Experts explain how laryngeal tumors spread and metastasize

Laryngeal cancer is a common malignant tumor in the Department of Otolaryngology. Although laryngeal cancer is not as common as cervical, breast, gastrointestinal and nasopharyngeal cancers, our experts will briefly introduce how laryngeal tumors spread. We hope it will be helpful to you!

It is so common that its incidence ranks 19th among all malignant tumors, but it ranks third among malignant tumors of the otolaryngology department, second only to nasopharyngeal carcinoma and nasal cancer, accounting for 11.7%-22% of otolaryngology cancers. It also occupies a very important position in malignant tumors of the respiratory system.

How laryngeal tumors spread and metastasize is mainly reflected in the following aspects:

1. Direct spread. The larynx is protected by the thyroid cartilage, so it spreads outwards relatively slowly. The first way to spread directly is to manifest along the cervical lamina, and then to infiltrate under the cervical lamina to expand the lesion. Vocal cord cancer mainly spreads backwards, forwards through the anterior commissure to the opposite vocal cord, and backwards to the choroid cartilage, but rarely to the laryngeal ventricular zone. Supraglottic cancer develops faster, and is most likely to spread to the pre-epiglottic space or invade the piriform sinus along the epiglottic folds, and can also develop along the pharyngeal epiglottic folds to the epiglottic valley and the root of the tongue on the posterior pharyngeal wall. Subglottic cancer often develops forwards and downwards, invading the opposite subglottis, but rarely backwards. Studies on laryngeal embryology have shown that supraglottic and subglottic tissues come from different primordia. The supraglottis develops from the buccal pharyngeal primordium, and the glottis and subglottis develop from the tracheobronchial primordium.

These two different primordia have different lymphatic circulation pathways. Therefore, the way laryngeal cancer spreads is limited to or first limited to the scope of embryonic demarcation. According to this understanding, supraglottic cancer rarely crosses the glottis to develop subglottis, and subglottic cancer rarely spreads to the supraglottis.

2. Lymphatic metastasis Laryngeal cancer can metastasize through the lymphatic system. The first to appear is the cervical lymph nodes. The glottic type has few lymphatic vessels in the vocal cords, so metastasis occurs later. The supraglottic type has abundant lymphatic tissue and lymphatic metastasis occurs earlier. The early or late appearance of lymph node metastasis is related to the primary site and clinical stage of the above-mentioned lesions, as well as the histological characteristics of the tumor. Clinical statistics show that non-invasive carcinoma in situ has almost no lymph node metastasis. About 30% of patients with invasive cancer have lymph node metastasis.

If the lesion is limited to the glottis, the chance of metastasis is less than 1%. However, if the lesion has invaded the laryngeal ventricle, laryngeal vestibule, subglottic area, or the primary site of the tumor is in the laryngeal vestibule, there is about a 30% chance of cervical lymph node metastasis. Cancers in the margin of the laryngeal vestibule or the pyriform sinus have a higher chance of cervical lymph node metastasis, up to about 50%. In summary, it can basically be considered that vocal cord cancer has a very low chance of metastasis, but the farther the primary or spread is from the vocal cords, the higher the chance of metastasis. Cervical lymph node metastasis is also related to the differentiation level of tumor cells.

Some literature suggests that patients with grade I differentiation have almost no cervical lymph node metastasis; patients with grade E differentiation have cervical lymph node metastasis in about 20%; patients with grade D differentiation have cervical lymph node metastasis in 40%-50%; and patients with grade IV differentiation have cervical lymph node metastasis in up to 70%. Due to different staging and classification of cases reported by different authors, the cervical lymph node metastasis rate in the literature discussing cervical lymph node metastasis ranges from 56% to 74%.

3. Blood metastasis Blood metastasis of laryngeal cancer is not common, usually occurs in the late stage, and is a manifestation of widespread metastasis throughout the body. Only a few patients in the early stage can metastasize to other parts of the body, internal organs or bones through the blood circulation. Among all laryngeal cancer patients, less than 5% have blood metastasis. When analyzing the causes of blood metastasis, some people believe that it may be that the tumor directly erodes the blood vessel wall and allows cancer cells to enter the blood circulation, or that it first invades the lymphatic vessels and then enters the veins and spreads with the blood.

Do you know how laryngeal tumors spread as briefly introduced by the above experts? Do you have any questions? Welcome to consult our online experts. I believe our experts will give you a satisfactory answer!

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