Age at diagnosis is a heterogeneous factor for non-small cell lung cancer patients

Lung cancer is the second most common malignant cancer and the leading cause of death from malignancy in the United States (1). Moreover, the prevalence of lung cancer has paralleled our increased life expectancy, with the median age at diagnosis 63 years (2). Elderly patients exhibit higher rates of mortality than younger patients with various solid cancers, regardless of the clinical characteristics of the primary tumor, including patients with advanced or metastatic non-small cell lung cancer (NSCLC) (3-5). In retrospective studies, younger lung cancer patients exhibited a higher incidence of adenocarcinoma, female, and an advanced stage disease (3,6). In addition, these patients tended to present with a higher malignant potential (7,8). Therefore, age is regarded as a heterogeneous fact for lung cancer patients. Interestingly, elder patients typically exhibit a lower frequency of lymph node metastasis, compared to patients with early-stage rectal cancer (9). The impact of age at diagnosis on clinicopathologic characteristics is not well known for lung cancer patients