What is the metastatic pathway of lung cancer

What are the metastatic pathways of lung cancer? When lung cancer becomes malignant in the later stages, it will often spread to different organs and cause corresponding symptoms, which often bring great pain to patients and even threaten their lives. The growth rate, spread and metastasis of lung cancer are determined by the histological type and degree of differentiation of cancer cells and the patient's immune function. Generally, there are several pathways.

1. Local direct spread

After the tumor occurs in the bronchial wall, it can grow into the bronchial cavity, causing the cavity to be narrowed or completely blocked. When the tumor grows outside the bronchus, it invades the lung tissue, and then spreads and expands to invade the adjacent organs and tissues. After central lung cancer spreads to the hilum and mediastinum, it can compress or invade the lymph, blood vessels, nerves, and various organs and tissues located in the mediastinum. Peripheral lung cancer near the edge of the lung often invades the pleura, causing pleural effusion and chest wall metastasis. The tumor can also penetrate the interlobar fissure and invade other adjacent lobes. Huge tumors form cancerous cavities due to ischemia, tissue necrosis, and liquefaction in the central part.

2. Transfer to Badao

Lymphatic metastasis is a common and main route of spread of bronchogenic lung cancer. Undifferentiated small cell carcinoma can metastasize through the lymphatics at an early stage, and squamous cell carcinoma metastasizes through the lymphatics very frequently. Adenocarcinoma often metastasizes through the blood vessels, but lymphatic metastasis can also occur. Cancer cells first invade the adjacent lung segments or lobes, parabronchial lymph nodes through the lymphatic ducts around the bronchi and pulmonary blood vessels, and then reach the hilum, subtracheal carina, mediastinum, paratracheal lymph nodes according to the location of the lung cancer, and then involve the supraclavicular, anterior scalene muscles and cervical lymph nodes. Metastasis of the mediastinal paratracheal and cervical lymph nodes generally occurs on the same side of the lung cancer, while lymphatic metastasis of left-sided lung cancer can occur on the opposite side of the lung cancer, which is the so-called cross-metastasis. After lung cancer invades the chest wall and diaphragmatic pleura, it can metastasize to the axillary, cervical and upper abdominal lymph nodes through the lymphatics.

3. Hematogenous metastasis

Cancer that metastasizes to the bloodstream is already in the advanced stage. Undifferentiated cancer can metastasize to the bloodstream relatively early. Adenocarcinoma metastasizes more often to the bloodstream. Advanced squamous cell carcinoma metastasizes to the bloodstream as well. Cancer cells usually invade the pulmonary venous system and then metastasize to organs and tissues throughout the body through the left heart and the systemic blood flow. The most common sites of metastasis are the liver, bones, adrenal glands, kidneys, brain, etc.

4. Airway spread

In some lung cancer cases, cancer cells shed from the lung can spread through the trachea and implant into other lung segments or lobes on the same or opposite side, forming new cancer foci. Bronchioloalveolar carcinoma is more likely to spread through the airways.