Hemithyroidectomy versus total thyroidectomy for well differentiated T1-2 N0 thyroid cancer: systematic review and meta-analysis.

BACKGROUND: Evidence for limiting the extent of surgery in patients with low-risk thyroid cancer is lacking. METHODS: A systematic search was performed according to the PRISMA and MOOSE guidelines to assess the effect of total thyroidectomy (TT) with or without radioactive iodine (RAI) treatment versus hemithyroidectomy (HT) on recurrence and overall mortality in patients with differentiated (papillary or follicular) T1-2 N0 thyroid cancer. PubMed, Embase and Cochrane databases were searched, and two authors independently assessed the articles. RESULTS: A total of ten eligible articles were identified. All were observational cohort series, representing a total of 23 134 patients, of which 17 699 were available for meta-analysis. Six studies included patients who had TT followed by RAI treatment. The pooled recurrence rate after TT ± RAI and HT was 2·3 and 2·8 per cent respectively (odds ratio (OR) 1·12, 95 per cent c.i. 0·82 to 1·53; P = 0·48). The pooled 20-year overall survival rate after TT ± RAI was 96·8 per cent, compared with 97·4 per cent for HT (OR 1·30, 0·71 to 2·37; P = 0·40). Overall, higher complication rates were found in the TT ± RAI group. CONCLUSION: Recurrence rates after HT for treatment of well differentiated T1-2 N0 thyroid cancer were similar to those after TT ± RAI, with a lower incidence of treatment-related complications.

ANTECEDENTES: No hay evidencia para limitar la extensión de la cirugía en pacientes con cáncer de tiroides de bajo riesgo. MÉTODOS: Se realizó una búsqueda sistemática siguiendo las recomendaciones PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) y MOOSE (Meta-analysis of Observational Studies in Epidemiology) para evaluar el efecto de la tiroidectomía total (TT) +/− yodo radioactivo (radioactive iodine treatment, RAI) versus hemitiroidectomía (HT) en la recidiva y en la mortalidad global en el cáncer de tiroides diferenciado (papilar/folicular) T1-T2N0. Se realizaron búsquedas en las bases de datos PubMed, Embase y Cochrane, y dos autores evaluaron los artículos de forma independiente. RESULTADOS: Se identificaron un total de 10 artículos de interés. Todos ellos eran estudios de cohortes observacionales, con un total de 23.134 pacientes, de los cuales 17.699 se incluyeron en el metaanálisis. En seis estudios, los pacientes fueron tratados mediante TT seguida de RAI. Las tasas agrupadas de recidiva tras TT +/− RAI y HT fueron 2,3% and 2,8%, respectivamente (razón de oportunidades, odds ratio, OR = 1,12, i.c. del 95% 0,82-1,54, P = 0.48). La supervivencia global a 20 años de TT +/− RAI fue del 96,8% en comparación con el 97,4% para la HT (OR = 1,30, i.c. del 95% 0,71-2,37, P = 0,40). Globalmente, se observaron más complicaciones en el grupo de TT +/− RAI. CONCLUSIÓN: Esta revisión sistemática con metaanálisis demuestra tasas de recidiva similares tras una HT para el tratamiento del cáncer de tiroides T1-2N0 bien diferenciado en comparación con TT +/− RAI, con una menor incidencia de complicaciones relacionadas con el tratamiento.

Internet programs targeting multiple lifestyle interventions in primary and secondary care are not superior to usual care alone in improving cardiovascular risk profile: a systematic review.

OBJECTIVE: To review the effects of Internet delivered multiple modifiable lifestyle interventions complementary to usual care on cardiovascular risk factors in the primary and secondary healthcare setting. METHOD: PubMed, EMBASE.com, CINAHL, PsycINFO, and the Cochrane Library were searched up to June 2012 for English written studies that 1) addressed multiple lifestyle interventions, 2) used Internet intervention through websites or email, 3) included at least one usual care group not using Internet, 4) aimed to improve any of cardiovascular risk factors and 5) targeted patients aged 18 or older. RESULTS: Our systematic search yielded 1857 citations of which 9 were selected for this review. Three studies reported significant differences in weight loss in favor of the intervention group and five studies reported non-significant differences between groups. From the 7 studies reporting on blood pressure (BP) measurements, two found significant improvement in favor of the intervention group, while the other studies found no significant differences. Only one study found a significant improvement of LDL-C in the intervention group compared to usual care. Another study found a significant improvement of HDL-C in the usual care group compared to the intervention group. CONCLUSION: The addition of a multiple modifiable lifestyle Internet intervention in primary or secondary care is not superior to usual care with respect to prevention and treatment of cardiovascular risk factors. However, an Internet delivered program does have the potential of being successful in reducing the number of doctor's visits and may therefore be cost-effective when applied in large scale.

Texture and shape of two-dimensional domains of nematic liquid crystals.

We present a generalized approach to compute the shape and internal structure of two-dimensional nematic domains. By using conformal mappings, we are able to compute the director field for a given domain shape that we choose from a rich class, which includes drops with large and small aspect ratios and sharp domain tips as well as smooth ones. Results are assembled in a phase diagram that for given domain size, surface tension, anchoring strength, and elastic constant shows the transitions from a homogeneous to a bipolar director field, from circular to elongated droplets, and from sharp to smooth domain tips. We find a previously unaccounted for regime, where the drop is nearly circular, the director field bipolar, and the tip rounded. We also find that bicircular director fields, with foci that lie outside the domain, provide a remarkably accurate description of the optimal director field for a large range of values of the various shape parameters.

Magnetic field effects on tactoids of plate-like colloids.

We investigate the effect of a magnetic field on the shape and director field of nematic droplets in dispersions of sterically stabilized and charge-stabilized colloidal gibbsite platelets with a negative diamagnetic anisotropy. Depending on the magnetic field strength and tactoid size, we observe with polarized light microscopy several interesting structures, with different shapes and director fields both with and without defects. In particular, our findings provide the first experimental evidence for the existence of the split-core defect structure predicted ten years ago by Mkaddem and Gartland [Phys. Rev. E 62, 6694 (2000)]. The split-core structure is a metastable director-field configuration that can be stabilized by a sufficiently strong externally applied magnetic field but only if the diamagnetic anisotropy of the particles is negative. To account for our observations, we present a calculation of the stability regions of different shapes and director-field structures as a function of tactoid size, anchoring conditions, surface tension, elastic constants, and magnetic field strength. By fitting the experimental data to the theoretically predicted structures, we are able to extract values for the splay elastic constant, interfacial tension, and anchoring strength. Remarkably, we find significant differences between the two systems studied: for sterically stabilized gibbsite in bromotoluene the anchoring strength is one order of magnitude larger than that of aqueous gibbsite, with the latter exhibiting weak and the former strong anchoring of the director field to the interface. The splay elastic constants that we obtain are in agreement with earlier experiments, simulations, and theory, while the interfacial tension and anchoring strength are considerably larger than what was found in earlier experiments.

Tactoids of plate-like particles: size, shape, and director field.

We studied, by means of polarized light microscopy, the shape and director field of nematic tactoids as a function of their size in dispersions of colloidal gibbsite platelets in polar and apolar solvents. Because of the homeotropic anchoring of the platelets to the interface, we found large tactoids to be spherical with a radial director field, whereas small tactoids turn out to have an oblate shape and a homogeneous director field, in accordance with theoretical predictions. The transition from a radial to a homogeneous director field seems to proceed via two different routes depending in our case on the solvent. In one route, the what presumably is a hedgehog point defect in the center of the tactoid transforms into a ring defect with a radius that presumably goes to infinity with decreasing drop size. In the other route, the hedgehog defect is displaced from the center to the edge of the tactoid, where it becomes virtual again going to infinity with decreasing drop size. Furthermore, quantitative analysis of the tactoid properties provides us with useful information on the ratio of the splay elastic constant and the anchoring strength and the ratio of the anchoring strength and the surface tension.