BACKGROUND Most current models for predicting survival after resection of colorectal liver metastasis include largest diameter and number of colorectal liver metastases as dichotomous variables, resulting in underestimation of the extent of risk variation and substantial loss of statistical power. The aim of this study was to develop and validate a new prognostic model for patients undergoing liver resection including largest diameter and number of colorectal liver metastases as continuous variables. METHODS A prognostic model was developed using data from patients who underwent liver resection for colorectal liver metastases at MD Anderson Cancer Center and had RAS mutational data. A Cox proportional hazards model analysis was used to develop a model based on largest colorectal liver metastasis diameter and number of metastases as continuous variables. The model results were shown using contour plots, and validated externally in an international multi-institutional cohort. RESULTS A total of 810 patients met the inclusion criteria. Largest colorectal liver metastasis diameter (hazard ratio (HR) 1.11, 95 per cent confidence interval 1.06 to 1.16; P < 0.001), number of colorectal liver metastases (HR 1.06, 1.03 to 1.09; P < 0.001), and RAS mutation status (HR 1.76, 1.42 to 2.18; P < 0.001) were significantly associated with overall survival, together with age, primary lymph node metastasis, and prehepatectomy chemotherapy. The model performed well in the external validation cohort, with predicted overall survival values almost lying within 10 per cent of observed values. Wild-type RAS was associated with better overall survival than RAS mutation even when liver resection was performed for larger and/or multiple colorectal liver metastases. CONCLUSION The contour prognostic model, based on diameter and number of lesions considered as continuous variables along with RAS mutation, predicts overall survival after resection of colorectal liver metastasis.

中文翻译：

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等高线预后模型，用于预测结直肠肝癌切除术后的生存：使用最大直径和具有RAS突变状态的转移灶的数量进行的发展和多中心验证研究。

背景技术目前大多数用于预测结直肠肝转移切除术后存活率的模型包括最大直径和结直肠肝转移数目作为二分变量，导致低估了风险变化的程度和统计学上的重大损失。这项研究的目的是为接受肝切除术的患者开发和验证一种新的预后模型，包括最大直径和结直肠肝转移的数量作为连续变量。方法使用MD Anderson癌症中心接受肝切除术的结直肠癌肝转移患者的数据建立预后模型，并获得RAS突变数据。使用Cox比例风险模型分析来建立基于最大结肠直肠肝转移直径和转移数目作为连续变量的模型。使用等高线图显示了模型结果，并在国际多机构队列中进行了外部验证。结果共有810名患者符合入选标准。大肠肝转移的最大直径（危险比（HR）1.11，95％置信区间1.06至1.16; P <0.001），大肠肝转移的数目（HR 1.06、1.03至1.09; P <0.001）和RAS突变状态（ HR 1.76，1.42至2.18； P <0.001）与总体生存率，年龄，原发性淋巴结转移和肝切除术前化疗显着相关。该模型在外部验证队列中表现良好，预测的总生存值几乎在观察值的10％之内。即使对较大和/或多个结直肠肝转移进行了肝切除，野生型RAS也比RAS突变具有更好的总体存活率。结论轮廓预后模型基于被认为是连续变量以及RAS突变的病变的直径和数量，可预测结直肠肝转移切除术后的总体生存率。