OBJECTIVES: I. Determine the tumor response rate of yttrium Y 90 SMT 487 in patients with refractory small cell lung cancer or advanced metastatic breast cancer expressing somatostatin receptor. II. Determine the safety of this treatment regimen in these patients. III. Determine the overall survival of these patients with this treatment regimen. IV. Determine the quality of life in these patients with this treatment regimen. V. Determine the frequency of tumors which are positive (3+ or 4+) for OctreoScan scintigraphy in this patient population.