Occult Metastasis in Laryngeal Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

Objective: The incidence of occult metastasis (OM) in laryngeal squamous cell carcinoma (SCC) is still widely debated. In this systematic review, we aim to determine the rate of OM in laryngeal SCC, its impact on recurrence, and the role of elective neck dissection (END) in the management of the clinically negative neck. Methods: A systematic review of the English-language literature in Web of Science, PubMed, MEDLINE, and Cochrane Library databases on occult metastasis in laryngeal SCC from 1977 to 2018 was conducted. Studies evaluating occult metastasis (OM) in patients with laryngeal SCC with clinically negative necks undergoing surgery were included. Studies evaluating other head and neck subsites, clinically node positive, and salvage patients were excluded. Results: Twenty-one articles with a total of 5630 patients were included. The overall rate of OM was 20.5% and was 23% and 12.2% in supraglottic and glottic tumors, respectively. The OM rate in T1-T2 tumors was 13% and 25% in T3-T4 tumors. T3-T4 tumors had significantly greater odds of developing OM compared to T1-T2 tumors (Odds Ratio [OR] = 2.61, 95% Confidence Interval [CI] = 1.92-3.55, P <.00001). Patients with OM were more likely to develop distant metastasis (OR = 5.65, 95% CI = 3.36-9.51, P <.00001). Conclusions: Patients with advanced T-stage laryngeal SCC should undergo elective neck treatment. More aggressive treatment for patients with history of OM should be considered due to the risk of subsequent regional and distant metastasis. Level of Evidence: II.