Baghestani Ahmad Reza, Hajizadeh Ebrahim, Fatemi Seyed Reza
Department of Biostatistics, Tarbiat Modares University, Tehran, Iran.
Tumori. 2010 May-Jun;96(3):433-7. doi: 10.1177/030089161009600309.
The objective of the study was to assess the impact of prognostic factors on survival of patients with gastric cancer in the presence of interval censoring using parametric models.
In a retrospective cohort study, 178 patients with gastric cancer were studied from February 2003 to January 2008. Gender, age at diagnosis, distant metastasis, tumor size, histology type, tumor grade, lymph node metastasis and pathologic stage were selected as prognostic and entered in the models. Weibull, exponential, log-logistic and log-normal analyses with interval censoring were performed as parametric models, and Akaike Information Criterion (AIC) was used to compare the efficiency of models.
The risk of death for patients at an older age, with tumor size greater than 35 mm, distant metastasis and advanced stage of disease was statistically higher. Other clinical and demographic factors were not significant. According to AIC, the log logistic model is the most efficient of all the models in multivariable analysis.
The results indicated that the early detection of a cancer at a young patient age and in primary stages is important to increase survival from gastric cancer. According to statistical criteria, a parametric model can also be a useful statistical model to find prognostic factors in the presence of interval censoring. Although it seems that all models in this analysis fit well, AIC supported the log logistic regression as the best option.
本研究的目的是使用参数模型评估预后因素对存在区间删失的胃癌患者生存的影响。
在一项回顾性队列研究中，对2003年2月至2008年1月期间的178例胃癌患者进行了研究。选择性别、诊断时年龄、远处转移、肿瘤大小、组织学类型、肿瘤分级、淋巴结转移和病理分期作为预后因素并纳入模型。采用区间删失的威布尔、指数、对数逻辑斯蒂和对数正态分析作为参数模型，并使用赤池信息准则（AIC）比较模型的效率。
年龄较大、肿瘤大小大于35mm、有远处转移和疾病晚期的患者死亡风险在统计学上更高。其他临床和人口统计学因素不显著。根据AIC，在多变量分析中，对数逻辑斯蒂模型是所有模型中效率最高的。
结果表明，在年轻患者年龄和疾病早期阶段早期发现癌症对于提高胃癌患者的生存率很重要。根据统计标准，参数模型在存在区间删失的情况下也可以是寻找预后因素的有用统计模型。尽管在此分析中所有模型似乎都拟合良好，但AIC支持对数逻辑斯蒂回归作为最佳选择。
