How useful is intraoral ultrasound (US) in the determination of tumor dimensions and margin location of oral tongue carcinoma?
Background: The invasive nature of oral tongue carcinoma tumors into the underlying tongue musculature makes it difficult to assess the deep margin. Tumor thickness (TT) or depth of invasion (DOI) have been widely studied and closely correlate with locoregional recurrence rates and predict occult nodal metastasis. US has been seen as particularly useful in resolving the interface between tongue tumors and the surrounding myo-architecture at the deep margin.
Bottom line: Intraoral ultrasound is useful in the evaluation of oral tongue malignancies when compared with histopathological methods.
Study design: Systematic literature review of 19 articles featuring 678 patients with oral SCC of the tongue.
Setting: PubMed, Embase, and Cochrane databases.
Synopsis: Ultrasonographic tumor thickness (UTT) was the most widely reported metric. Sonographic metrics were compared to a variety of clinical and histopathologic parameters such as histopathologic tumor thickness (HTT), locoregional recurrence, cervical node metastasis rates, margin distance, and survival rates. Ten studies correlated US’s ability to accurately measure TT compared to HTT; eight demonstrated statistically significant correlations. Compared to MRI tumor thickness values, UTT values matched HTT values more closely. Patients with lymph node metastasis had a significantly higher rate of tumors with irregular margin and D-type pattern on US. Studies describing intraoperative US as an adjunct to improve deep margin resection found a clear and statistically significant difference in the deep margin achieved. Variability in optimal cutoff values reported by different groups was an impediment toward a broader application of US for preoperative UTT; however, UTT cutoff points above which significantly higher rates of lymph node metastasis occur include 3, 4, 5, 6, 7, 8, and 11 mm. Limitations included variation in sonographic equipment used, potentially important studies that did not have full-text articles published in English, and varied approaches to statistical analysis and data among articles.
Citation: Tarabichi O, Bulbul M, Kanumuri VV, et. al. Utility of intraoral ultrasound in managing oral tongue squamous cell carcinoma: systematic review. Laryngoscope. 2019;129:662-670.