Lung cancer metastasis route The most terrible thing about lung cancer is metastasis. Once the cancer cells metastasize, patients will suffer more pain and it is not easy to control the disease, which is one of the reasons why many lung cancer patients lost their lives. So, what are the ways of lung cancer metastasis? Direct diffusion The growing cancer in the lumen can block the bronchial tubes and cause obstructive pneumonia or pulmonary atelectasis. The cancer also expands into the lung tissue outside the bronchus. Tumors close to the periphery of the lung may invade the pleura and chest wall, while those in the central type or near the mediastinum may invade other organs such as large blood vessels and heart. Hematogenous metastasis After the cancer cells return to the left heart with the pulmonary vein, they can metastasize to any part of the body. The common sites of metastasis are liver, brain, lung, skeletal system, adrenal gland, kidney and pancreas, subcutaneous tissue, etc. This is the late manifestation of lung cancer. Endobronchial dissemination Cancer cells on the walls of fine bronchi and alveoli can be easily shed, and the cancer cells can spread through the bronchial tubes and even into the adjacent lung tissues to form new cancer foci. Lymphatic metastasis The lymphatic drainage of the lung has a certain pattern: the upper lobe of the right lung flows to the right hilar and right upper mediastinal lymph nodes. The middle lobe of the right lung drains to the lymph nodes of the middle and lower lobe summary areas, the inferior ramus and the right upper mediastinal lymph nodes. The lower lobe of the right lung drains to the summary zone of the middle and lower lobes, the inferior ramus, the inferior pulmonary ligament, and the right upper mediastinal lymph nodes. The upper lobe of the left lung leads to the subaortic arch lymph nodes and the left anterior superior mediastinal lymph nodes. Lymphatic flow in the lower lobe of the left lung leads to the upper and lower lobe summary areas, inferior to the ramus and across the mediastinum to the right upper mediastinal lymph nodes. The site of lymph node metastasis determines the clinical stage of lung cancer and has important reference value for treatment.