Preoperative probability model for predicting overall survival after resection of pulmonary metastases from colorectal cancer

Abstract

Abstract Background The aim of this study was identify readily available factors most helpful in predicting survival and to develop a prognostic nomogram for patients with pulmonary metastases from colorectal cancer who are candidates for thoracotomy. Methods Pretreatment data on 313 patients with metastases who underwent thoracotomy were analysed. Fourteen preoperative clinical and pathological variables were used to develop a probability model, in which their association with 3-year survival was tested. A nomogram to predict median, 1- and 3-year survival was constructed and validated internally using the concordance index (c-index). The nomogram was then validated with an external data set. Results Five variables were identified as independent predictors of 3-year survival: prethoracotomy carcinoembryonic antigen level, number of pulmonary tumours, presence of hilar or mediastinal tumour-infiltrated lymph nodes, histology of the primary tumour and presence of extrathoracic disease. The nomogram was well calibrated for predicting 3-year overall survival. The internal validated c-index of the nomogram was 0·72. Applied to another data set, the external validated c-index was 0·66. Conclusion This model has moderate predictive ability to discriminate between patients who are likely to survive after thoracotomy for pulmonary metastases from colorectal cancer.