BACKGROUND. Chemonaive patients had higher response rates than chemotherapy-treated patients in previous analyses of East Asian patients with advanced nonsmall cell lung cancer. The survival outcome and the predictors for antitumor activity in chemonaive patients who received gefitinib as first-line treatment are unclear. METHODS. Clinicopathologic predictive factors, objective tumor responses, and the survival of consecutive patients with advanced, chemonaive nonsmall cell lung cancer who received gefitinib as first- line treatment were collected and analyzed. Multivariate analysis was conducted to determine independent predictive factors for gefitinib antitumor efficacy. RESULTS. One hundred ninety-six patients (112 males and 84 females) were analyzed. Ninety-six patients (49%) were never smokers. One hundred forty-four patients (73%) had adenocarcinoma or bronchioloalveolar carcinoma histology. One hundred twenty patients had an Eastern Cooperative Oncology Group performance status 0 to 2. Eighty-three patients (42%; 95% confidence interval, 36-49% ) had an objective tumor response . An additional 35 patients had stable disease (disease control rate, 61%). The tumor response rate was 52% in patients who had a good performance status. Female gender, nonsmoking status, and adenocarcinoma histology all were independent predictors of response or disease control in multivariate analysis. The median survival was 11.1 months, and the 1-year survival rate of patients who had a good performance status was 47.5%. CONCLUSIONS. The response rate to gefitinib was high in East Asian chemonaive patients with advanced nonsmall cell lung cancer. Female gender, adenocarcinoma histology, and nonsmoking status all were independent predictors of gefitinib response. The survival outcome of these patients was similar to that of patients who initially received chemotherapy. (c) 2006 American Cancer Society. ; 附設醫院腫瘤醫學部 ; 醫學院附設醫院 ; 期刊論文