Genetic and prognostic differences of non-small cell lung cancer between elderly patients and younger counterparts

Many elderly patients suffer from lung cancers, but it is not clear if their lung cancers differ from those of younger patients. In this study, we compared genetic and prognostic characteristics of lung cancers of patients aged ≥75 years with those of patients aged ≤ 64 years. In the genetic analysis, we explored 292 surgically treated non-squamous cell lung cancers with known mutational status of epidermal growth factor (EGFR) and anaplastic lymphoma kinase (ALK). In the prognostic analysis, we retrospectively analyzed 405 surgically treated non-small cell lung cancers (NSCLCs) before the era of routine clinical application of post-surgical adjuvant chemotherapy. Postsurgical recurrence-free survival (RFS) was compared between elderly patients and younger counterparts. The genetic analysis showed elderly non-squamous cell lung cancer patients to have higher prevalence of EGFR mutations (53.1 % vs 42.0%, P = 0.15) and lower prevalence of the ALK translocation (0 % vs 4.5%, P = 0.23) than their younger counterparts. The prognostic analysis showed postsurgical RFS was similar between the elderly NSCLC patients and the younger patients. However in multivariate analysis, adjusting for gender, smoking status, pathological stage, and histology, elderly patients had significantly worse prognoses (HR 1.57, 95% CI, 1.08-2.29; P = 0.02) compared with younger patients. These results suggest differences in genetic and prognostic aspects between elderly lung cancer patients and younger lung cancer patients.