Streaks in the lungs after breast cancer surgery are usually not due to metastasis of the disease. Possible causes include pneumonia, tuberculosis, or side effects of anti-tumor therapy. Streaks in the lungs after breast cancer surgery are usually seen in CT imaging of the lungs, which is mostly due to pneumonia, tuberculosis, or radiation pneumonitis caused by postoperative radiotherapy for breast cancer. Lung metastasis of breast cancer is mostly manifested as nodular shadows in both lungs, with nodules of different sizes and unclear borders with the surrounding. For different causes of lung nodular shadow, adopt corresponding treatment measures after clarifying the causes, such as choosing sensitive broad-spectrum antibiotic treatment for pneumonia, standardized anti-tuberculosis treatment for tuberculosis, and hormone combined with antibiotic treatment for radiation pneumonitis, etc., and most of the patients can get a better therapeutic effect.