The Presence of Mutations in the K-RAS Gene Does Not Affect Survival after Resection of Pulmonary Metastases from Colorectal Cancer

Introduction. Our objective was to identify mutations in the K-RAS gene in cases of pulmonary metastases from colorectal cancer (CRC) and determine whether their presence was a prognostic factor for survival. Methods. We included all patients with pulmonary metastases from CRC operated on between 1998 and 2010. K-RAS mutations were investigated by direct sequencing of DNA. Differences in survival were explored with the Kaplan-Meier method log-rank tests and multivariate Cox regression analysis. Results. 110 surgical interventions were performed on 90 patients. Factors significantly associated with survival were disease-free interval (P = 0.002), age (P = 0.007), number of metastases (P = 0.001), lymph node involvement (P = 0.007), size of the metastases (P = 0.013), and previous liver metastasis (P = 0.003). Searching in 79 patients, K-RAS mutations were found in 30 cases. We did not find statistically significant differences in survival (P = 0.913) comparing native and mutated K-RAS. We found a higher rate of lung recurrence (P = 0.040) and shorter time to recurrence (P = 0.015) in patients with K-RAS mutations. Gly12Asp mutation was associated with higher recurrence (P = 0.022) and lower survival (P = 0.389). Conclusions. The presence of K-RAS mutations in pulmonary metastases does not affect overall survival but is associated with higher rates of pulmonary recurrence.