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.

Impact of Age on Prognosis in Papillary Thyroid Carcinoma: How Should Age be Incorporated into the Treatment Strategy?

BACKGROUND: Age has been recognized as one of the strong prognostic indicators for thyroid cancer. However, treatment strategies for papillary thyroid cancer (PTC) are usually determined only by the extent of disease progression, without considering the patient's age. The aim of this study was to investigate how the surgical strategy for PTC should take into account patient age. METHODS: To exclude the effect of treatment strategy, 837 patients treated with uniform treatment strategies (hemithyroidectomy without radioiodine therapy) between 1986 and 1995 were the subjects of this study. Using a Cox proportional hazard model, clinical risk factors related to disease-specific survival (DSS), disease-free survival (DFS), and distant metastasis-free survival (DMFS) were analyzed. A receiver-operating characteristic (ROC) curve analysis was performed to identify the optimal cutoff points. RESULTS: Significant risk factors related to DSS and DMFS were age, extrathyroidal extension (ETE), and numbers of metastatic lymph nodes (NMLNs), but age was not significantly related to DFS. The 20-year DSS and DMFS rates were fair in patients without ETE regardless of age or NMLNs. However, in patients with ETE, DSS and DMFS rates were significantly worse in elderly patients than in young patients. ROC curve analysis showed that the optimal cutoff age was 48 years for discriminating DSS in patients with ETE. CONCLUSION: Regardless of age, PTC patients without ETE are candidates for a treatment strategy not using RAI, and more aggressive treatment may be recommended for elderly PTC patients with ETE.

Evaluation of factors predicting postoperative recurrence and metastasis of parathyroid cancer: a single-center study.

PURPOSE: The purpose of this study was to examine the postoperative clinical course of parathyroid carcinoma to determine factors that predict postoperative recurrence and distant metastasis. METHODS: In this retrospective study, we included 38 patients with parathyroid carcinoma who received surgical intervention at Itoh Hospital between 1979 and 2020. Clinicopathologic characteristics (age, sex, intact PTH, serum Ca level, operation type, parathyroid weight, parathyroid size, histopathologic findings: vascular invasion, capsular invasion, necrosis, histological type, and Ki-67 staining) were used. The median follow-up observation period was 63.7 months. RESULTS: Postoperatively, 5 patients (13.2%) developed distant metastasis or had localized recurrence, and 3 patients died (7.9%). The results of the univariate analysis revealed three factors affecting distant metastasis and recurrence, which were Ki-67 (p = 0.0041), the presence or absence of necrosis (p = 0.0163), and tumor weight (p = 00,189). Using the cutoff values obtained by ROC analysis, which were 4.1 for Ki-67 (sensitivity of 80% and specificity of 96.9%) and 4890 mg for tumor weight (sensitivity of 100% and specificity of 60.9%), we calculated the cumulative incidence of recurrence and distant metastasis by the three factors retained. We found that the presence of the three factors was associated with a high possibility of distant metastasis or recurrence during the 5-year follow-up period. CONCLUSIONS: Three factors, Ki-67, necrosis, and tumor weight in parathyroid carcinoma, may predict outcomes of postoperative recurrence and distant metastasis.

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.

Predictors of maximum efficacy of lenvatinib for real-world patients with differentiated thyroid carcinoma.

BACKGROUND AND OBJECTIVES: Tyrosine kinase inhibitors (TKIs) have provided excellent clinical benefits to patients with advanced differentiated thyroid cancer (DTC): however, the tumor status for which maximum efficacy can be obtained remains controversial. We conducted this study to identify effective clinical predictors, focusing on disease progression. METHODS: Using the data of 42 DTC patients treated with lenvatinib, we investigated the clinical factors related to overall survival (OS) and progression-free survival (PFS), and conducted analyses by the scoring of the factors. RESULTS: The 3 year OS and median PFS were 51% and 13.8 months, respectively. Univariate analysis identified performance status (PS), tumor-related symptoms, and tumor diameter as the only factors affecting both these outcomes. Giving 1-point for each of these three factors, a higher score was significantly related to shorter OS and PFS. Patients with two or fewer points (n = 34) had better median OS (NR vs 3.9 months, p < 0.001) and PFS (15.7 vs 2.1 months, p < 0.001) than patients with three points (n = 8). Patients with all three factors had a significantly worse prognosis than patients with two or fewer factors. CONCLUSION: DTC patients with all three indicators are unlikely to have longer survival. Therefore, it is important to commence TKIs before disease progression.

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.

Urinalysis by combination of the dipstick test and urine protein-creatinine ratio (UPCR) assessment can prevent unnecessary lenvatinib interruption in patients with thyroid cancer.

BACKGROUND: Proteinuria induced by lenvatinib is a class effect that occurs secondary to VEGFR suppression. Withholding of lenvatinib is required in cases with severe proteinuria. Urine protein-creatinine ratio (UPCR, g/gCre) has recently attracted attention as an alternative to 24-h urine collection for assessing proteinuria. The aim of this study was to examine the correlation between the results of proteinuria assessed by the dipstick test and UPCR, and to investigate the influence of proteinuria grading with UPCR on lenvatinib dose adjustment compared to that with only the dipstick test. METHOD: Three hundred and ten urine samples from 63 patients with advanced thyroid cancer under treatment with lenvatinib, which were tested by both the dipstick test and UPCR were analyzed. Lenvatinib was withheld when there was evidence of CTCAE grade 3 proteinuria, and restarted when it resolved. The frequency of proteinuria, correlation between the results of the dipstick test and UPCR test, and the effect of dose withholding in cases with results of 3 + in the dipstick test were calculated. RESULTS: Proteinuria was seen in 56 (88.9%) patients. Of the 154 dipstick 3 + samples, only 56 (36.4%) were judged as more than 3.5 g/gCre by UPCR (grade 3 proteinuria), although none of the 1 + and only 3.7% of 2 + samples were judged as grade 3 proteinuria. We were able to prevent unnecessary lenvatinib interruption due to proteinuria in 63.6% of dipstick 3 + samples by assessment of UPCR. CONCLUSIONS: Urinalysis by combination of the dipstick test and UPCR assessment might be a better strategy for preventing unnecessary interruption of lenvatinib.

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.

Prognostic Impact of the Turin Criteria in Poorly Differentiated Thyroid Carcinoma.

BACKGROUND: The Turin criteria including solid, trabecular, and/or insular architecture, lack of typical nuclear features of papillary carcinoma, and mitoses, necrosis, or convoluted nuclei were adopted in the recent 4th edition of the World Health Organization classification published in 2017. MATERIALS AND METHODS: Between 2006 and 2017, 11,001 cases underwent initial surgery for primary malignant thyroid tumor derived from follicular cells. A total of 75 (0.7%) cases were diagnosed with PDTC according to the 2004 WHO classification. Based on the Turin criteria, 30 (40%) cases were re-classified as PDTC-Turin (+) and 45 (60%) cases were PDTC-Turin (-). Clinicopathological features and prognosis were compared between PDTC-Turin (+) and PDTC-Turin (-). RESULTS: Seventy-five patients (48 females and 27 males) had a median age at the time of surgery of 57 years. Preoperative diagnosis was benign in 16 (21%), follicular tumor in 40 (53%), and malignant in 19 (25%). The 5-year cause-specific survival (CSS) and disease-free survival (DFS) rates were 97% and 44% for PDTC-Turin (+) and 100% and 88% for PDTC-Turin (-). On univariate analysis, CSS and DFS rates were significantly worse in the PDTC-Turin (+) than in the PDTC-Turin (-) (p = 0.0096, and p = 0.0016). Multivariate analysis showed that Turin criteria status, Ki-67 labeling index ≥ 10%, and age 55 ≥ years were the independent prognostic factors for recurrence. CONCLUSIONS: The prevalence of PDTC diagnosed with the Turin criteria was low, but it showed more aggressive behavior. The 2017 WHO classification reflects the prognosis more accurately than the 2004 WHO classification.

Usefulness of Stereotactic Radiotherapy Using the CyberKnife for Patients with Inoperable Locoregional Recurrences of Differentiated Thyroid Cancer.

BACKGROUND: Surgical resection is the preferred treatment for locoregional recurrence of differentiated thyroid cancer (DTC). However, some recurrences are unresectable because of their aggressive invasion or severe adhesions. On the other hand, stereotactic radiotherapy (SRT) enables high-dose irradiation to target lesions, and its usefulness for various cancers has been reported. The objective of the present study was to investigate the feasibility and efficacy of SRT as salvage treatment for locoregional recurrence of DTC. METHODS: Between August 2011 and December 2017, 52 locoregional recurrent lesions in 31 patients with recurrent DTC were treated by SRT using the CyberKnife system. Information on the adverse events associated with SRT was retrospectively collected from the patients' medical records. Of the 52 lesions, 33 could be evaluated for therapeutic effectiveness by follow-up CT, and response was assessed using the RECIST criteria. RESULTS: Twenty-five patients had papillary carcinoma, 5 had follicular carcinoma, and 1 had poorly differentiated cancer. SRT was delivered in one to 20 fractions, and the median dose was 30 Gy (range 15-60 Gy). Adverse events were not frequent, but 1 patient developed bilateral vocal cord palsy that required emergent tracheostomy. The median follow-up period of 33 lesions was 14 months (range 1-54 months). Complete response, partial response, stable disease, and progressive disease were seen in 10, 11, 9, and 3 patients, respectively. The 3-year local control rate was 84.6%. CONCLUSION: SRT using the CyberKnife system was found to be a feasible and effective treatment to suppress the growth of locoregional recurrence of DTC.

Change of surgical strategy for Graves' disease from subtotal thyroidectomy to total thyroidectomy: a single institutional experience.

The extent of thyroidectomy in Graves' disease remains controversial. In our institution, long-term euthyroidism without thyroxin replacement therapy has been the aim, and it has long been the standard surgical procedure used to treat Graves' disease in many institutions, including our hospital. Based our several clinical studies, it was concluded that subtotal thyroidectomy is not suitable as a standard surgical procedure for the treatment of Graves' disease. In 2009, the surgical strategy for Graves' disease was changed from subtotal thyroidectomy to total thyroidectomy in our hospital. In this study, how surgical complications have changed after this modification was examined. The subjects were 1,476 patients with Graves' disease treated by thyroidectomy between 2006 and 2014. There were 1,119 females and 357 males with a median age of 39 years. A total of 660 patients underwent bilateral subtotal thyroidectomy (ST group), and 816 patients underwent total thyroidectomy (TT group). Both transient hypocalcemia and prolonged hypocalcemia were observed significantly more frequently in the TT group than in the ST group (p < 0.001). Total thyroidectomy was identified as risk factors for prolonged hypocalcemia on multivariate analysis. In conclusion, total thyroidectomy is a reliable and effective therapy for controlling hyperthyroidism in terms of controlling of hyperthyroidism. However, it should be noted that total thyroidectomy resulted in increased rate of prolonged hypocalcemia. Surgeons should try to reduce the surgical complication rate as much as possible.

Clinical Status and Treatment of Liver Metastasis of Differentiated Thyroid Cancer Using Tyrosine Kinase Inhibitors.

BACKGROUND: Treatment of patients with liver metastasis of differentiated thyroid carcinoma (DTC) has not been sufficiently defined, because liver metastasis of DTC has been described mostly as case reports. Additionally, such patients are considered end-of-treatment responders. A relatively new approach using tyrosine kinase inhibitors (TKIs) may provide opportunities to manage systemic metastasis. This study aims to define the clinical features of DTC patients with liver metastasis and evaluate the benefits of TKIs. METHODS: We retrospectively analyzed clinical features of 29 patients (mean age 67.8 years) diagnosed with liver metastasis of DTC at our institution between January 1981 and May 2017. RESULTS: All patients had distant metastasis at other organ sites upon diagnosis of liver metastasis; 41% of them developed new metastasis afterward. Management after diagnosis of liver metastasis comprised palliative care (48%), radioactive iodine therapy (28%), and TKI therapy (24%). The median survival after diagnosis of liver metastasis was only 4.8 months. Survival rates were significantly better in patients with performance statuses between 0 and 2 on the Eastern Cooperative Oncology Group scale at diagnosis of liver metastasis (n = 22, 76%) treated with TKI compared to those who were not (P = 0.017; log-rank test; hazard ratio 0.19). One-year survival rates were 71.4 and 26.7% for patients treated with or without TKI, respectively. CONCLUSIONS: Patients with liver metastasis had poor clinical prognosis. When other distant metastases existed at diagnosis of liver metastasis, TKI therapy was considered an effective therapeutic option for patients with liver metastasis of DTC.

Cribriform-Morular Variant of Papillary Thyroid Carcinoma: Clinical and Pathological Features of 30 Cases.

BACKGROUND: Cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC) is rare; it may occur in cases of familial adenomatous polyposis (FAP) or be sporadic. To clarify the clinicopathological features of CMV-PTC, the medical records of these patients were investigated retrospectively. MATERIALS AND METHODS: Between 1979 and 2016, a total of 17,062 cases with PTC underwent initial surgery at Ito Hospital. Of these, 30 (0.2%) cases histologically diagnosed with CMV-PTC were reviewed. RESULT: The patients were all women, with a mean age at the time of surgery of 24 years. Seven (23%) cases were thought to have FAP because they had colonic polyposis or a family history of FAP or APC gene mutation. The remaining 23 (77%) were thought to be sporadic. Multiple tumors were detected in 6 cases, with a solitary tumor in 24. One patient had lung metastasis at diagnosis. Eleven patients underwent total thyroidectomy or subtotal thyroidectomy, and 19 underwent lobectomy. Twenty-six (87%) patients underwent neck lymph node dissection. Three patients had tumor metastasis in central lymph nodes, but these were incidentally detected metastatic classical PTC (cPTC) based on histological examination. In this series, there were no cases of LN metastases of CMV-PTC. During a mean follow-up of 15 years, one patient had new cPTC in the remnant thyroid after initial surgery, and the other patients showed no signs of recurrence. CONCLUSION: CMV-PTC occurred in young women, their long-term prognosis was excellent. Total thyroidectomy is recommended for FAP-associated CMV-PTC, but modified neck lymph node dissection is not necessary.

Clinical factors related to the efficacy of tyrosine kinase inhibitor therapy in radioactive iodine refractory recurrent differentiated thyroid cancer patients.

New insights in thyroid cancer biology propelled the development of targeted therapies as salvage treatment for radioiodine-refractory differentiated thyroid cancer (RR-DTC), and the tyrosine kinase inhibitor (TKI) lenvatinib has recently become available as a new line of therapy for RR-DTC. The aim of this study is to investigate clinical factors related to the efficacy of TKI therapy in recurrent RR-DTC patients and identify the optimal timing for the start of TKI therapy. The subjects consisted of 29 patients with progressive RR-DTC, 9 males and 20 females, median age 66 years. A univariate analysis was conducted in relation to progression free survival (PFS) and overall survival (OS) by the Kaplan-Meier method for the following variables: age, sex, histology of the primary tumor, thyroglobulin doubling time before the start of lenvatinib therapy, site of the target lesions, presence of a tumor-mediated symptom at the start of lenvatinib therapy, and baseline tumor size of the target lesions. Median duration of lenvatinib therapy was 14.7 months and median drug intensity was 9.5 mg. At the time of the data cut-off for the analysis, 9 patients (31.0%) have died of their disease (DOD), and a PR (partial response), SD (stable disease), and PD (progressive disease) were observed in 20 patients (69%), 6 patients (20.7%), 3 patients (10.3%), respectively. Univariate analyses showed that the presence of a symptom was the only factor significantly related to poorer PFS and OS. Clinical benefit of TKI therapy will be possibly limited when the therapy starts after tumor-mediated symptoms appear.

Lenvatinib induces early tumor shrinkage in patients with advanced thyroid carcinoma.

Although advanced thyroid carcinoma patients who cannot be cured by conventional therapy have lacked effective treatment, multitargeted tyrosine kinase inhibitors have recently become available. Phase 3 trials of lenvatinib showed a median time to objective response of 2 (95 % confidence interval (CI) 1.9-3.5) months, demonstrating that shrinks tumors rapidly. The phenomenon of immediate tumor shrink is known as early tumor shrinkage (ETS) which is related to clinical outcome in other malignancies. However, precisely when within 8 weeks lenvatinib starts to affect tumors remains unclear. In tumors near the carotid arteries, trachea, or esophagus, a rapid therapeutic effect can induce fistula formation or arterial bleeding. To prevent such treatment-emergent serious adverse events (SAE), early imaging evaluation seems to be very important. In this study, the point in time when lenvatinib started to shrink tumors was retrospectively investigated. The subjects were 16 patients who started lenvatinib administration between May and August 2015. Tumor size was evaluated by computed tomography (CT) scans frequently within the first 8 weeks according to the Response Evaluation Criteria In Solid Tumors (RECIST) guideline. Initial tumor response was defined as ≥ 10% tumor reduction. Serum thyroglobulin (Tg) level was monitored in 8 differentiated thyroid carcinoma (DTC) without TgAb patients. At the first evaluation, 13 patients (83.3 %) showed tumor reduction and that decreased with time. Thirteen patients (83.3 %) showed >10 % tumor reduction within 8 weeks. In all DTC patients, serum Tg level was markedly decreased. In conclusion, lenvatinib immediately shrinks tumors, the so-called ETS phenomenon. Therefore, careful attention should be paid to fistula formation from the early phase.