van Dijk M R, Steyerberg E W, Stenning S P, Dusseldorp E, Habbema J D F
Department of Public Health, Erasmus MC - University Medical Center Rotterdam, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
Br J Cancer. 2004 Mar 22;90(6):1176-83. doi: 10.1038/sj.bjc.6601665.
The International Germ Cell Consensus (IGCC) classification identifies good, intermediate and poor prognosis groups among patients with metastatic nonseminomatous germ cell tumours (NSGCT). It uses the risk factors primary site, presence of nonpulmonary visceral metastases and tumour markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and lactic dehydrogenase (LDH). The IGCC classification is easy to use and remember, but lacks flexibility. We aimed to examine the extent of any loss in discrimination within the IGCC classification in comparison with alternative modelling by formal weighing of the risk factors. We analysed survival of 3048 NSGCT patients with Cox regression and recursive partitioning for alternative classifications. Good, intermediate and poor prognosis groups were based on predicted 5-year survival. Classifications were further refined by subgrouping within the poor prognosis group. Performance was measured primarily by a bootstrap corrected c-statistic to indicate discriminative ability for future patients. The weights of the risk factors in the alternative classifications differed slightly from the implicit weights in the IGCC classification. Discriminative ability, however, did not increase clearly (IGCC classification, c=0.732; Cox classification, c=0.730; Recursive partitioning classification, c=0.709). Three subgroups could be identified within the poor prognosis groups, resulting in classifications with five prognostic groups and slightly better discriminative ability (c=0.740). In conclusion, the IGCC classification in three prognostic groups is largely supported by Cox regression and recursive partitioning. Cox regression was the most promising tool to define a more refined classification. British Journal of Cancer (2004) 90, 1176-1183. doi:10.1038/sj.bjc.6601665 www.bjcancer.com Published online 24 February 2004
国际生殖细胞共识（IGCC）分类法可识别转移性非精原细胞性生殖细胞肿瘤（NSGCT）患者的预后良好、中等和不良组。它使用的风险因素包括原发部位、非肺内脏转移的存在以及肿瘤标志物甲胎蛋白（AFP）、人绒毛膜促性腺激素（HCG）和乳酸脱氢酶（LDH）。IGCC分类法易于使用和记忆，但缺乏灵活性。我们旨在通过对风险因素进行正式加权的替代建模，来检验IGCC分类法在辨别能力上的损失程度。我们用Cox回归和递归分割法分析了3048例NSGCT患者的生存率，以进行替代分类。预后良好、中等和不良组是基于预测的5年生存率划分的。通过对预后不良组进行亚组划分，对分类进行了进一步细化。主要通过自展校正c统计量来衡量分类表现，以表明对未来患者的辨别能力。替代分类中风险因素的权重与IGCC分类法中的隐含权重略有不同。然而，辨别能力并没有明显提高（IGCC分类法，c = 0.732；Cox分类法，c = 0.730；递归分割分类法，c = 0.709）。在预后不良组中可识别出三个亚组，从而产生了具有五个预后组且辨别能力稍强的分类（c = 0.740）。总之，三个预后组的IGCC分类法在很大程度上得到了Cox回归和递归分割法的支持。Cox回归是定义更精细分类的最有前景的工具。《英国癌症杂志》（2004年）90卷，1176 - 1183页。doi:10.1038/sj.bjc.6601665 www.bjcancer.com 2004年2月24日在线发表
