DISEASE CHARACTERISTICS: Histologically or cytologically confirmed limited or extensive stage small cell lung cancer (SCLC) Disease recurring at least 90 days following completion of first line chemotherapy Partial or complete response to first line therapy Must have at least one bidimensionally measurable non CNS lesion May be within a prior radiation port if at least 6 weeks since prior radiotherapy and progressing Brain and/or leptomeningeal metastases allowed if asymptomatic and not requiring corticosteroids