Patient: Patient: male, 60 years old, cough in December ’09, 2*3 nodules in lung trachea with mediastinal lymphatic metastases on CT in March this year, suspected tumor. After admission, fiberoptic bronchoscopy biopsy was done and small cell lung cancer was confirmed. Later, a whole-body bone scan revealed multiple bone metastases in the thoracic and lumbar spine. Brain ECT and liver ultrasound did not find metastases. Treatment: ep carboplatin + pedialyte glycoside chemotherapy, spot iban phosphate sodium. Effect: The lung tumor basically disappeared after 4 courses of treatment, and there was no significant pain in the bones. What should be the treatment at this stage?