Postrecurrence survival of surgically resected pulmonary adenocarcinoma patients according to EGFR and KRAS mutation status

The aim of this study was to investigate the prognosis of pulmonary adenocarcinoma patients following postoperative recurrence, according to epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) gene mutation status and recurrence site. In total 58 adenocarcinoma patients with recurrence following surgical resection were retrospectively evaluated between 2002 and 2011. The patients were divided into groups according to the presence or absence of EGFR and KRAS mutations and the clinicopathological characteristics, recurrence sites and postrecurrence survival were compared. EGFR and KRAS mutations were detected in 26 (45%) and 11 patients (19%), respectively. Initial recurrence was distant in 25 (43%), local in 17 (29%) and both distant and local in 16 cases (28%). In EGFR-mutant (EGFR+) cases, bilateral/contralateral lung recurrence was a frequent finding. EGFR+ cases exhibited significantly better outcomes compared to KRAS+ and EGFR-KRAS- (wild-type) cases. The 2-year post-recurrence survival rates were 81, 18 and 47% in EGFR+, KRAS+ and wild-type cases, respectively. The patients with distant organ recurrence exhibited significantly worse survival compared with those without distant recurrence in wild-type, but not in the EGFR+ cases or the entire cohort. Multivariate analysis revealed that EGFR mutations and a number of recurrent lesions were the only statistically significant independent predictors of postrecurrence prognosis. Our results indicated distinct survival differences in recurrent adenocarcinoma patients according to driver mutations. Patients with EGFR-mutated tumors exhibited increased survival, regardless of recurrence at distant sites, whereas patients with KRAS-mutated adenocarcinoma exhibited poor outcome following postoperative recurrence. Therefore, the assessment of driver mutations is essential for predicting postrecurrence survival following surgical resection.