Talebi Atefeh, Mohammadnejad Afsaneh, Akbari Abolfazl, Pourhoseingholi Mohamad Amin, Doosti Hassan, Moghimi-Dehkordi Bijan, Agah Shahram, Bahardoust Mansour
Colorectal Research Center, Iran University of Medical Center, Tehran, Iran.
Unit of Epidemiology and Biostatistics, Department of Public Health, University of Southern Denmark, Odense, Denmark.
BMC Surg. 2020 Jul 13;20(1):152. doi: 10.1186/s12893-020-00816-6.
Gastric cancer (GC) has been considered as the 5th most common type of cancer and the third leading cause of cancer-associated death worldwide. The aim of this historical cohort study was to evaluate the survival predictors for all patients with GC using the Cox proportional hazards, extended Cox, and gamma-frailty models.
This historical cohort study was performed according to documents of 1695 individuals having GC referred to three medical centers in Iran from 2001 to 2018. First, most significant prognostic risk factors on survival were selected, Cox proportional hazards, extended Cox, gamma-frailty models were applied to evaluate the effects of the risk factors, and then these models were compared with the Akaike information criterion.
The age of patients, body mass index (BMI), tumor size, type of treatment and grade of the tumor increased the hazard rate (HR) of GC patients in both the Cox and frailty models (P < 0.05). Also, the size of the tumor and BMI were considered as time-varying variables in the extended Cox model. Moreover, the frailty model showed that there is at least an unknown factor, genetic or environmental factors, in the model that is not measured (P < 0.05).
Some prognostic factors, including age, tumor size, the grade of the tumor, type of treatment and BMI, were regarded as indispensable predictors in patients of GC. Frailty model revealed that there are unknown or latent factors, genetic and environmental factors, resulting in the biased estimates of the regression coefficients.
胃癌（GC）被认为是全球第5大常见癌症类型，也是癌症相关死亡的第三大主要原因。这项历史性队列研究的目的是使用Cox比例风险模型、扩展Cox模型和伽马脆弱模型评估所有胃癌患者的生存预测因素。
这项历史性队列研究是根据2001年至2018年转诊至伊朗三个医疗中心的1695例胃癌患者的病历进行的。首先，选择对生存影响最显著的预后风险因素，应用Cox比例风险模型、扩展Cox模型和伽马脆弱模型评估这些风险因素的影响，然后将这些模型与赤池信息准则进行比较。
在Cox模型和脆弱模型中，患者年龄、体重指数（BMI）、肿瘤大小、治疗类型和肿瘤分级均增加了胃癌患者的风险率（HR）（P<0.05）。此外，在扩展Cox模型中，肿瘤大小和BMI被视为随时间变化的变量。此外，脆弱模型表明，模型中至少存在一个未测量的未知因素，即遗传或环境因素（P<0.05）。
一些预后因素，包括年龄、肿瘤大小、肿瘤分级、治疗类型和BMI，被视为胃癌患者不可或缺的预测因素。脆弱模型显示存在未知或潜在因素，即遗传和环境因素，导致回归系数的估计存在偏差。
