Dokhi Mohammad, Ohtaki Megu, Hiyama Eiso
Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Hiroshima J Med Sci. 2009 Mar;58(1):25-35.
The log rank test and the Cox regression, or modifications thereof, emphasize the effect of covariates on survival rate parameter. In some cases, cured individuals, i.e., individuals who may not experience the event of interest may exist in the population of interest. In this situation, we may wish to examine the effect of covariates on both survival rate and cured fraction parameters. Motivated by the Japanese neuroblastoma dataset, we consider a cure model that accounted for the effect of covariates on both of the abovementioned parameters. To deal with heterogeneity that is not explained by covariates, as well as individual random heterogeneity, we perform a frailty variable. Moreover, some nested models are fitted to deal with the principle of parsimony. The effect of covariates was then evaluated by the best nested model. From a statistical point of view, we found that the model of analysis is flexible and adequate to describe the abovementioned dataset. From a medical point of view, we confirmed AGE and STAGE to be the most dominant prognosis factor of neuroblastoma. We also conclude that NMYC and FERRITIN are the other most important prognosis factors. The analysis designated that some of the prognosis factors of neuroblastoma probably just affected the median life of patients and some others are the fatal prognosis factor indicated by their effect which significance on both of survival rate and cured fraction parameters. The present model of analysis is also potentially extendable to facilitate other aspects of inferences.
对数秩检验和Cox回归及其改进方法，着重于协变量对生存率参数的影响。在某些情况下，感兴趣的总体中可能存在已治愈个体，即可能不会经历感兴趣事件的个体。在这种情况下，我们可能希望研究协变量对生存率和治愈比例参数的影响。受日本神经母细胞瘤数据集的启发，我们考虑一种治愈模型，该模型考虑了协变量对上述两个参数的影响。为了处理协变量无法解释的异质性以及个体随机异质性，我们引入了一个脆弱变量。此外，拟合了一些嵌套模型以遵循简约原则。然后通过最佳嵌套模型评估协变量的影响。从统计学角度来看，我们发现分析模型灵活且足以描述上述数据集。从医学角度来看，我们确认年龄和分期是神经母细胞瘤最主要的预后因素。我们还得出结论，NMYC和铁蛋白是其他最重要的预后因素。分析表明，神经母细胞瘤的一些预后因素可能仅影响患者的中位生存期，而其他一些则是对生存率和治愈比例参数均有显著影响的致命预后因素。当前的分析模型也可能具有可扩展性，以促进其他方面的推断。
