Effects of Anti-Cancer Drug Sensitivity-Related Genetic Differences on Therapeutic Approaches in Refractory Papillary Thyroid Cancer.

Thyroid cancer (TC) includes tumors of follicular cells; it ranges from well differentiated TC (WDTC) with generally favorable prognosis to clinically aggressive poorly differentiated TC (PDTC) and undifferentiated TC (UTC). Papillary thyroid cancer (PTC) is a WDTC and the most common type of thyroid cancer that comprises almost 70-80% of all TC. PTC can present as a solid, cystic, or uneven mass that originates from normal thyroid tissue. Prognosis of PTC is excellent, with an overall 10-year survival rate >90%. However, more than 30% of patients with PTC advance to recurrence or metastasis despite anti-cancer therapy; consequently, systemic therapy is limited, which necessitates expansion of improved clinical approaches. We strived to elucidate genetic distinctions due to patient-derived anti-cancer drug-sensitive or -resistant PTC, which can support in progress novel therapies. Patients with histologically proven PTC were evaluated. PTC cells were gained from drug-sensitive and -resistant patients and were compared using mRNA-Seq. We aimed to assess the in vitro and in vivo synergistic anti-cancer effects of a novel combination therapy in patient-derived refractory PTC. This combination therapy acts synergistically to promote tumor suppression compared with either agent alone. Therefore, genetically altered combination therapy might be a novel therapeutic approach for refractory PTC.

Synergistic Anticancer Activity of N-Hydroxy-7-(2-Naphthylthio) Heptanomide, Sorafenib, and Radiation Therapy in Patient-Derived Anaplastic Thyroid Cancer Models.

Anaplastic thyroid cancer (ATC) is an undifferentiated and advanced form of thyroid cancer, accompanied with a high ratio of epigenetic adjustment, which occurs more than genetic mutations. In this study, we aimed to evaluate the synergistic anticancer effect (in vitro and in vivo) of the new combination of N-hydroxy-7-(2-naphthylthio) heptanomide (HNHA) and sorafenib with radiation therapy in pre-clinical models of ATC. The ATC cell lines, YUMC-A1 and YUMC-A2, were isolated from the current patients who were treated with HNHA and sorafenib, either as monotherapy or combination therapy. Synergistic anticancer effect of the combination therapy on the intracellular signaling pathways and cell cycle was assessed via flow cytometry and immunoblot analysis. To examine tumor shrinkage activity in vivo, an ATC cell line-derived mouse xenograft model was used. Results showed that the combination therapy of HNHA and sorafenib with radiation promoted tumor suppression via caspase cleavage and cell cycle arrest in patient-derived ATC. In addition, the combination therapy of HNHA and sorafenib with radiation was more effective against ATC than therapy with HNHA or sorafenib with radiation. Thus, the combination of HNHA and sorafenib with radiation may be used as a novel curative approach for the treatment of ATC.

Synergistic anticancer activity of sorafenib, paclitaxel, and radiation therapy on anaplastic thyroid cancer in vitro and in vivo.

BACKGROUND: This study aimed to investigate the antitumor activity of paclitaxel with radiation and sorafenib in anaplastic thyroid cancer (ATC) cells in vitro and in vivo. METHODS: The 8505C ATC cell line was exposed to radiation, sorafenib, and paclitaxel each or in combination. The effects of combined treatment on the cell cycle and intracellular signaling pathways were assessed using flow cytometry and western blot analysis. An ATC cell line xenograft model was used to examine antitumor activity in vivo. RESULTS: Radiation, paclitaxel plus sorafenib synergistically decreased cell viability in ATC cells and significantly increased apoptotic cell death. The combination of paclitaxel, sorafenib with radiation reduced the antiapoptotic factor in ATC. This combination therapy significantly reduced the tumor volume and increased survival in the ATC xenograft model. CONCLUSIONS: These results suggest that the combination of radiation and paclitaxel plus sorafenib has significant anticancer activity in preclinical models.

Thyroid Hormone Supplementation Therapy for Differentiated Thyroid Cancer After Lobectomy: 5 Years of Follow-Up.

Background: Lobectomy with preservation of the contralateral lobe has already become the most preferred surgical method for patients with low-risk thyroid cancer. The incidence of and risk factors for the development of hypothyroidism after lobectomy for thyroid cancer remains unclear. The previous practice of levothyroxine supplementation post-thyroidectomy, to bring about thyroid stimulating hormone (TSH) suppression, had some serious side effects. This study aimed to evaluate the incidence of hypothyroidism and to identify the factors associated with hypothyroidism requiring thyroid hormone replacement. Methods: We retrospectively reviewed the charts of 256 consecutive patients with differentiated thyroid cancer treated with lobectomy at the Gangnam Severance Hospital between April and December 2014 who were followed-up for more than 5 years. Patients were evaluated using a thyroid function test at the time of outpatient visit every 6 months for the 1st year, with an annual follow-up thereafter. Results: After 5 years, 66.0% (169) of the patients needed levothyroxine supplementation to maintain euthyroid status. The incidence of hypothyroidism requiring levothyroxine supplementation increased until 3 years but showed no significant change in the 4 and 5th year. Recurrence showed no difference between the group with and without levothyroxine supplementation. The presence of thyroiditis and preoperative TSH levels were correlated with postoperative levothyroxine supplementation to maintain euthyroid status, in univariate and multivariate analyses. Conclusion: High preoperative TSH levels and/or thyroiditis indicate a significantly increased likelihood of developing hypothyroidism requiring thyroid hormone supplementation after a thyroid lobectomy. Patients with an increased risk of postoperative hypothyroidism must be aware of their risk factors and should undergo more intensive follow-ups.

SoLAT (Sorafenib Lenvatinib alternating treatment): a new treatment protocol with alternating Sorafenib and Lenvatinib for refractory thyroid Cancer.

BACKGROUND: In the last decade, several tyrosine kinase inhibitors (TKIs), which disrupt pathways involved in the proliferation and tumorigenesis of thyroid cancer, have been extensively studied. Two different TKIs, lenvatinib and sorafenib, were recently approved by both the US FDA and European Medicine Agency. Until date, the duration of the TKI response is not sufficient and resistance eventually occurs. The goal of this study was to investigate a new treatment protocol, SoLAT, using sorafenib and lenvatinib alternatively on refractory thyroid cancer. METHODS: Patient-derived aggressive papillary thyroid cancer (PTC) cell lines from patients with biochemical and histologically proven aggressive RAI-refractory papillary thyroid cancer were exposed to sorafenib and lenvatinib alternatively. Human thyroid cancer cell xenografts were obtained by injecting patient-derived aggressive PTC cell lines into the flank of female BALB/c nude mice. Tumor-bearing mice were treated with sorafenib and lenvatinib alternatively. Cell viability assay, immunofluorescence analysis, confocal imaging, immunoblot analysis, flow cytometry analysis of cell cycle and a tube formation assay were performed. RESULTS: SoLAT was more effective for advanced PTC cell lines than individual treatment. Immunoblot analysis showed that SoLAT markedly increased levels of cell cycle inhibitors (p53 and p21), and pro-apoptotic factors (Apaf-1 and cleaved caspase 3) and decreased levels of positive cell cycle regulators (cyclin D1, CDK4, CDK6) and anti-apoptotic factors (p-NFκB, Bcl-2). Increased sub-G0/G1 population was observed in the SoLAT group, leading to apoptosis, cell cycle arrest, and strong inhibition of advanced PTC cell viability. SoLAT reduced the level of EMT markers such as vimentin, E-cadherin, Snail and Zeb1 by FGFR inhibition. In the xenograft model, individual treatment with sorafenib or lenvatinib did not markedly suppress patient-derived aggressive PTC cell xenograft tumors, whereas SoLAT significantly suppressed the proliferation of these tumors. CONCLUSIONS: SoLAT was more effective than individual treatment with sorafenib or lenvatinib in inhibiting PTC progression by inducing cell cycle arrest. Studies using both in vitro cell culture and an in vivo xenograft model provided evidence of tumor shrinkage with SoLAT. We suggest that these effects may be due to reduced EMT-mediated drug resistance in the aggressive PTC model.

Parathyroid score can predict the duration of required calcium supplementation after total thyroidectomy.

BACKGROUND: Postoperative hypoparathyroidism is the most common complication after total thyroidectomy, owing to unintentional injury or decreased blood flow to the parathyroid glands. Prediction of postoperative hypoparathyroidism would be helpful for surgeons to manage postoperative hypocalcemia. In this study, we scored the discoloration of the parathyroid glands using a new parathyroid scoring system and evaluated the correlation between the parathyroid score and duration of required calcium supplementation after total thyroidectomy. METHODS: A total of 316 patients undergoing total thyroidectomy between November 2009 and April 2010 were enrolled in this retrospective study. Parathyroid scoring was performed by one experienced surgeon. The status of each of the 4 parathyroid glands was classified as normal color (3 points), slightly discolored (2 points), dark discoloration (1 point), or loss of the gland (0 points), resulting in possible total scores of 0-12. Serum parathyroid hormone (PTH), serum calcium, and ionized calcium concentrations were measured at 2 hours, 2 weeks, 3 months, 6 months, and 1 year after surgery. Patients were also divided into three groups based on the duration of required calcium supplementation: no required supplementation (n = 260, 82.3%), required supplementation for <6 months (n = 38, 12%), and required supplementation for ≥6 months (n = 18, 5.75%). RESULTS: Parathyroid scores were positively correlated with ionized PTH concentrations at 2 hours (r = 0.053, p < 0.001), 2 weeks (r = 0.056, p < 0.001), 3 months (r = 0.032, p<0.001), 6 months (r = 0.072, p < 0.001), and 1 year (r = 0.071, p < 0.001) after thyroidectomy. Parathyroid scores were significantly and inversely associated with the duration of required calcium supplementation (p = 0.001). CONCLUSIONS: Parathyroid scores at the end of surgery might be helpful for predicting the degree of postoperative hypocalcemia after total thyroidetomy.

Changing trends in the management of well-differentiated thyroid carcinoma in Korea.

A questionnaire administered in 2009 found that members of the Korean Association of Thyroid-Endocrine Surgeons (KATES) favored more aggressive treatment of well-differentiated thyroid carcinoma (WDTC) than physicians from other countries. This study assessed the changes in practical management of WDTC in Korea from the previous survey. Questionnaires were sent by e-mail to KATES members. A total of 101 members completed the questionnaire. Their responses were compared with response for the 2009 survey. Of the respondents, 53.5% and 80.2% indicated that they would perform fine-needle aspiration cytology on nodules that were <0.5 cm and 0.5-1.0 cm in diameter, respectively. If the cytology was positive, a large number of respondents favored surgical treatment, regardless of tumor size. Compared with the 2009 survey, a slightly higher percentage favored observation for patients with tumors that were <0.5 cm in diameter, and a larger percentage recommended less-than-total thyroidectomy for patients with T1 cancers. Respondents in 2014 favored aggressive lymph node dissection less, irrespective of tumor size, preferring short-term treatment with thyroid stimulating hormone suppressors. The percentage preferring postoperative high-dose radioactive iodine therapy slightly increased, whereas the percentage favoring external irradiation decreased, in 2014 compared with 2009. The management of Korean patients with WDTC changed from 2009 to 2014. In 2009, Korean respondents favored more aggressive treatment of WDTC compared with respondents from other countries. In 2014, however, Korean respondents favored a more conservative approach, especially in patients with microcarcinomas.

Recovery from Permanent Hypoparathyroidism After Total Thyroidectomy.

BACKGROUND: Permanent hypoparathyroidism after total thyroidectomy is a rare but potentially serious iatrogenic complication. The aim of this study was to investigate the rate of recovery from postoperative, permanent hypoparathyroidism in patients undergoing thyroidectomy without parathyroid autotransplantation. METHODS: This study was a prospective case series with a postoperative follow-up of up to 3 years. We enrolled patients with thyroid cancer who underwent total thyroidectomy with central compartment dissection, with or without lateral neck dissection, and who had postoperative permanent hypoparathyroidism, defined as serum levels of intact parathyroid hormone (PTH) <15 pg/mL for at least 1 year. In the postoperative follow-up period, the serum levels of PTH and calcium were measured regularly. Recovery from permanent hypoparathyroidism was defined as return to normal serum levels of PTH (15-65 pg/mL) and calcium (8.5-10.1 mg/dL) without calcium and/or vitamin D supplementation. RESULTS: In the 1467 patients who underwent total thyroidectomy, 22 presented with permanent postoperative hypoparathyroidism. In 5 of these 22 patients, the PTH levels increased steadily and returned to normal in 27.6±2.9 months, after which supplementation of calcium and vitamin D could be discontinued. CONCLUSIONS: Although recovery from permanent hypoparathyroidism is rare, patients should be monitored for serum PTH levels so that unnecessary treatments such as calcium and vitamin D supplementation can be avoided.

Low iodine diet for one week is sufficient for adequate preparation of high dose radioactive iodine ablation therapy of differentiated thyroid cancer patients in iodine-rich areas.

BACKGROUND: Most current guidelines suggest one or two weeks of low iodine diet (LID) before radioactive iodine ablation therapy (RAIT) to increase its efficacy in differentiated thyroid cancer (DTC) patients after total thyroidectomy. LID duration is particularly important for patients living in iodine excess areas. However, there is no standardized LID protocol and there are limited reports regarding the relationship between LID and ablation outcome. Therefore, we aimed to evaluate the optimal LID duration and define clinical features that affect ablation outcome. METHODS: A total of 202 papillary thyroid cancer patients with total thyroidectomy preparing for RAIT were enrolled. All patients had undergone two weeks of LID before (131)I administration. Morning spot urine specimens were obtained twice (one week or two weeks after LID, respectively) from each patient. Urine iodine excretion (UIE) values were used to evaluate LID efficacy. Successful ablation was defined using two definitions: (i) no visible uptake on a follow-up diagnostic (131)I scans, and (ii) no visible uptake on a follow-up diagnostic (131)I scans and stimulated serum thyroglobulin (Tg) levels <1 ng/mL. RESULTS: The UIE median values after LID for one and two weeks were lower than 50 µg/L, and the median UIE values were not significantly different according to the LID duration. Based on the first criterion for successful ablation, 175 of the 195 patients were successfully ablated. There were no significant differences in mean and median UIE levels between the ablated and non-ablated groups after LID for two weeks. The rate of ablation did not differ between the mild and moderate iodine deficient groups. Based on the second criterion for successful ablation, 149 of 188 patients were successfully ablated. The ablation success rate did not differ between UIE levels. When we analyzed clinical factors that affect ablation outcome, serum Tg level at the time of ablation was the only significant variable in multivariate logistic analysis. CONCLUSION: Strict LID for one week was sufficient to achieve target UIE values for RAIT preparation, even in iodine-rich areas.