If there is still a thread after removing the drainage tube after lung cancer surgery, it is generally recommended to remove it, otherwise the body may have rejection reaction and inflammation. There are two incisions in thoracic surgery for lung cancer, one is the location where the drain tube is placed after surgery, and the ligated thread knot can be seen after the tube is removed, counting from the time of tube removal, and the thread is removed after 2 weeks. The other long incision is the surgical operation incision, which is made with absorbable sutures that are placed within the skin. If the knot is not exposed, there is no need to remove the suture. Timely judgment is made according to the patient’s drainage status, the difference in the patient’s postoperative site and the difference in the time of suture removal, and other conditions. First of all, it is recommended to go to the hospital to check the patient’s own condition, and after the doctor’s diagnosis, it is necessary to actively deal with the retention of stitches to prevent the body’s rejection reaction. If it can be removed as soon as possible, it is recommended that the patient according to the doctor’s advice in conjunction with the actual situation.