Risk for Thyroid Cancer Recurrence Is Higher in Men Than in Women Independent of Disease Stage at Presentation.

Background: Well-differentiated thyroid cancer (DTC) presents at a more advanced stage in men than in women, and the mortality in men is higher than that in women. However, it is not clear whether DTC recurrence is affected by sex independent of stage at presentation. The objective of the present study was to assess if male sex is an independent risk factor for recurrence of DTC. Methods: The Canadian Collaborative Network for Cancer of the Thyroid (CANNECT) is a collaborative registry to describe patterns of care for thyroid cancer. We included patients from the CANNECT registry with DTC diagnosed at age 18 or older between 2000 and 2010. We compared men and women with respect to presentation, management, and recurrence risk, stratified for American Joint Committee on Cancer (AJCC) stage. Results: We included 2595 patients, 2067 (79.7%) women and 528 (20.3%) men. Men presented with more advanced AJCC stage (p < 0.001), T stage (p < 0.001), N stage (p < 0.001), and M stage (p = 0.002) There was no difference in follow-up duration between women (7.7 ± 4.0 [mean ± standard deviation] years) and men (7.7 ± 4.0 years, p = 0.985). Overall recurrence was 2.2% (n = 46) for women and 8.5% (n = 45) for men (p < 0.001). In multivariate analysis adjusted for AJCC stage, men were at significantly greater risk for DTC recurrence than women (adjusted hazard ratio 2.72 [95% confidence interval [CI] 1.78-4.20]; p < 0.001). In multivariate analysis adjusted for tumor-node-metastasis (TNM) stage, men were at significantly greater risk for DTC recurrence than women (adjusted hazard ratio 2.31 [CI 1.48-3.60]; p < 0.001). Conclusions: Our study confirms that the risk for recurrence of DTC is higher in men than in women. Although men tend to present with more advanced-stage disease, the difference in recurrence risk persists when adjusted for stage of presentation. It needs to be determined whether sex should influence follow-up intensity and/or duration.

Regional Variation across Canadian Centers in Radioiodine Administration for Thyroid Remnant Ablation in Well-Differentiated Thyroid Cancer Diagnosed in 2000-2010.

Background. Use of radioactive iodine (RAI) ablation has been reported to vary significantly between studies. We explored variation in RAI ablation care patterns between seven thyroid cancer treatment centers in Canada. Methods. The Canadian Collaborative Network for Cancer of the Thyroid (CANNECT) is a collaborative registry to describe and analyze patterns of care for thyroid cancer. We analyzed data from seven participating centers on RAI ablation in patients diagnosed with well-differentiated (papillary and follicular) thyroid cancer between 2000 and 2010. We compared RAI ablation protocols including indications (based on TNM staging), preparation protocols, and administered dose. We excluded patients with known distant metastases at time of RAI ablation. Results. We included 3072 patients. There were no significant differences in TNM stage over time. RAI use increased in earlier years and then declined. The fraction of patients receiving RAI varied significantly between centers, ranging between 20-85% for T1, 44-100% for T2, 58-100% for T3, and 59-100% for T4. There were significant differences in the RAI doses between centers. Finally, there was major variation in the use of thyroid hormone withdrawal or rhTSH for preparation of RAI ablation. Conclusion. Our study identified significant variation in use of RAI for ablation in patients with well-differentiated thyroid cancer both between Canadian centers and over time.

Phononic crystals based on LiNbO3 realized using domain inversion by electron-beam irradiation.

We report in this paper about the realization of domain inversion in z-cut lithium niobate by electron beam irradiation in order to perform phononic crystals. The fabrication of these phononic crystals on z-cut LiNbO3, which is, in our case, a periodic repetition of voids and LiNbO3, was achieved by domain inversion followed by wet etching, taking advantage of the large difference in etching rate between z+ and z- faces. A pertinent choice of irradiation conditions such as accelerating voltage, beam current, and charge density was determined and optimized. Two-dimensional structures at the micrometer scale were then realized on z-cut LiNbO3. We demonstrate the achievement of hexagons with diameters between 2 microm and 18 microm, with a very important depth close to 30 microm, which depends on the etching time and the hole size. The obtained structures, which exhibit a filling fraction varying from 1% to 64%, were characterized before etching by polarizing microscope to visualize the inverted domains. After HF etching, scanning electron microscopy was used to observe the obtained phononic structures. Taking into account the obtained filling fraction values and the size of created hexagons, the frequency band gap of these structures is expected at a range of 200 to 350 MHz. As expected in this frequency range, we have proven experimentally the existence of the phononic band gap on z-cut LiNbO3 by combination of a realized phononic crystal with a surface acoustic wave (SAW) device.

Effect of diamond nucleation process on propagation losses of AlN/diamond SAW filter.

In this work, the effect of a diamond nucleation process on freestanding aluminium nitride (AlN)/diamond surface acoustic wave (SAW) device performances was studied. Before diamond deposition, silicon (Si) substrates have been mechanically nucleated, using an ultrasonic vibration table with submicron diamond slurry, and bias-enhanced nucleated (BEN). Freestanding diamond layers obtained on mechanically scratched Si substrates exhibit a surface roughness of R(MS) = 13 nm, whereas very low surface roughness (as low as R(MS) < or = 1 nm) can be achieved on a freestanding BEN diamond layer. Propagation losses have been measured as a function of the operating frequency for the two nucleation techniques. Dispersion curves of phase velocities and electromechanical coupling coefficient (K2) were determined experimentally and by calculation as a function of normalized thickness AlN film (kh(AlN) = 2pi h(AlN)/lambda). Experimental results show that the propagation losses strongly depend on the nucleation technique, and that these losses are weakly increased with frequency when the BEN technique is used.