Differential clinical outcomes after 3 versus 5 years in a comparison of preoperative chemotherapy with and without radiotherapy in locally advanced rectal cancer: A national cohort propensity score-matched study.

Background: Preoperative chemotherapy alone might be a good alternative to preoperative chemoradiotherapy for patients with locally advanced rectal cancer, yet long-term real-world data from the same cohort are lacking. Methods: Patients diagnosed with stage II-III rectal adenocarcinoma from 2011 to 2015 were randomly sampled from the SEER-Plus database to evaluate the superiority of preoperative chemoradiotherapy versus preoperative chemotherapy alone. Findings: A total of 1314 eligible patients were enrolled, with a median follow-up of 74.0 months. At 3-year follow-up, neither overall survival (OS) nor cancer-specific survival (CSS) was significantly different between the two treatment groups. At 5-year follow-up, CSS was similar across groups (HR 0.768, 95% CI 0.532-1.108; P = 0.156), but the 5-year OS was significantly better in the preoperative chemoradiotherapy group than in the preoperative chemotherapy group (HR 0.682, 95% CI 0.538-0.866; P = 0.002). Besides, the landmark analysis indicated a direct contrast in the CSS within 3 years (HR 1.101, 95% CI 0.598-2.029; P = 0.756) versus that at 3-5 years (HR 0.597, 95% CI 0.377-0.948; P = 0.027). The landmark analysis also showed directly contrasting OS outcomes within 3 years (HR 0.761, 95% CI 0.533-1.086; P = 0.130) versus those at 3-5 years (HR 0.621, 95% CI 0.451-0.857; P = 0.003). Interpretation: In patients with locally advanced rectal cancer under real-world treatment practices, the addition of preoperative radiotherapy to chemotherapy improves survival outcomes at 3-5 years' follow-up but not at 3-year follow-up.

Optimizing fluidity and tensile strength of magnetically driven epoxy-cement repair materials based on response surface.

Underwater crack repair is challenging due to drainage and exhaust, slurry retention at fixed points, and other issues. Magnetically driven epoxy resin cement slurry was developed, which can perform directional movement and fixed-point retention of slurry under the effect of an applied magnetic field. This paper focuses on slurry fluidity and tensile properties. Firstly, in the preliminary pre-study, the main influencing factors of the ratios were determined. Then, the optimum range of each factor is determined by a single-factor experiment. Furthermore, the response surface method (RSM) is applied to obtain an optimal ratio. Finally, the slurry is characterized by micro. Results showed that the evaluation index F proposed in this paper can well evaluate the interaction between fluidity (X) and tensile strength (Y). The 2FI regression model and the quadratic regression model are developed with fluidity and tensile strength as the response values and Epoxy Resin (ER) content, water-cement ratio, Fe3O4 content and sulphoaluminate cement (SAC) content as the influencing factors, and have reasonable fit and reliability. The relationship between the degree of influence of the influencing factors on the response value X and the response value Y in ascending order was: ER content > water-cement ratio > SAC content > Fe3O4 content. The magnetically driven slurry made by the optimal ratio can reach a fluidity rate of 223.31 mm and a tensile strength of 2.47 MPa. This is with relative errors of 0.36% and 1.65% from the model predicted values. Microscopic analysis showed that the magnetically driven epoxy resin cement slurry had a favorable crystalline phase, surface morphology, and structural composition.