Identifying the tumor-progressive gene expression profile in high-risk papillary thyroid cancer.

PURPOSE: Papillary thyroid cancer (PTC) is generally associated with a favorable prognosis. However, some patients have fatal disease, with locally infiltrating tumors or progressive distant metastases; yet few studies have investigated the characteristics of the tumor-progressive gene expression profile in advanced PTC. We conducted this study to clarify the gene expression status in advanced PTC and identify candidate molecules for prognostic biomarkers. METHODS: We analyzed 740 tumor-progressive gene expression levels from formalin-fixed paraffin-embedded blocks of samples from six patients with low-risk PTC and six patients with high-risk PTC, using the nCounter PanCancer Progression panel. Then, we investigated the association between the expression levels of focused genes and pathological factors in PTC patients in The Cancer Genome Atlas (TCGA) database. RESULTS: The expression levels of 14 genes in the high-risk PTC specimens were more than two-fold those in the low-risk PTC specimens. In the TCGA database, expression levels of four genes (CCL11, COL6A3, INHBA, and SRPX2) were significantly higher in patients with advanced PTC. Among the patients with advanced PTC, those with high SRPX2 expression levels had poor disease-free survival. Univariate and multivariate analyses revealed that high SRPX2 expression was an independent prognostic factor. CONCLUSION: Based on the findings of this study, CCL11, COL6A3, INHBA, and SRPX2 are potential biomarkers that indicate advanced PTC. SRPX2, in particular, is considered a prognostic biomarker.

Obesity does not affect peri- and postoperative outcomes of transabdominal laparoscopic adrenalectomy.

Laparoscopic adrenalectomy is the gold standard procedure for most adrenal tumors. Obesity is considered as a risk factor for surgical complications. This study aimed to evaluate whether obesity affects peri- and postoperative outcomes of transabdominal laparoscopic adrenalectomy using body mass index (BMI). This retrospective study included 98 patients who underwent transabdominal laparoscopic adrenalectomy between January 2011 and December 2016. We divided the patients into 2 groups: non-obese group (BMI < 25 kg/m2) and obese group (BMI ≥ 25 kg/m2). We assessed perioperative outcomes and postoperative complications between the groups. A total of 98 patients were analyzed (70 without obesity and 28 with obesity). There were no significant differences between the non-obese and obese groups regarding operative time (111 vs 107 min; p = 0.795), blood loss (3.5 vs 3.5 ml; p = 0.740), rate of placement of additional trocars (14.3% vs 17.9%; p = 0.657), rate of open conversion (2.6% vs 3.6%; p = 0.853), and postoperative length of hospital stay (6 vs 5 days; p = 0.237). Furthermore, obesity was not a significant risk factor for postoperative complications (postoperative bleeding, wound infection, and pneumonia). There are no significant differences in peri- and postoperative outcomes of transabdominal laparoscopic adrenalectomy in patients with obesity compared with those without obesity. Transabdominal laparoscopic adrenalectomy is feasible and safe for patients with obesity.

Long-term response to MEK inhibitor monotherapy in a patient with papillary thyroid carcinoma harboring BRAF V600E mutation.

Solid tumors harboring mutations in the Braf gene (BRAF) are currently treated by combination Braf/MEK inhibitor therapy, and there is an extensive literature on patient response rates. Alternatively, few studies have documented the clinical response of BRAF mutation-positive solid tumors to MEK inhibitor monotherapy. We report the case of a 57-year-old female diagnosed with papillary thyroid carcinoma and progressive lung metastases initially treated by total thyroidectomy and subsequent thyroid-stimulating hormone suppression therapy. Next-generation sequencing revealed that the tumor harbored a BRAF V600E mutation, and the patient was enrolled in a clinical study of the oral MEK1/2 inhibitor binimetinib. Shortly after starting treatment, the patient experienced pneumothorax due to rapid regression of lung metastases, and computed tomography after 6 months of binimetinib treatment revealed a partial sustained response. One year later, the dose was reduced because of an acneiform rash. After 5 years of binimetinib treatment, lung metastases had regrown, and treatment was switched to the oral multikinase inhibitor lenvatinib. This case demonstrates the potential of MEK inhibitor monotherapy as an alternative treatment for BRAF mutation-positive papillary thyroid carcinoma.

Flavonoids from the leaves and stems of Sedum japonicum var. senanense and their antioxidant activity.

Twenty flavonoids (1-20) were isolated from the leaves and stems of Sedum japonicum var. senanense endemic to Japan. Among them, nine compounds were reported in nature for the first time, and identified as herbacetin 3-O-neohesperidoside-8-O-(2‴-acetylxyloside) (2), gossypetin 8-O-(2″-acetylxyloside) (4), gossypetin 8-O-(3″-acetylxyloside) (5), gossypetin 3-O-glucoside-8-O-(3‴-acetylxyloside) (9), gossypetin 3-O-glucoside-8-O-(2‴,3‴-diacetylxyloside) (10), gossypetin 3-O-neohesperidoside-8-O-xyloside (11), gossypetin 3-O-neohesperidoside-8-O-(2⁗-acetylxyloside) (12), gossypetin 3-O-neohesperidoside-8-O-(3⁗-acetylxyloside) (13) and gossypetin 3-O-glucoside-8-O-xylofuranoside (14) by UV spectral survey, HR-MS, LC-MS, acid hydrolysis, NMR including 1H and 13C NMR, COSY, NOESY, HSQC and HMBC. Moreover, nine major flavonoids were surveyed for antioxidant activity by H-ORAC method. As the results, gossypetin 3-O-glucoside-8-O-(2‴-acetylxyoside) (8) showed the highest antioxidant activity. Conversely, gossypetin 3-O-neohesperidoside-8-O-xyloside (11) and gossypetin 3-O-neohesperidoside-8-O-(2⁗-acetylxyloside) (12) which attach neohesperidose showed the lowest values.

Involvement of the vagus nerve and hepatic gene expression in serum adiponectin concentrations in mice.

Several humoral factors, such as adiponectin and urate, have been suggested to affect metabolic syndromes. Previously, we reported a reduction in blood adiponectin concentrations after a high-fructose diet partially via the vagus nerve in rats. Although a lithogenic diet (LD), i.e., supplementation of a normal control diet (CT) with 0.6% cholesterol and 0.2% sodium cholate, reduced blood adiponectin concentrations, the involvement of the vagus nerve in this mechanism remains unclear. To estimate the involvement of the vagus nerve in the regulation of blood adiponectin concentrations using an LD, male imprinting control region mice that had been vagotomized (HVx) or only laparotomized (Sham) were administered a CT or an LD for 10 weeks. Serum adiponectin concentrations in the Sham-LD, HVx-CT, and HVx-LD groups were reduced by half compared with the Sham-CT group. The hepatic mRNA levels of fibroblast growth factor 21 (Fgf21), which reportedly stimulates adiponectin secretion from white adipose tissue, were lower in the LD groups compared with the CT groups. HepG2 hepatoma cells showed that various bile acids reduced the mRNA expression of FGF21. Moreover, the LD increased serum urate concentrations and reduced hepatic expressions of the acyl-CoA oxidase 1 (Acox1) mRNA and glucokinase, suggesting insufficient regeneration of ATP from AMP. In conclusion, serum adiponectin concentration may be regulated via the vagus nerve in normal mice, whereas a reduction of hepatic Fgf21 mRNA by bile acids may also lower serum adiponectin levels. Moreover, the LD may promote hepatic AMP accumulation and subsequently increase the serum urate concentration in mice.

The Japanese Breast Cancer Society Clinical Practice Guidelines for systemic treatment of breast cancer, 2022 edition.

The Japanese Breast Cancer Society (JBCS) Clinical Practice Guidelines for systemic treatment of breast cancer were updated to the 2022 edition through a process started in 2018. The updated guidelines consist of 12 background questions (BQs), 33 clinical questions (CQs), and 20 future research questions (FRQs). Multiple outcomes including efficacy and safety were selected in each CQ, and then quantitative and qualitative systematic reviews were conducted to determine the strength of evidence and strength of recommendation, which was finally determined through a voting process among designated committee members. Here, we describe eight selected CQs as important updates from the previous guidelines, including novel practice-changing updates, and recommendations based on evidence that has emerged specifically from Japanese clinical trials.

Correction to: Vitiligo and tumor response in a patient with amelanotic melanoma undergoing nivolumab treatment.

[This corrects the article DOI: 10.1007/s13691-021-00515-w.].

Vitiligo and tumor response in a patient with amelanotic melanoma undergoing nivolumab treatment.

Vitiligo, an acquired depigmenting disorder of the skin that reacts against normal melanocytes, sometimes occurs as an immune-related adverse event in the treatment of melanoma with immune checkpoint inhibitors. It has been known that the occurrence of vitiligo is associated with a favorable therapeutic response in patients with melanoma, but it is not yet clear whether the association also applies to amelanotic melanoma, a minor subtype of melanoma with little or no melanin pigmentation. We report a patient with amelanotic melanoma of the esophagus who responded well to nivolumab treatment. Shortly after the tumor response, vitiligo was found on the patient's forearms. This case suggests that the occurrence of vitiligo is associated with a favorable response to nivolumab treatment for amelanotic melanoma.

Platelet isoform of phosphofructokinase accelerates malignant features in breast cancer.

The platelet isoform of phosphofructokinase (PFKP) is one of the key enzymes in the glycolytic pathway. PFKP is highly expressed in several cancers, and it has been reported to be involved in the progression of cancer cells. However, its oncological role in breast cancer (BC) remains unclear. The present study aimed to evaluate the function of PFKP in BC cells and its expression level in patients with BC. Firstly, the mRNA and protein expression of PFKP was evaluated in BC and non­cancerous mammary cell lines. Polymerase chain reaction (PCR) array analysis was conducted to evaluate the correlation between PFKP and 84 cancer­related genes. Then, PFKP knockdown was conducted using small interfering RNA, and cell proliferation, invasiveness and migration were analyzed. Furthermore, the association between PFKP mRNA expression and clinicopathological factors was investigated in 167 patients with BC. PFKP was highly expressed in estrogen receptor­negative and human epidermal growth factor receptor 2­negative BC cell lines. PCR array analysis demonstrated that the expression level of PFKP was significantly correlated with that of transforming growth factor­ß1 and MYC proto­oncogene. PFKP knockdown significantly decreased the proliferation and invasiveness of MCF7, SK­BR­3, and MDA­MB­231 cells. Furthermore, cell migration was inhibited in SK­BR­3 and MDA­MB­231 cells. In the clinical specimens, patients with T2/T3/T4, lymph node metastasis, or stage II/III/IV exhibited higher expression of PFKP mRNA than patients with less severe disease. In conclusion, the present findings indicated that PFKP is involved in promoting tumor­progressive oncological roles in BC cells across different subtypes and is considered a possible novel therapeutic target for BC.

Drug-induced thrombocytopenia associated with trastuzumab in a patient with HER2-positive recurrent gastric cancer.

Here, we report a 57-year-old female patient with HER2-positive recurrent gastric cancer who experienced drug-induced thrombocytopenia associated with trastuzumab, a humanized anti-HER2 monoclonal antibody. Shortly after the initiation of S-1, oxaliplatin, and trastuzumab chemotherapy, the patient experienced severe thrombocytopenia and did not respond to platelet transfusions. Based on the findings of increased numbers of polynuclear megakaryocytes in the bone marrow and an elevated level of platelet-associated IgG (PA-IgG), the patient was diagnosed with drug-induced thrombocytopenia (DITP). The platelet count recovered rapidly with oral prednisolone (1 mg/kg). Since we initially suspected oxaliplatin as the causal agent, S-1 was restarted as a monotherapy, followed by trastuzumab after a 3-week interval, without oxaliplatin. On the second day after the addition of trastuzumab, severe thrombocytopenia occurred again, which suggests that trastuzumab was responsible for the DITP. The patient no longer experienced severe thrombocytopenia during the subsequent S-1 and oxaliplatin chemotherapy, which supports this hypothesis.

High Protein Diet Feeding Aggravates Hyperaminoacidemia in Mice Deficient in Proglucagon-Derived Peptides.

(1) Background: Protein stimulates the secretion of glucagon (GCG), which can affect glucose metabolism. This study aimed to analyze the metabolic effect of a high-protein diet (HPD) in the presence or absence of proglucagon-derived peptides, including GCG and GLP-1. (2) Methods: The response to HPD feeding for 7 days was analyzed in mice deficient in proglucagon-derived peptides (GCGKO). (3) Results: In both control and GCGKO mice, food intake and body weight decreased with HPD and intestinal expression of Pepck increased. HPD also decreased plasma FGF21 levels, regardless of the presence of proglucagon-derived peptides. In control mice, HPD increased the hepatic expression of enzymes involved in amino acid metabolism without the elevation of plasma amino acid levels, except branched-chain amino acids. On the other hand, HPD-induced changes in the hepatic gene expression were attenuated in GCGKO mice, resulting in marked hyperaminoacidemia with lower blood glucose levels; the plasma concentration of glutamine exceeded that of glucose in HPD-fed GCGKO mice. (4) Conclusions: Increased plasma amino acid levels are a common feature in animal models with blocked GCG activity, and our results underscore that GCG plays essential roles in the homeostasis of amino acid metabolism in response to altered protein intake.

Production of starch with antioxidative activity by baking starch with organic acids.

A starch ingredient with antioxidative activity, as measured by the DPPH method, was produced by baking corn starch with an organic acid; it has been named ANOX sugar (antioxidative sugar). The baking temperature and time were fixed at 170 °C and 60 min, and the organic acid used was selected from preliminary trials of various kinds of acid. The phytic acid ANOX sugar preparation showed the highest antioxidative activity, but the color of the preparation was almost black; we therefore selected L-tartaric acid which had the second highest antioxidative activity. The antioxidative activity of the L-tartaric acid ANOX sugar preparation was stable against temperature, light, and enzyme treatments (α-amylase and glucoamylase). However, the activity was not stable against variations in water content and pH value. The antioxidative activity of ANOX sugar was stabilized by treating with boiled water or nitrogen gas, or by pH adjustment.

Synaptotagmin 13 Is Highly Expressed in Estrogen Receptor-Positive Breast Cancer.

BACKGROUND: Accumulating evidence indicates tumor-promoting roles of synaptotagmin 13 (SYT13) in several cancers; however, no studies have investigated its expression in breast cancer (BC). This study aimed to clarify the significance of SYT13 in BC. METHODS: SYT13 mRNA expression levels were evaluated in BC cell lines. Polymerase chain reaction (PCR) array analysis was conducted to determine the correlation between expression levels of SYT13 and other tumor-associated genes. Then, the association of SYT13 expression levels in the clinical BC specimens with patients' clinicopathological factors was evaluated. These findings were subsequently validated using The Cancer Genome Atlas (TCGA) database. RESULTS: Among 13 BC cell lines, estrogen receptor (ER)-positive cells showed higher SYT13 mRNA levels than ER-negative cells. PCR array analysis revealed positive correlations between SYT13 and several oncogenes predominantly expressed in ER-positive BC, such as estrogen receptor 1, AKT serine/threonine kinase 1, and cyclin-dependent kinases 4. In 165 patients, ER-positive specimens exhibited higher SYT13 mRNA expression levels than ER-negative specimens. The TCGA database analysis confirmed that patients with ER-positive BC expressed higher SYT13 levels than ER-negative patients. CONCLUSION: This study suggests that SYT13 is highly expressed in ER-positive BC cells and clinical specimens, and there is a positive association of SYT13 with the ER signaling pathways.

Bile acids induced hepatic lipid accumulation in mice by inhibiting mRNA expression of patatin-like phospholipase domain containing 3 and microsomal triglyceride transfer protein.

Preliminary studies have shown that a lithogenic diet (LG), which contains cholesterol and cholic acid, induces gallstones and hepatic lipid accumulation (HLA), and reduction of blood triglyceride in mice. We hypothesized that an LG induces HLA by diminishing hepatic triglyceride excretion; however, there is no clear understanding of the mechanism of LG-induced HLA. This study aimed to investigate transcript expression related to the synthesis, expenditure, and efflux of hepatic triglyceride, in mice fed an LG for 4 weeks. Results showed lower plasma concentrations of triglyceride in the LG group than in the control group, but no symptoms of hepatic injury were observed. Hepatic mRNA expressions of patatin-like phospholipase domain containing 3 (Pnpla3), microsomal triglyceride transfer protein (Mttp), and acyl-CoA oxidase 1 (Acox1) were also reduced in the LG group. Deoxycholic acid and lithocholic acid promoted intracellular lipid accumulation, reduced triglyceride concentration in media, and suppressed expression of PNPLA3 and MTTP in HepG2 human hepatoma cells. These findings suggest that deoxycholic acid and lithocholic acid promote HLA by inhibiting the expression of PNPLA3, ACOX1, and MTTP that are involved in lipid metabolism.

Consumption of lycopene-rich tomatoes improved glucose homeostasis in rats via an increase in leptin levels.

The lycopene content of tomatoes is important because of its effects on vital physiological functions such as improvement of glucose tolerance and non-alcoholic fatty liver disease. To investigate the influence of the lycopene content of tomatoes on glucose tolerance and hepatic lipid content, homogenates of lycopene-rich (LR) or lycopene-free negative control (NC) tomato varieties were administrated to normal rats for 4 weeks. At the end of the experiment, an oral glucose tolerance test (OGTT) was performed. Rats were fed once and then dissected. According to the OGTT results, plasma glucose levels in the LR group were 10% and 9% lower at 15 min and 30 min, respectively, than those in the NC group, whereas plasma insulin levels did not differ between the groups at either time point. Upon dissection, plasma leptin levels in the LR group were higher than those in the NC group, while plasma adiponectin levels did not differ between groups. With the exception of retinol palmitate, no carotenoids were detected in the liver by HPLC analysis. Hepatic retinol palmitate levels and hepatic triacyl glyceride levels did not differ between the groups. We concluded that in normal rats, a lycopene-rich tomato variety improved glucose tolerance via an increase in plasma leptin levels that enhanced insulin sensitivity but did not affect carotenoid accumulation or lipid metabolism.

MZB1 expression indicates poor prognosis in estrogen receptor-positive breast cancer.

Breast cancer (BC) is the most common malignant tumor in females. Development of novel biomarkers or therapeutic targets may contribute toward the improvement of a patient's prognosis. Marginal zone B and B1 cell-specific protein (MZB1) is an unfolded protein response-related chaperone and mainly exists in the endoplasmic reticulum of B lymphocytes, although little is known regarding its role in BC cells. The present study aimed to investigate the significance of MZB1 expression in BC. To begin with, MZB1 mRNA expression levels in 13 BC cell lines and two non-cancerous mammary cell lines were evaluated. Next, mRNA and protein expression of MZB1 in BC patient tumor specimens was evaluated to assess the association between expression and clinicopathological factors or prognosis. MZB1 mRNA expression levels were detectable in four estrogen receptor (ER)-positive BC cell lines. When ratios of MZB1 mRNA expression levels between BC and non-cancerous specimens were evaluated, patients with stage III disease exhibited a higher ratio than patients with stage 0/I/II disease (P=0.009). Using immunohistochemistry, patients with ER-positive BC more frequently expressed MZB1, compared with patients with ER-negative BC (P=0.003). In patients with ER-positive BC, patients with MZB1-positive BC experienced shorter disease-free survival (DFS) times than patients with negative BC (P=0.026). Multivariate analysis of DFS demonstrated that MZB1 positivity was an independent prognostic factor (P=0.022). The results of the present study suggested that MZB1 expression may be associated with a more advanced stage of BC. Furthermore, in patients with ER-positive BC, MZB1 may be a potential prognostic marker.

Chemotherapy for biliary tract cancer: real-world experience in a single institute.

The standard chemotherapy regimen for unresectable or recurrent biliary tract cancer is gemcitabine combined with cisplatin (GC). To evaluate the effectiveness and safety of chemotherapy in patients with unresectable or recurrent biliary tract cancer in the real world, we retrospectively analyzed the clinical courses of patients who underwent chemotherapy with GC from January 2015 to November 2019. Forty-eight patients underwent the GC regimen. One patient (2.1%) achieved a complete response, seven patients (14.6%) achieved a partial response, 26 patients (54.2) achieved stable disease, 11 patients (22.9%) achieved progressive disease, and 3 patients (6.3%) were not evaluable. The overall response rate was 16.7%. The median overall survival was 14.2 months (95% CI: 13.8-14.6), and the median progression-free survival was 7.7 months (95% CI: 4.2-11.2). Thirty-nine patients (81.3%) experienced grade 3 or higher severe adverse events as follows: 54.2% experienced neutropenia, 20.8% experienced anemia, 12.5% experienced thrombocytopenia and 20.8% experienced biliary tract infection. As a second-line chemotherapy, S-1 was used in seventeen patients, and stable disease was achieved in three patients (17.6%). The GC regimen for biliary tract cancer is effective and safe for unresectable or recurrent biliary tract cancer in routine clinical practice.

Nippostrongylus brasiliensis: increase of sialomucins reacting with anti-mucin monoclonal antibody HCM31 in rat small intestinal mucosa with primary infection and reinfection.

Infections with the parasitic helminth, Nippostrongylus brasiliensis, cause changes in rat small intestinal goblet cell mucin, particularly in the peripheral sugar residues of oligosaccharide. These changes may correlate with expulsion. In this study, we examined changes in mucin oligosaccharides caused by primary infection and reinfection with N. brasiliensis, using two monoclonal antibodies, HCM31 and PGM34, that react with sialomucin and sulfomucin, respectively. Enzyme-linked immunosorbent assay of jejunal mucins showed that the relative reactivity of mucins with HCM31, but not PGM34, increased up to 16 days after primary infection and 6 days after reinfection, the times when the worms were expelled from the rats. Immunohistochemical studies confirmed that goblet cells stained with HCM31 greatly increased at the time of worm expulsion. These results indicate that the marked increase observed in HCM31-reactive sialomucins may be related to expulsion of the worms.

Effect of 12-Week Daily Intake of the High-Lycopene Tomato (Solanum Lycopersicum), A Variety Named "PR-7", on Lipid Metabolism: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study.

Tomato (Solanum lycopersicum) is a rich source of lycopene, a carotenoid that confers various positive biological effects such as improved lipid metabolism. Here, we conducted a randomized, double-blind, placebo-controlled, parallel-group comparative study to investigate the effects of regular and continuous intake of a new high-lycopene tomato, a variety named PR-7, for 12 weeks, based on 74 healthy Japanese subjects with low-density lipoprotein cholesterol (LDL-C) levels ≥120 to <160 mg/dL. The subjects were randomly assigned to either the high-lycopene tomato or placebo (lycopene-free tomato) group. Each subject in the high-lycopene group ingested 50 g of semidried PR-7 (lycopene, 22.0-27.8 mg/day) each day for 12 weeks, while subjects in the placebo group ingested placebo semidried tomato. Medical interviews were conducted, vital signs were monitored, body composition was determined, and blood and saliva samples were taken at weeks 0 (baseline), 4, 8, and 12. The primary outcome assessed was LDL-C. The intake of high-lycopene tomato increased lycopene levels in this group compared to levels in the placebo group (p < 0.001). In addition, high-lycopene tomato intake improved LDL-C (p = 0.027). The intake of high-lycopene tomato, PR-7, reduced LDL-C and was confirmed to be safe.

Impact of Patient Age and Histological Type on Radioactive Iodine Avidity of Recurrent Lesions of Differentiated Thyroid Carcinoma.

BACKGROUND: Age is a prognostic factor for recurrent differentiated thyroid carcinoma (DTC) and may be related to radioactive iodine (RAI) nonavidity. Indications for molecular-targeted drugs (MTDs) are currently limited to RAI-refractory DTC. Demonstrating refractoriness to RAI, mainly indicated by RAI nonavidity, may be a barrier to the introduction of MTDs for elderly patients. The present study was conducted to evaluate the impact of age and histological type on the RAI avidity of recurrent lesions of DTC. METHODS: Two hundred fifty-eight patients (189 patients with classic papillary thyroid carcinoma [cPTC], 8 patients with follicular variant of papillary thyroid carcinoma, and 61 patients with follicular thyroid carcinoma), who underwent their first RAI whole-body scanning for recurrent DTC at our institution between 2004 and 2013, were retrospectively studied. Radioactive iodine uptake was determined by visible uptake by metastatic lesion(s) in a diagnostic RAI-whole-body scan. RESULTS: The prevalence of RAI-avid lung metastases in cPTC indicated a significant, inverse correlation with age (<55 years, 36.2%; ≥55 years, 3%; P < 0.001). By contrast, for follicular thyroid carcinoma, the prevalence of RAI avidity was not influenced by age. Similar tendencies were observed for lymph node metastases. CONCLUSIONS: Radioactive iodine avidity by metastatic lesions of cPTC in elderly patients, especially those older than 55 years, was seldom demonstrated. Adherence to a strategy of restricting MTD administration after confirmation of RAI refractoriness should be revisited for elderly patients. A strategy of omitting RAI treatment should be taken into account when considering age and histological type.