Stepped wedge cluster randomized trials (SW-CRT) is a kind of cluster randomized controlled trial mainly applied in the field of public health policy that has emerged in recent years, which has gradually attracted the attention of workers in the field of health and wellness. At present, this trial method is not widely used at home and abroad, and there are various ways of sample size calculation and statistical analysis. This paper describes the principles, categories, and differences between SW-CRT and traditional randomized controlled trials, and outlines sample size calculation and statistical analysis methods. In general, SW-CRT is characterized by clustering, cross-design, and measurement of results at multiple time points. In terms of sample size calculation, it is necessary to distinguish between clusters with the same and different sizes, and commonly used sample size calculation procedures can be implemented in Stata, R, and SAS software, as well as in fixed online websites, including the "Steppedwedge" program, the "swCRTdesign" program, the "Swdpwr" program, the "CRTpowerdist" program, and the "Shiny CRT Calculator" tool and so on. Based on the design characteristics of SW-CRT, the researcher should also consider the confounding factors of time effects and repeated measurements of result. Therefore, the statistical analysis methods are often based on generalized linear mixed model (GLMM) and generalized estimating equations (GEE). However, most of the above models have been proposed based on cross-sectional studies, there is a lack of statistical methods for queue design and SW-CRT with transitional period now, and more comprehensive methodological exploration is still needed in the future.
ObjectiveTo detect the expressions of p27Kip1, RalA, and SPOCK1 in the cancer tissues of the elderly patients with colorectal cancer (CRC) and explore the relations between their expressions and clinical pathological characteristics as well as prognosis. MethodsThe clinicopathologic data of elderly CRC patients treated and underwent surgical resection in the Kailuan General Hospital Linxi Hospital from May 2019 to May 2022 were retrospectively collected. The immunohistochemistry was used to detect the expressions of p27Kip1, RalA, and SPOCK1 proteins in the CRC tissues and the corresponding adjacent tissues. The Kaplan-Meier method was applied to analyze the survival of CRC patients with p27Kip1, RalA, and SPOCK1 positive and negative expressions. The multivariate Cox proportional hazards regression model was applied to analyze the influencing factors of prognosis in the patients with CRC. The test level was set as α=0.05. ResultsA total of 149 elderly CRC patients were enrolled. All patients were followed up for 2 years, and 45(30.2%) cases died during the follow-up period. The positive rate of p27Kip1 protein expression in the CRC tissues was lower than that in the corresponding adjacent tissues (P<0.05), while the positive rates of RalA and SPOCK1 protein expressions were higher than those in the corresponding adjacent tissues (P<0.05). The proportions of mucinous carcinoma, TNM stages Ⅲ–Ⅳ, low differentiation, lymph node metastasis, and T staging T2–T4 in the patients with negative p27Kip1 and positive RalA and SPOCK1 expressions were higher than those in the patients with positive p27Kip1 and negative RalA and SPOCK1 expressions (P<0.05). The proportions of patients with TNM stages Ⅲ–Ⅳ, negative p27Kip1 and positive RalA and SPOCK1 expressions in the death patients were higher than those in the survival patients (P<0.05). The survival curves plotted by the Kaplan-Meier method showed that the survival curves of patients with positive expression of p27Kip1 and negative expression of RalA and SPOCK1 in the cancer tissues were significantly better than those with positive expression of p27Kip1 and negative expression of RalA and SPOCK1 (respectively: log-rank χ2=11.678, P=0.001; log-rank χ2=10.836, P=0.001; log-rank χ2=10.792, P=0.001). The multivariate Cox proportional hazards regression model analysis revealed that the negative expression of p27Kip1 [HR (95%CI)=2.807 (1.490, 5.287), P=0.001], positive expressions of RalA and SPOCK1 [HR (95%CI)=2.769 (1.493, 5.134), P=0.001; HR (95%CI)=3.075 (1.610, 5.871), P=0.001] were the risk factors for postoperative mortality in the CRC patients. ConclusionsThe results of this study suggest that the positive rate of p27Kip1 protein expression is low in the cancer tissues of elderly CRC patients, while the positive rates of RalA and SPOCK1 proteins are high. In addition, the negative expression of p27Kip1 protein and the positive expression of RalA and SPOCK1 proteins in elderly CRC tissues are associated with clinical characteristics such as poor tissue type, late TNM staging, and low degree of differentiation. Moreover, the negative expression of p27Kip1 and the positive expressions of RalA and SPOCK1 are unfavorable for prognosis of elderly CRC patients.
