Outcome of pulmonary metastasectomy of colorectal cancer followed by adjuvant chemotherapy according to the prognostic index: A subset analysis of prospective multicenter study

Primary outcome(s): Evaluation of the ability and reproducibility of risk classification by the prognostic index.主要结局指标：评估预后指数（prognostic index）开展风险分类的能力及其可重复性。