was performed in Japan, followed by ATC. Since the most common targetable mutation is the BRAF mutation, practical application of BRAF-targeted therapy can be an important treatment option for Japanese patients with TC.

Role of the Degree of Vascular Invasion in Predicting Prognosis of Follicular Thyroid Carcinoma.

OBJECTIVE: The present study investigated the prognostic factors for follicular thyroid carcinoma (FTC) with the incorporation of the histologic subtype and degree of vascular invasion (VI). PATIENTS: The records of 474 patients with FTC confirmed by surgical specimens at Ito Hospital from January 2005 to December 2014 were reviewed in this retrospective cohort study. The Cox proportional hazard model was used to determine factors associated with disease-free survival (DFS) and distant metastasis-free survival. RESULTS: Of the 474 patients, 140 (30%) had minimally invasive FTC, 260 (55%) had encapsulated angio-invasive FTC, and 74 (16%) had widely invasive FTC. Among the 428 patients with M0 FTC, the 10-year DFS rates of patients with minimally invasive FTC (n = 133), encapsulated angio-invasive FTC (n = 247), and widely invasive FTC (n = 48) were 97.3%, 84.2%, and 69.9% (P < .001), respectively. A multivariate analysis identified aged ≥55 years (hazard ratio [HR], 2.204; 95% CI, 1.223-3.969; P = .009), histologic subtype (HR, 2.068; 95% CI, 1.064-4.021; P = .032), VI of ≥2 (HR, 6.814; 95% CI, 3.157-14.710; P < .001), and tumor size >40 mm (HR, 2.014; 95% CI, 1.089-3.727; P = .026) as independent negative prognostic factors for DFS. CONCLUSION: Our study results may enable us to stratify the prognosis of FTC more accurately by combining the histologic subtype with the degree of VI ≥2, aged ≥55 years, and tumor size >40 mm.

Association of BRAF or TERT Promoter Mutations and Advanced Papillary Thyroid Carcinoma.

BACKGROUND/AIM: BRAF and TERT promoter mutations are associated with the poor prognosis of papillary thyroid carcinoma. This single-center retrospective study investigated the influence of these genes on advanced cases. PATIENTS AND METHODS: Advanced cases who underwent gene panel testing and cases who underwent complete resection were classified as groups A and C, respectively. The gene mutations were determined using gene panel testing or Sanger sequencing using tumor DNA. RESULTS: The study included 51 cases in group A and 44 cases in group C. In group A, all cases had unresectable lesions or distant metastasis; 82.4% of cases showed no accumulation of radioactive iodine in metastasis and 47.1% of cases were administered drug therapy. Meanwhile, all cases of group C did not have distant metastasis. The prevalence of TERT promoter mutations was significantly higher in group A compared to group C (70.6% vs. 18.2%, p<0.001). However, there was no significant difference in the prevalence of BRAF mutations between the two groups (86.3% vs. 90.9%). In Group C, disease-free survival was significantly shorter in patients harboring the TERT promoter mutations (p<0.001), despite no significant difference in that according to the BRAF mutation status. In addition, there was no significant difference in overall survival in group A according to the TERT promoter mutation status. CONCLUSION: Advanced papillary thyroid carcinoma was associated with the TERT promoter mutations, but not with BRAF mutation. Meanwhile, TERT promoter mutations did not affect overall survival among the advanced cases.

Selpercatinib for treating recurrent mixed medullary and follicular cell-derived thyroid carcinoma: a case report.

BACKGROUND: Mixed medullary and follicular cell-derived thyroid carcinoma (MMFCC) is characterized by the coexistence of follicular and C cell-derived tumour cell populations within the same lesion. Due to its rarity, its etiology and clinical course remain unclear, and treatment for advanced or recurrent cases has not been established. CASE PRESENTATION: We report a case of MMFCC treated with selpercatinib. The patient was a 69-year-old male presenting with tumors in the right thyroid lobe and in the upper mediastinum. Fine-needle aspiration (FNA) cytology of the right thyroid lobe tumor revealed a medullary carcinoma; germline RET mutations were not detected. After resection of the right thyroid lobe with central node dissection, rapid intraoperative diagnosis of the mediastinal mass confirmed malignancy, leading to total thyroidectomy with excision of the upper mediastinal tumor. Histologically, the tumor in the right thyroid lobe and the pretracheal lymph node revealed a mixture of medullary and follicular carcinoma components, diagnosed as MMFCC. The mediastinal lymph node exhibited only medullary carcinoma components. At 11 months postoperatively, computed tomography scans showed enlargement of the right supraclavicular and upper mediastinal lymph nodes. FNA cytology of the right supraclavicular lymph node suggested the recurrence of medullary thyroid carcinoma. The gene panel testing (The Oncomine Dx Target Test Multi-CDx system®, Thermo Fisher SCIENTIFIC) of metastatic lymph node revealed RET somatic mutation (M918T). Treatment with selpercatinib was initiated, and both the cervical and mediastinal lymph nodes showed a reduction in size. CONCLUSIONS: We report a rare case of selpercatinib use for MMFCC. Since RET mutations may occur frequently in MMFCC, selpercatinib could be effective in treating MMFCC.

Conversion surgery after lenvatinib treatment for anaplastic thyroid carcinoma: a case report.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is the most aggressive form of thyroid carcinoma. Lenvatinib, a multikinase inhibitor, is rarely used in preoperative settings due to adverse effects including delayed wound healing and fistula formation. Herein, we report the use of lenvatinib treatment prior to conversion surgery for the treatment of ATC. CASE PRESENTATION: A 71-year-old woman was referred to our hospital with suspected thyroid cancer with recurrent laryngeal nerve invasion and cervical lymph node metastasis based on the results of ultrasonography. Computed tomography demonstrated the presence of a thyroid tumor invading the trachea and esophagus with no evidence of distant metastasis. Fine needle aspiration of the left cervical lymph node indicated the lymph node metastasis of ATC. As the tumor had widely invaded the trachea and esophagus, unresectable ATC was diagnosed and treatment with lenvatinib was initiated at a dose of 24 mg/day. On day 13 of lenvatinib treatment, the primary tumor and lymph node metastases demonstrated a partial response to therapy. As the tumor was now considered resectable, the decision was made to perform conversion surgery. Total thyroidectomy and left lateral neck node dissection were performed 7 days after the withdrawal of lenvatinib. The patient was discharged on postoperative day 5 with no complications. Histopathological examination demonstrated that the tumor contained the component of papillary thyroid carcinoma, squamoid ATC cells, and granulation tissue. In areas of granulation tissue, atypical cells with spindle-shaped or polygonal morphology, pyknotic nuclei, and scant cytoplasm were observed. Immunohistochemically, these cells were positive for cytokeratin AE1/AE3, TTF-1, and p53 and negative for thyroglobulin and PAX8. Therefore, the areas of granulation tissue observed within tumor samples were also considered ATC that were affected by lenvatinib treatment. In total, approximately 50% of resected tumor comprised ATC, and 70% of them had been changed to granulation tissue. CONCLUSIONS: The findings in the present case indicate that lenvatinib may have significant antitumor effects in preoperative settings. Lenvatinib may represent a promising candidate therapy for unresectable ATC by increasing tumor resectability.

Validation of EZH2 Inhibitor Efficiency in Anaplastic Thyroid Carcinoma Cell Lines.

BACKGROUND/AIM: The prognosis of anaplastic thyroid carcinoma (ATC) is poor, and there is currently no established treatment to improve its outcome. We previously reported that enhancer of zeste homolog 2 (EZH2) was highly expressed in ATC, and may be a therapeutic target; however, the effects of EZH2 on ATC growth currently remain unknown. MATERIALS AND METHODS: We investigated the effects of an EZH2 inhibitor (DZNep) on four ATC cell lines (8305C, KTA1, TTA1 and TTA2). We performed a gene panel analysis of all ATC cell lines to identify differences in DZNep sensitivity between the cell lines. To investigate the effects of DZNep on the recovery of differentiation, we assessed changes in thyroid differentiation markers (TDMs) before and after the DZNep treatment using PCR. RESULTS: EZH2 was expressed in all ATC cell lines. The cell-reducing effects of DZNep were detected in all ATC cell lines, and were the strongest in KTA1 cells followed by TTA2 cells. The TTA1 and 8305C cell lines, which showed weak cell-reducing effects, had TP53 mutations. No changes in TDMs were observed in any ATC cell line. CONCLUSION: DZNep, an EZH2 inhibitor, exerted suppressive effects on the growth of ATC cell lines and has potential as a therapeutic strategy; however, its effects may be attenuated in ATC with TP53 mutations.