Upper limb lymphedema is one of the common complications after modified radical mastectomy, with an incidence of 6-14%. If left untreated, it will worsen progressively. Therefore, active and timely treatment and care are very important. 1.What are the causes of lymphedema after breast cancer surgery? Lymphatic reflux and blood return obstruction are the main causes after modified radical mastectomy for breast cancer. Since the removal of axillary lymph cuts off the lymphatic return pathway of the upper limb, the lymph in the upper limb cannot drain adequately, which increases the protein concentration in the interstitial fluid, which in turn attracts fluid into the tissue and also promotes inflammation and fibrosis. Circulation of lymphocytes and macrophages is impaired, and cell-mediated immunity of the skin is reduced, while postoperative scar formation and recurrent infections also exacerbate upper extremity edema. Radiotherapy can cause venous occlusion and lymphatic vessel destruction in the radiation field, causing local radioactive skin lesions and radioactive lymphangitis, and also affect upper limb reflux and upper limb function due to local muscle fibrosis compressing veins and lymphatic vessels. 2.How is lymphedema graded after mastectomy? (1) Mild edema: the circumference of the affected upper limb is less than 3 cm thicker than the healthy side, mostly limited to the proximal end of the upper arm, and often occurs within a short time after surgery. (2) Moderate edema: the circumference of the affected upper limb is 3-6 cm thicker than the healthy side, and the edema affects the entire upper limb, including the forearm and the back of the hand. (3) Severe edema: The circumference of the affected upper limb is more than 6 cm thicker than the healthy side, the skin is hard and tough, and the edema affects the whole upper limb including the fingers, so that the movement of the whole upper arm and shoulder joint of the patient is severely restricted. 3.The grading standard of the International Lymphatic Society on lymphedema: degree I: swelling with depression, swelling is reduced by elevating the limb; degree II: hard texture without depression, skin nail change, hair loss; degree III: elephantiasis, thick skin, one with huge folds. 4.Postoperative lymphedema has occurred, how to treat? Most of the mild and moderate upper limb swelling can be relieved by functional exercise after surgery, while severe swelling is difficult to be cured, mostly by comprehensive treatment, which includes Chinese and Western medicine treatment, physiotherapy and surgery. Mechanical physiotherapy is a conservative treatment method commonly used in clinical practice, among which functional exercises, local massage, compression with elastic bandage or air-filled balloon, microwave or infrared light are the most common methods. Mechanical physiotherapy is the basic treatment for breast cancer clearance and is used in combination with other treatment methods. Some studies have pointed out that the efficacy of conservative treatment such as functional exercise and compression with elastic bandage is obvious in the early stage of edema, but the efficacy decreases significantly when fibrosis occurs in the affected limb. The purpose of surgical treatment is to reduce the load on the lymphatic system and improve the transport capacity of the lymphatic system, and different surgical treatment methods are used according to the purpose. 5.The surgeon suggested me to see a Chinese medicine doctor, how can Chinese medicine treat (lympho)edema? Due to the limitation of modern medicine in the treatment of upper limb lymphedema, Chinese medicine has become a new idea and a new method to treat upper limb lymphedema. TCM is more effective in the conservative treatment of lymphedema of the upper extremities after breast cancer surgery. The use of evidence-based treatment and the addition and subtraction of drugs according to each patient’s specific condition can alleviate the clinical symptoms of postoperative lymphedema of the upper extremities after breast cancer surgery to different degrees, combined with the traditional topical creams of TCM to reduce swelling and disperse nodules, which has good clinical efficacy.