Laryngeal cancer is a common malignant tumor of the head and neck, and its incidence rate has been increasing significantly in recent years. The incidence rate of laryngeal cancer in some provinces and cities in China is about 1.5 to 3.4 per 100,000 people. 1983 to 1992, laryngeal cancer accounted for 13.9% of the head and neck tumors and 2.1% of the whole body malignant tumors in some hospitals in 13 provinces and cities in China. Laryngeal cancer is more common in men than women, about 7-10:1. The high incidence age of laryngeal cancer is 50-70 years old. The incidence rate of laryngeal cancer in North and Northeast China is much higher than that in Jiangnan provinces, and the incidence rate in urban areas is higher than that in rural areas, and the incidence rate in heavy industrial cities with heavy air pollution is higher than that in light industrial cities with light pollution. The etiology of laryngeal cancer is still not well understood, and it is related to the following factors, which are often the result of the synergistic effect of multiple carcinogenic factors. 1.Smoking: 95% of laryngeal cancer patients are long-term smokers. The burning of tobacco produces benzpyrene, which can cause congestion and edema of respiratory mucosa, stop or retard cilia movement, epithelial hyperplasia and squamous epithelial metaplasia, and become the basis of carcinogenesis. 2.Drinking alcohol: there is a correlation between chronic alcohol intake and the occurrence of laryngeal cancer. The risk of laryngeal cancer from alcohol consumption is 1.5 to 4.4 times that of non-drinkers. Supraglottic cancer may be related to alcohol consumption. Some scholars have confirmed that smoking and alcohol consumption have synergistic effects on carcinogenesis. 3.Air pollution: Long-term inhalation of large amount of production dust or exhaust gas, such as asbestos, mustard gas, nickel, chromium, sulfur dioxide, arsenic, etc., may cause cancer, so we must pay attention to the protection in industrial production. 4.Viral infection: Adult laryngeal papilloma is a virus-derived tumor caused by human papillomavirus (HPV), which is considered to be a precancerous lesion of laryngeal cancer. HPV-16 and 18 may be related to the occurrence of laryngeal cancer. 5.Pre-cancerous lesion: It refers to certain pathological changes that are more likely to become cancerous than normal mucosa or other benign lesions. Pre-cancerous laryngeal lesions laryngeal leukoplakia, severe atypical hyperplasia of vocal cords, adult-type chronic hypertrophic laryngitis and adult-type papilloma. These lesions can become cancerous under the effect of endogenous and exogenous harmful factors. 6.Sex hormones: Sex hormones and their receptors may be related to the development of laryngeal cancer. 7.Radiation: It has been reported that malignant tumors such as laryngeal cancer can be induced after head and neck radiotherapy in a few patients. Pathology】 Squamous cell carcinoma accounts for about 93%-99% of all primary laryngeal cancers, while adenocarcinoma and undifferentiated carcinoma are extremely rare. Early laryngeal squamous cell carcinoma is confined to the epithelial layer and the basement membrane is intact. If the cancer breaks through the epithelial basement membrane, it can form infiltrating nests in the lamina propria. Among laryngeal squamous cell carcinomas, those with better differentiation are the most common. Glottic carcinoma can occur in all areas of the larynx, but glottic carcinoma is the most common, accounting for about 60% of the cases, and is generally well differentiated and less metastatic. Supraglottic carcinoma is the second most common carcinoma, accounting for about 30% of the cases. It is generally poorly differentiated, metastatic and has a poor prognosis. Subglottic carcinoma is extremely rare. However, supraglottic carcinoma is predominant in northern China, especially in some areas of northeast China. The general morphology of laryngeal carcinoma can be divided into: ulcer-infiltrating type: the cancerous tissue protrudes slightly to the mucosal surface, and the sunken ulcer can be seen on the surface infiltrating to the deeper layer, with uneven border and unclear boundary; cauliflower type: the tumor mainly grows outwardly in the shape of cauliflower, with clear boundary, and generally does not form ulcer; nodular or mass type: the surface of the tumor is irregularly elevated or spherical elevated, with more complete peritoneum, clearer boundary, and rarely forms ulcer; mixed type: the tumor is irregularly elevated or spherical elevated, with more complete peritoneum, and rarely forms ulcer. Mixed type: it has the appearance of both ulcer and cauliflower type, with uneven surface and often deep ulcers. Secondary carcinoma of larynx is less common and usually spreads from thyroid, laryngopharynx and esophagus. Metastatic laryngeal cancer from distant places is rare, such as skin melanoma, breast cancer, adrenal cancer, etc. Diffusion and metastasis of laryngeal cancer] The diffusion and metastasis of laryngeal cancer are closely related to its primary site, differentiation degree, tumor size and patient’s immunity to tumor, etc. The ways are as follows: 1. Direct diffusion: laryngeal cancer easily spreads by mucosal surface or infiltrates to submucosa, which is the expansion of lesion. Epiglottis cancer can invade the anterior epiglottis space, epiglottis valley and tongue root forward. Aryepiglottic fold cancer can spread outward to the pyriform fossa and lateral wall of laryngopharynx. Carcinoma of the vocal folds may invade the anterior commissure and the contralateral vocal folds; it may also destroy the thyroid cartilage and enlarge the laryngeal body, and invade the soft tissues in front of the neck. Subsonic carcinoma spreads downward to the trachea, and can penetrate the cricothyroid membrane to the anterior cervical muscle layer, and invade the thyroid gland to both sides; and involve the anterior wall of esophagus backward. 2.Lymphatic metastasis: the early and late occurrence of cervical lymph node metastasis is closely related to the primary site of tumor, the differentiation degree of tumor and the immunity of patients against tumor. The worse the differentiation of the tumor and the lower the immunity of the patient, the earlier the cervical lymph node metastasis will occur. The richer the lymphatic vessels in the tumor site, the higher the rate of cervical lymph node metastasis. Most supraglottic cancers are less differentiated and have abundant lymphatic vessels in the supraglottic region, so they are prone to early cervical lymph node metastasis. Most of the cancers in the vocal tract are more differentiated and have few lymphatic vessels in the vocal tract, so metastasis rarely occurs in the early stage. The metastases are mostly found in the upper group of deep cervical lymph nodes, and then metastasize to the lower group of deep cervical lymph nodes along the internal jugular vein. Subglottic laryngeal cancer mostly metastasizes to anterior laryngeal and paratracheal lymph nodes. 3.Bloodstream metastasis: a few advanced patients can metastasize to lung, liver, bone, kidney, pituitary gland, etc. with blood circulation.