Purpose: Adenoid cystic carcinoma of head and neck (AdCCHN) is salivary gland malignancy known for its slow progression accompanied with perineural invasion, rare lymphatic spread to the neck, high rate of local recurrence and delayed onset of distant metastases. While local recurrence and distant metastases are most common patterns of relapse and cause of death in AdCCHN, it has been debated whether lymph node involvement affects the course of the disease. The aim of this systematic review was to address this important issue and to recommend guidelines on clinically node-negative neck management in patients with AdCCHN.
Methods: A systematic review of the published literature on cases of elective neck dissection (END) among patients with AdCCHN was performed.
Results: This analysis included a total of 5767 AdCCHN patients with 2450 ENDs, ranging from 10 to 1190. Elective lymphadenectomy was employed in 42.5% of patients with AdCCHN (range 9.2-100%). The overall rate of occult neck metastases in patients with AdCCHN was reported to range between 0 and 43.7%, the average being 13.9%.
Conclusions: If performed, END should be limited to levels I-III of the ipsilateral neck since occult metastases are exclusively located within these neck regions. Although END is associated with a prolonged regional recurrence-free period, it influence on final outcome or survival is still controversial. This review strongly supports conduction of prospective trials on indications, prognostic significance and extent of END in AdCCHN.
Keywords: Adenoid cystic carcinoma; Elective neck dissection; Head neck; Occult neck metastasis; Recurrence; Survival.