Prevalence of occult nodal metastases in squamous cell carcinoma of the temporal bone: a systematic review and meta-analysis

Purpose: Primary: To determine the rate of occult cervical metastases in primary temporal bone squamous cell carcinomas (TBSSC). Secondary: to perform a subgroup meta-analysis of the risk of occult metastases based on the clinical stage of the tumour and its risk based on corresponding levels of the neck. Methods: A systematic review and meta-analysis of papers searched through Medline, Cochrane, Embase, Scopus and Web of Science up to November 2021 to determine the pooled rate of occult lymph node/parotid metastases. Quality assessment of the included studies was assessed through the Newcastle-Ottawa scale. Results: Overall, 13 out of 3301 screened studies met the inclusion criteria, for a total of 1120 patients of which 550 had TBSCC. Out of the 267 patients who underwent a neck dissection, 33 had positive lymph nodes giving a pooled rate of occult metastases of 14% (95% CI 10-19%). Occult metastases rate varied according to Modified Pittsburg staging system, being 0% (0-16%) among 12 pT1, 7% (2-20%) among 43 pT2 cases, 21% (11-38%) among 45 pT3, and 18% (11-27%) among 102 pT4 cases. Data available showed that most of the positive nodes were in Level II. Conclusion: The rate of occult cervical metastases in TBSCC increases with pathological T category with majority of nodal disease found in level II of the neck.