Iressa vs Placebo as Maintenance Therapy in Locally Advanced NSCLC

Inclusion Criteria: * Histologically Confirmed Non Small Cell Lung Cancer. * Locally advanced disease previously treated with combined therapy (chemotherapy and surgery with or without radiotherapy, or chemotherapy and radiotherapy). * Chemotherapy with regimens containing cisplatin or carboplatin is mandatory * Response to combined therapy Exclusion Criteria: * No previous treatment with ZD1839 or any other EGFR-targeted therapy * No progressive disease after combined therapy for locally advanced NSCLC * No presence of metastatic disease * No other co-existing malignancies or malignancies diagnosed within the last 5 years with the exception of basal cell carcinoma or cervical cancer in situ * Any unresolved chronic toxicity from previous anticancer therapy.