What are the early metastatic sites of breast cancer?

Breast cancer is a serious cancer in life, because the mortality rate of breast cancer is very high, almost more than half of breast cancer patients will eventually lose their lives, so the prevention and treatment of breast cancer is very critical. The reason why breast cancer is so harmful is that it can quickly metastasize to other parts and cause large-scale tissue lesions. Let's take a look at the early metastatic sites of breast cancer.

(1) Direct infiltration: breast cancer cells directly invade surrounding tissues such as the skin, pectoral fascia, and pectoral muscles.

(2) Lymphatic metastasis: the spread of cancer cells through the output pathway of breast lymph. It includes the following four pathways: ① Cancer cells invade the ipsilateral axillary lymph nodes through the lymphatic vessels at the lateral edge of the pectoralis major muscle, and further invade the subclavian lymph nodes and even the supraclavicular lymph nodes. If it exceeds the supraclavicular lymph nodes, it can invade the venous blood flow through the thoracic duct (left) or right lymphatic duct and metastasize to distant sites. ② Cancer cells invade the parasternal lymph nodes medially and then reach the supraclavicular lymph nodes. They can then invade the venous bloodstream through the same pathway. ③ Cancer cells metastasize to the other breast through the subcutaneous lymphatic vessels of both breasts. ④ Cancer cells pass through the deep lymphatic network to reach the lymphatic vessels of the rectus sheath and the falciform ligament of the liver, and finally reach the liver. Lymphatic metastasis is mainly through the first two pathways. According to the results of pathological specimen examination of expanded radical resection of breast cancer in various parts of my country, the axillary lymph node metastasis rate is about 60%, and the parasternal lymph node metastasis rate is about 30%~35%.

3) Hematogenous metastasis: cancer cells metastasize to distant sites through the blood. It usually occurs in the late stage of breast cancer. In addition to entering the veins through the above-mentioned lymphatic pathways, cancer cells can also directly invade the blood circulation. The most common distant metastases are lung, bone, and liver. In bones, they are vertebrae, pelvis, and femur. Current research on breast cancer metastasis suggests that breast cancer is a systemic disease. Even in the early stages of the disease, or even in the subclinical stage, cancer cells can metastasize through the blood circulation and spread throughout the body. Tumor metastasis can occur in five-step jumps, not necessarily from near to far. Regional lymph nodes are not necessarily the intermediate pathway for tumor metastasis. This has guiding significance for the surgical methods and comprehensive treatment of breast cancer.

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