With the prolongation of life expectancy in Japan, lung cancer is increasing not only in the elderly but also in poor-risk patients who can not undergo standard chemotherapy. Because survival benefits from chemotherapy are clearly expected in patients with small-cell lung cancer (SCLC), standard chemotherapy should be established for the elderly as well as for poor-risk patients with SCLC. We recently reported that the combination of AUC-based carboplatin and a standard dose of intravenous etoposide was an active and relatively nontoxic regimen for elderly patients with SCLC (J Clin Oncol 17: 3540-3545, 1999). Had chemotherapy with concurrent chest irradiation been used for patients with limited disease (LD), better survival might have been achieved in this study. However, Pignon et al. reported that combined chemoradiotherapy in elderly patients with LD-SCLC is a possible poor prognostic factor in their meta-analysis. A recent randomized controlled clinical trial has shown that vinorelbine monotherapy contributed to longer survival in elderly patients with advanced non-small-cell lung cancer (NSCLC), compared to best supportive care. Several retrospective studies have shown that cisplatin can be safely and effectively administered to elderly patients who are eligible for protocol treatment. However, there have been no randomized trials indicating that cisplatin-based combination chemotherapy improves survival in elderly patients with advanced NSCLC, compared to single-agent chemotherapy. Similarly, the role of combined chemoradiotherapy remains controversial in elderly patients with locally advanced NSCLC. Thus, standard therapies proven to be beneficial to non-elderly patients with lung cancer have not always been proven to be beneficial to elderly patients. In order to solve these difficult problems, phase III studies are warranted in elderly or poor-risk patients with lung cancer. Moreover, new agents with relatively low toxicities recently approved in Japan should be applied in clinical trials for the elderly or poor-risk patients with lung cancer.