Clinicopathologic characteristics and survival outcome in patients with advanced lung adenocarcinoma and KRAS mutation

Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are one of the most common observed genetic events in lung adenocarcinoma. The present study aimed to characterize treatment patterns and to estimate survival for patients in China with advanced lung adenocarcinoma and KRAS mutation. We identified KRAS-mutant lung adenocarcinoma between February 2013 and June 2017 in Zhejiang Cancer Hospital. Patients' characteristics and treatment outcomes were analyzed. A total of 159 lung adenocarcinoma were included, and 26 (16.4%) patients harbored KRAS mutations. Compared to KRAS-wild patients, patients with KRAS-mutant tumors were more likely to be smokers (76.9% vs. 51.9%, P = 0.029). Median tumor mutation burden (TMB) was significantly higher in the KRAS-mutant cohort than in the KRAS-wild cohort (5.4 vs. 4.2 mutations/megabases; P=0.041). Of the 93 patients receiving first-line chemotherapy, the median progression-free survival (PFS) in the KRAS-mutant group was significantly shorter than in the KRAS-wild group (1.5 vs. 7.2 months; P<0.001). The median overall survival (OS) in the KRAS-mutant group was also significantly shorter than in the KRAS-wild group (hazard ratio for progression or death for patients with KRAS mutation, 3.260; 95% CI, 1.516 to 7.013; P=0.001). In summary, our findings have several important implications for the molecular characterization and therapeutic outcome of lung adenocarcinoma initiated by oncogenic KRAS. Since the number of KRAS-mutant lung cancer is considerable, it should be taken seriously in clinical diagnosis and treatment. KRAS-mutant lung adenocarcinoma was not sensitive to chemotherapy, new and effective drugs targeting the KRAS pathway are in urgent need.