Association between KRAS mutation and lung metastasis in advanced colorectal cancer.

494 Background: The role of KRAS status in the time-dependent pattern of metastasis in colorectal cancer (CRC) patients has been reported but not validated in independent series of unresectable metastatic CRC. We aimed to determine its potential value as a predictive factor for development of lung metastasis. Methods: We retrospectively evaluated data from MD Anderson Cancer Center from 494 patients diagnosed with metastatic CRC with KRAS mutation testing (codons 12, 13, 61) by Sanger sequencing or mass spectroscopy genotyping in 2008 through 2010. Medical records and image reports were assessed to determine date of lung metastasis diagnosis, pattern of lung involvement and presence of thoracic lymph nodal metastasis. Time-to-lung metastasis (TTLM), lung-metastasis-free survival (LMFS) and overall survival (OS) were calculated from the time of diagnosis of first metastasis in any site according to the Kaplan-Meier method and were compared by log-rank test. Results: We included 494 patients (41% female) wi...