Lung cancer is the leading cause of cancer deaths worldwide, including Taiwan. Lung cancer in young patients (less or equal to 45 years) is uncommon and has clinical characteristics different from that in older patients. The incidence of lung cancer among young adults has been found to be around 5.3%. However, previous reports have shown trends of increasing incidence rates of lung cancer among young patients. Lung cancer in young adults has several unique characteristics: a high percentage of female patients, more adenocarcinoma, more advanced stage at the time of diagnosis, and more patients receiving aggressive treatment. The treatment outcomes for lung cancer in young adults remain controversial. These inconsistent findings could be related to different treatment modalities and ethnicities of patients. We investigated the outcomes and prognostic factors of young patients with advanced non-small cell lung cancer (NSCLC). Low BMI, stage IV disease, anemia at diagnosis, and male gender were the negative prognostic factors for young patients with advanced NSCLC.

　　For elderly patients with lung cancer, we may need to clarify the patients' age with respects to chronologic age (65 vs. 70 y/o), physiologic age (performance status, comobidities), and cellular ages (mutation potential, telomere shortening, immune dysregulation, increased susceptibility to oxidative stress).

　　In the 90’s, more than 50% of patients with advanced NSCLC at diagnosis were older than 65 years. According to the Surveillance, Epidemiology, and End Results (SEER) data in the United States, the median age of lung cancer patients is 71 years (70 in males and 71 in females). In Taiwan, the median age of lung cancer patients is 71 in males and 68 in females. Lung cancer has become a disease of the elderly.

　　For elderly patients, deterioration in cardiovascular and pulmonary functions may be the major concerns while considering curative surgery and radiotherapy. The decline of drug metabolizing capability and reduced bone marrow, liver and renal functional reserves may limit the use of chemotherapy. Thus, the optimal treatment for lung cancer in elderly patients may be different from those in younger patients.

　　In most clinical trials for lung cancer, there is a significant under-representation of elderly patients. The elderly-specific studies for lung cancer are relatively few. Data for elderly patients usually come from subset analyses of large-scale clinical trials. A review reported that selected elderly patients with local and locally advanced lung cancer could tolerate surgery, radiotherapy, and chemoradiation. Other studies also demonstrated that selected elderly patients could tolerate and benefit from chemotherapy. However, there are limited data describing the specific therapies for patients aged 70 or older.

　　For elderly patients who need surgical resection, Age should not be included as a criterion. Comorbidities (cardiopulmonary diseases) and predicted post-OP pulmonary function are important for the selection of patients for surgical resection. If carefully selected, the outcome for elderly patients who undergo surgical resection are similar to that of the younger patient. Dementia and disability in performing ADL were associated with postoperative complications. Congestive heart failure and prior myocardial infarction might be associated with an increased mortality in octogenarian.

　　The optimal treatment for elder patients with locally advanced NSCLC remains controversial. For stage IIIB NSCLC patients, No difference in response rate or survival by age was found. There were increased neutropenia and renal toxicity in older patients. For elderly patients with metastatic NSCLC, platinum-based doublet therapy will improved response rate and might prolong survival, with more leukopenia, thrombocytopenia, and anemia. EGFR-tyrosine kinase inhibitors may be beneficial for patients with certain EGFR mutation, both in younger and elderly patient groups. Further elderly-specific studies on optimal treatment of lung cancer are warranted