What are the chances of cancer with enlarged left hilar, mainly divided into the following cases, if a patient who has been smoking for a long time, recently develops irritating cough, coughing up sputum, even blood in sputum, chest pain, and the imaging suggests that the left hilar is enlarged, it needs to be highly suspected of centralized lung cancer. In this case, further fiberoptic bronchoscopy should be given to obtain pathological tissue as early as possible in order to create a chance of surgery. If the chance of surgery is lost with only chemotherapy and other treatments, the general survival period is about 1 year. If the left hilar enlargement is seen in patients who are emaciated and diabetic, it should not only be considered as a neoplastic lesion, but also need to be investigated for the possibility of tuberculosis, and the chance of cancer is relatively small. If the left hilar enlargement is seen in lymph node enlargement caused by malignant lymphoma as well as lymphatic hilar occupancy, this situation belongs to hematologic tumors, and the chance of cancer is more than 90%. In conclusion, left hilar enlargement is mainly based on whether the patient has been smoking for a long time, whether he/she has recently lost weight and whether he/she has blood in sputum, etc. If he/she has the above mentioned symptoms, the chance of cancer is often greater than 90%, and he/she needs to be further examined for diagnosis and treatment.