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- Bonjer, H. Jacob, et al.
(författare)
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Laparoscopically assisted vs open colectomy for colon cancer : a meta-analysis
- 2007
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Ingår i: Archives of surgery (Chicago. 1960). - 0004-0010 .- 1538-3644. ; 142:3, s. 298-303
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Forskningsöversikt (refereegranskat)abstract
- OBJECTIVE: To perform a meta-analysis of trials randomizing patients with colon cancer to laparoscopically assisted or open colectomy to enhance the power in determining whether laparoscopic colectomy for cancer is oncologically safe. DATA SOURCES: The databases of the Barcelona, Clinical Outcomes of Surgical Therapy (COST), Colon Cancer Laparoscopic or Open Resection (COLOR), and Conventional vs Laparoscopic-Assisted Surgery in Patients With Colorectal Cancer (CLASICC) trials were the data sources for the study. STUDY SELECTION: Patients who had at least 3 years of complete follow-up data were selected. DATA EXTRACTION: Patients who had undergone curative surgery before March 1, 2000, were studied. Three-year disease-free survival and overall survival were the primary outcomes of this analysis. DATA SYNTHESIS: Of 1765 patients, 229 were excluded, leaving 796 patients in the laparoscopically assisted arm and 740 patients in the open arm for analysis. Three-year disease-free survival rates in the laparoscopically assisted and open arms were 75.8% and 75.3%, respectively (95% confidence interval [CI] of the difference, -5% to 4%). The associated common hazard ratio (laparoscopically assisted vs open surgery with adjustment for sex, age, and stage) was 0.99 (95% CI, 0.80-1.22; P = .92). The 3-year overall survival rate after laparoscopic surgery was 82.2% and after open surgery was 83.5% (95% CI of the difference, -3% to 5%). The associated hazard ratio was 1.07 (95% CI, 0.83-1.37; P = .61). Disease-free and overall survival rates for stages I, II, and III evaluated separately did not differ between the 2 treatments. CONCLUSION: Laparoscopically assisted colectomy for cancer is oncologically safe.
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| 2. |
- Hieronymus, C. F., et al.
(författare)
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A dynamical model for generating Eurasian lithospheric stress and strain rate fields : Effect of rheology and cratons
- 2008
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 113:B7, s. B07404-
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Tidskriftsartikel (refereegranskat)abstract
- For most continents, stress models driven by plate boundary forces have successfully reproduced the main characteristics of the stress field. However, Eurasia has remained a challenge due to its large areas of intraplate deformation. We present a set of three-dimensional models of the upper mantle lithosphere system for a simplified geometry of the Eurasian plate where we try to match the first-order characteristics of the stress and strain rate fields simultaneously. For typical elastic, viscous, or plastic rheologies, high stress levels are required in order to produce realistic convergence rates between India and Asia. Our models show robustly that such stresses are transmitted throughout most of the plate, dominating locally generated stresses even in distal regions such as Europe in a manner that is not compatible with observations. Cratons with roots that extend deep into the mantle are unable to provide a significant stress-shielding effect unless the viscosity contrast between the asthenosphere and the underlying mantle is around 100 or greater. A damage rheology for the lithosphere with history-dependent behavior and material softening by a viscosity reduction of several orders of magnitude is shown to eliminate this conundrum. Continental convergence at high velocity but low stress is facilitated by the formation of long-lived shear zones similar to those observed north of the Himalayas. The low stress associated with the collision, together with the decoupling effect of the shear zones, causes the distal stress field in Europe to be controlled by the effects of the neighboring boundaries in agreement with observations.
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