(A591) Oral tongue cancer: Comparative correlation of radiological modalities with pathology

Introduction: Oral cancers constitute 30% of head neck cancers in the Indian subcontinent. Oral tongue subsite is generally associated with aggressive biological behavior. Depth of invasion (DOI) is highly predictive of regional/distant metastases and survival. Tumor thickness (TT), the surrogate of DOI preoperatively, can be determined by cross-sectional radiology. However, modalities utilized for estimation of this important parameter may not be uniformly accurate, and utilization varies widely based on resource availability and cost.
We aimed to establish and compare concordance of two radiological modalities - computed tomography (CT) and magnetic resonance imaging (MRI) with preoperatively estimated TT, and TT / DOI on histopathology. This would aid accurate staging and counseling for planned adjuvant therapy.

Methods: This is a retrospective study of 135 patients with squamous cell carcinoma (SCC) of the oral tongue diagnosed between Oct 2019 and Sep 2022, who underwent preoperative staging CT or MR of the oral cavity. The radiological TT was correlated with actually measured DOI and TT on the histopathology specimen for each patient. In view of anticipated ex vivo shrinkage of the tumor specimen, discordance of up to 30 percent was considered acceptable. Statistical analysis was by descriptive means and Chi square analysis.

Results: Median age was 59 years, Male: female ratio 14:1. Stage distribution: I 10.3%, II 28.1%, III 26.6%, IV 34.8%. CT or MR with contrast were utilized for preoperative T staging in 66 and 69 patients respectively. Concordance was found in 76 percent of the entire patient study group. Discordance between the two imaging modalities was not statistically significant (p=0.14).

Conclusions: Both CT and MR have comparable and acceptable concordance rates in assessment of TT and prediction of DOI in oral tongue SCC. These could potentially aid pre-operative prognostication and pre-emptive counseling for adjuvant therapy. Further studies with larger numbers are mandated to further explore this association.