RAS/BRAF mutational status in familial non‑medullary thyroid carcinomas: A retrospective study

There are contrasting views on whether familial non‑medullary thyroid carcinomas (FNMTCs) are characterized by aggressive behavior, and limited evidence exists on the prognostic value of BRAF and RAS mutations in these tumors. Thus, in the present study, clinicopathological features were analyzed in 386 non‑medullary thyroid carcinomas (NMTCs), subdivided in 82 familial and 304 sporadic cases. Furthermore, the RAS and BRAF mutational statuses were investigated in a subgroup of 34 FNMTCs to address their clinical and biological significance. The results demonstrated that, compared with sporadic NMTCs, FNMTCs are characterized by significantly higher rates of multicentricity and bilaterality and are more frequently associated with chronic autoimmune thyroiditis. Notably, a statistically significant difference in the rates of multicentricity was observed by subgrouping familial tumors according to the number of relatives involved; those with ≥3 affected relatives were more likely to be multicentric. Furthermore, the FNMTC cohort exhibited higher rates of tumors >4 cm in size with extrathyroidal or lymph node involvement. However, no significant difference was observed. Similarly, no differences were observed with respect to the age of onset or the patient outcome. The mutational profiling exhibited a rate of 58.8% for BRAF V600E mutations in familial tumors, which is at the upper limit of the mutational frequency observed in historical series of sporadic thyroid cancer. A high rate of NRAS mutations (17.6%) was also observed, mostly in the follicular variant histotype. Notably, compared with BRAF/RAS‑wild type FNMTCs, the familial carcinomas bearing BRAF or NRAS mutations exhibited slightly higher rates of bilaterality and multicentricity, in addition to increased frequency of locally advanced stage or lymph node involvement. The present data support the theory that FNMTCs are characterized by clinicopathological features that resemble a more aggressive phenotype and suggest that RAS/BRAF mutational analysis deserves to be further evaluated as a tool for the identification of FNMTCs with a potentially unfavorable prognosis

Treatment of hyperfunctioning thyroid nodules by percutaneous ethanol injection

BACKGROUND: Autonomous thyroid nodules can be treated by a variety of methods. We assessed the efficacy of percutaneous ethanol injection in treating autonomous thyroid nodules. METHODS: 35 patients diagnosed by technetium-99 scanning with hyperfunctioning nodules and suppressed sensitive TSH (sTSH) were given sterile ethanol injections under ultrasound guidance. 29 patients had clinical and biochemical hyperthyroidism. The other 6 had sub-clinical hyperthyroidism with suppressed sTSH levels (<0.24 μIU/ml) and normal thyroid hormone levels. Ethanol injections were performed once every 1–4 weeks. Ethanol injections were stopped when serum T(3), T(4 )and sTSH levels had returned to normal, or else injections could no longer be performed because significant side effects. Patients were followed up at 3, 6 and, in 15 patients, 24 months after the last injection. RESULTS: Average pre-treatment nodule volume [18.2 ± 12.7 ml] decreased to 5.7 ± 4.6 ml at 6 months follow-up [P < 0.001]. All patients had normal thyroid hormone levels at 3 and 6 months follow-up [P < 0.001 relative to baseline]. sTSH levels increased from 0.09 ± 0.02 μIU/ml to 0.65 ± 0.8 μIU/ml at the end of therapy [P < 0.05]. Only 3 patients had persistent sTSH suppression at 6 months post-therapy. T(4 )and sTSH did not change significantly between 6 months and 2 years [P > 0.05]. Ethanol injections were well tolerated by the patients, with only 2 cases of transient dysphonia. CONCLUSION: Our findings indicate that ethanol injection is an alternative to surgery or radioactive iodine in the treatment of autonomous thyroid nodules

Thermal Ablation for Benign Thyroid Nodules: Radiofrequency and Laser

Although ethanol ablation has been successfully used to treat cystic thyroid nodules, this procedure is less effective when the thyroid nodules are solid. Radiofrequency (RF) ablation, a newer procedure used to treat malignant liver tumors, has been valuable in the treatment of benign thyroid nodules regardless of the extent of the solid component. This article reviews the basic physics, techniques, applications, results, and complications of thyroid RF ablation, in comparison to laser ablation

ATM system buffer design under very low cell loss probability constraints

This paper deals with a general method for buffer design in an ATM system in which the target loss probability should be very low (e.g. less than 10-9). This method is based on the application of the Generalized Extreme Value Theory (GEVT) on results arising from simulation runs. This theory allows the estimation of very small probabilities which would not be evaluable with traditional Montecarlo approach. An advantage of 4/5 decades with respect to Montecarlo limits can be obtained utilizing the same sample set. The extension of the theory to the case of distribution functions of discrete random variables is here discussed. The applicability of the method is here demonstrated with reference to known probability distribution functions (Exponential, Normal, Weibull, Iperexponential, Geometric, Bernoulli and Poissonian). Moreover, the GEVT is applied in the cases of classical queueing systems, i.e. M/D/I, Geo/D/1 and MMPP/D/l. Finally, the general criteria for the evaluation of the basic GEVT parameters are discussed

A combined Montecarlo/GEVT extrapolating method for the estimate of buffer length distribution tails

This paper deals with the application of Generalized Extreme Value Theory (GEVT) to the ATM buffer dimensioning. In particular, a general ATM system simulation model has been defined in order to analyze a large variety of buffer behaviours. The performance of the classical GEVT estimate procedure are evaluated in some critical cases by stressing its limits. In order 10 better cope with these cases, a modified version of the GEVT estimate procedure is proposed. Such a procedure is based on the combined utilization of the knowledge obtained from the classical Montecarlo method and the extrapolating form of the GEVT estimator. The obtained results show that this method allows some limitations of the GEVT approach to be overcome and a very good result accuracy can be reached