Brief description of typical medical history The patient was a male, 49 years old. Complaint: Left lung tumor was found for half a month. Current medical history: The patient was seen at an outside hospital in November 2011 for coughing, CT examination showed an occupancy in the upper lobe of the left lung, percutaneous lung puncture biopsy pathology report showed adenocarcinoma of the lung, and was referred to our hospital due to poor lung function. Past history: bronchial asthma for 10 years; smoked for 29 years with an average of 40 cigarettes/day. Zeng Zhaochong, Department of Radiotherapy, Zhongshan Hospital, Fudan University Before treatment Signs: KPS 90; no enlargement of superficial lymph nodes; clear breath sounds on auscultation of both lungs. Auxiliary examinations: routine blood tests showed RBC 5.2×1012/L, Hb 160 g/L, WBC 9.6×109/L; PET-CT (December 2011) showed peripheral type lung cancer in the upper lobe of the left lung with a tumor size of 2.1 cm×1.5 cm, SUV 11.8 g/ml, few chronic inflammation and old foci in both lungs, and emphysema in both lungs (see Figure 1A~B). Pulmonary function tests (December 2011) showed FEV1 0.45 L and severe obstructive predominantly mixed ventilation dysfunction. The patient was at high surgical risk. Diagnosis: peripheral type adenocarcinoma of the left lung, stage IA (cT1bN0M0). Treatment After a joint consultation between the pulmonary medicine, thoracic surgery and radiotherapy departments, SBRT was performed using TomoTherapy combined with 4-dimensional CT technique. the dose was 10 Gy/dose, 5 times/week, for a total dose of 50 Gy (Figure 2). Radiotherapy was not followed by chemotherapy. During and after radiotherapy, tiotropium bromide powder inhalation (1 inhalation/day) and salmeterol ticapone powder inhalation (1 inhalation/dose, 2 times/day) were given in the pulmonary medicine department for 2 months. After treatment The PET-CT examination was repeated 6 weeks after radiotherapy (February 9, 2012), which showed that the lesion in the upper lobe of the left lung was smaller than before, with a tumor size of 1.0 cm×0.8 cm and SUV 0.9 g/ml (Figure 1C~D). Pulmonary function showed that FEV1 rose to 0.67 L, but there was still severe obstructive ventilation dysfunction. Efficacy evaluation: The patient’s lung lesion was significantly reduced in SUV and tumor shrinkage after radiotherapy, and partial remission was achieved. Note: KPS Carlson functional status score; RBC red blood cells; Hb hemoglobin; WBC white blood cells; PET positron emission tomography; SUV standard uptake value; FEV1 1st second forceful expiratory volume; TomoTherapy spiral tomographic navigation adaptive radiotherapy system; SBRT stereotactic radiotherapy MDT Discussion Among patients diagnosed with non-small cell lung cancer, 16% of Stages I and II (lymph node negative), radical surgical resection has been the standard of care, with a 5-year postoperative survival rate of 70% to 80% of patients. information from the US Surveillance, Epidemiology and End Results (SEER) database from 1973-2007 shows that approximately 70% of early-stage patients underwent surgical resection and approximately 30% underwent conventional fractionated radiotherapy. The 5-year survival rate of patients after radiotherapy was 10%-30%, which was far inferior to that of surgical resection. after the 1990s, the application of 3D conformal radiotherapy technology has improved the dose of radiotherapy, the local control rate of tumor, and the long-term survival rate of patients. With the development of radiotherapy technology, SBRT was able to overcome the error caused by respiratory motion, thus focusing the radiation dose on the tumor. It has been reported that SBRT has a 3-year local tumor control rate of 90% and a long-term survival rate of 60% to 80%, which is comparable to the efficacy of surgery. As a treatment for early stage lung cancer that cannot tolerate surgery, SBRT has the advantages of non-invasive, short treatment time, outpatient treatment, and avoidance of postoperative complications. Currently, the National Comprehensive Cancer Network (NCCN) guidelines have included SBRT as a recommended treatment option for patients with surgery intolerant early-stage lung cancer, but it is still controversial whether it can be the standard treatment for stage I and II non-small cell lung cancer. In this case, the patient had stage I peripheral non-small cell lung cancer, and PET-CT showed no lymph node metastasis manifestation. Since lobectomy requires the patient to have an FEV1 of 1.5 L or more, and the patient had a history of severe bronchial asthma, pulmonary function tests showed an FEV1 of 0.45 L, and there was severe obstructive predominantly mixed ventilation dysfunction, it was clear that the surgery was risky. After consultation with the pulmonary medicine, radiotherapy and thoracic surgery departments, it was decided to treat him with SBRT, 10 Gy/dose, 5 times/week, with a total dose of 50 Gy (equivalent to a bioequivalent dose of 100 Gy or more), and the pulmonary physician gave simultaneous treatment to improve lung function during radiotherapy. When PET-CT was repeated 6 weeks after radiotherapy, not only the SUV of the lung lesion was reduced, the tumor shrunk, and there was no obvious sign of radiation lung injury, but also the patient’s lung function improved, indicating that SBRT is safe and effective for the treatment of early-stage non-small cell lung cancer patients with poor lung function, which also reflects the advantages of the multidisciplinary cooperative diagnosis and treatment model and is worth promoting.