Prognostic significance of soft tissue deposits in head and neck squamous cell carcinoma: a systematic review and meta-analysis.

Soft tissue deposits, also known as tumour deposits (TDs), have not been studied well in head and neck squamous cell carcinoma (HNSCC) and are not included in any of the staging systems or treatment guidelines. The aim of this systematic review was to determine the prevalence and prognostic implications of TDs in patients with HNSCC. This systematic review of the literature was conducted following the PRISMA guidelines. The PubMed, Embase, and Scopus electronic databases were searched for relevant studies, from inception to August 2022. Although 14 studies qualified for inclusion, only eight were finally included in the review due to the considerable overlap of patients in several studies. Data from 7127 patients were analysed. The pooled prevalence of TDs was 21% (95% confidence interval (CI) 9-33%). The presence of TDs was adversely associated with overall survival and disease-free survival, with hazard ratios of 2.08 (95% CI 1.60-2.70) and 2.56 (95% CI 1.97-3.32), respectively. TDs are detected in a significant number of patients with HNSCC and adversely affect survival. Longitudinal prospective studies are needed to evaluate the prognostic implications of TDs in HNSCC for their potential role in cancer staging and adjuvant treatment planning.