Common metastasis patterns of laryngeal cancer

The main ways of metastasis of laryngeal cancer include direct spread, lymphatic metastasis, hematogenous metastasis, and implantation metastasis. Understanding these ways of metastasis will help us better treat it.

Direct Diffusion

The spread of the larynx is from the mucosal surface to the submucosal infiltration. Supraglottic cancer develops faster and is most likely to spread to the pre-epiglottic space, or invade the pyriform sinus along the epiglottic folds, or develop along the pharyngeal epiglottic folds to the epiglottic valley and tongue root of the posterior pharyngeal wall. Subglottic cancer often develops forward and downward, invading the contralateral subglottis, but rarely invades backward. Vocal cord cancer mainly spreads backward, forward through the anterior commissure to the contralateral vocal cord, and posteriorly to the arytenoid cartilage, but rarely invades the laryngeal ventricular zone upward.

Lymphatic metastasis

Patients with laryngeal cancer that has metastasized through the lymph nodes will develop cervical lymph nodes, which is a symptom of swollen necks. Since the vocal cords of glottic laryngeal cancer have very few lymphatic vessels, metastasis occurs later; supraglottic laryngeal cancer contains abundant lymphatic tissue and metastasis occurs earlier. The early or late occurrence of lymphatic metastasis is not only related to the site of the lesion and clinical stage, but also to the histological characteristics of the tumor. About 30% of patients with invasive laryngeal cancer have lymphatic metastasis, while non-invasive carcinoma in situ has almost no lymphatic metastasis. If the lesion is limited to the glottis, the chance of laryngeal cancer metastasis is less than 1%.

Lymph node metastasis is also related to the differentiation level of tumor cells: patients with grade I laryngeal cancer basically have no lymph node metastasis; about 20% of grade II patients have lymph node metastasis; for those with grade III differentiation, 40% to 50% have cervical lymph node metastasis; and the lymph node metastasis rate of grade IV patients can be as high as 70%.

Hematogenous metastasis

Hematogenous metastasis of laryngeal cancer is uncommon. Among all patients, less than 5% have hematogenous metastasis. It usually occurs in the late stage of laryngeal cancer and is a manifestation of widespread metastasis throughout the body.

Implant transfer

Tumor cells shed from laryngeal cancer can enter the bronchi or lungs during breathing and cause implantation metastasis. Up to 73% of laryngeal cancer patients develop lung metastasis.