Adenoid cystic carcinomas:
A. Spread submucosallySquamous cell carcinomas often present with regional lymph node metastases and are frequently unresectable at presentation. Their biologic behavior is similar to that of squamous cell carcinoma of the lung. Adenoid cystic carcinomas, a type of salivary gland tumor, are generally slow-growing, spread submucosally, and tend to infiltrate along nerve sheaths and within the tracheal wall. Although indolent in nature, adenoid cystic carcinomas are malignant and can spread to regional lymph nodes, lung, and bone. Squamous cell carcinoma and adenoid cystic carcinomas represent approximately 65% of all tracheal neoplasms. The remaining 35% comprises small cell carcinomas, mucoepidermoid carcinomas, adenocarcinomas, lymphomas, and others.
ostoperative mortality, which occurs in up to 10% of patients, is associated with the length of tracheal resection, use of laryngeal release, the type of resection, and the histologic type of the cancer. Factors associated with improved longterm survival include complete resection and use of radiation as adjuvant therapy in the setting of incomplete resection. Due to their radiosensitivity, radiotherapy is frequently given postoperatively after resection of both adenoid cystic carcinomas and squamous cell carcinomas. A dose of 50 Gray or greater is usual. Nodal positivity does not seem to be associated with worse survival. Survival at 5 and 10 years is much better for adenoid cystic (73 and 57%, respectively) than for tracheal cancers (47 and 36%, respectively; P <0.05). For patients with unresectable tumors, radiation may be given as the primary therapy to improve local control, but is rarely curative. For recurrent airway compromise, stenting or laser therapies should be considered part of the treatment algorithm.