DISEASE CHARACTERISTICS: Histologically confirmed small cell lung cancer Must have received one prior chemotherapy regimen and relapsed OR Diagnosis of metastatic breast cancer No more than two prior chemotherapy regimens for metastatic disease Measurable disease Prior radiotherapy to measurable lesion allowed if progressed since treatment No diffuse bone marrow involvement on OctreoScan scintigraphy Positive for somatostatin receptors (grade 3 or 4) by Octreoscan scintigraphy No unstable brain metastases within the past 6 months Hormone receptor status: Not specified