Comparison of intraoral ultrasound, computed tomography and histopathology in assessment of depth of invasion in buccal mucosa cancers - a cross-sectional study.

PURPOSE: Oral squamous cell carcinoma (OSCC) has high prevalence in this region mainly affecting buccal mucosa in elderly females due to tobacco quid chewing. Depth of invasion (DOI) affects staging, prognosis and treatment outcome. Pre-operative Contrast Enhanced Computed tomography (CECT) and magnetic resonance imaging (MRI) scans are expensive and have limitations in assessing DOI.Buccal mucosa tumors not involving bone can be assessed for DOI by intraoral ultrasound (IOUS).

RESEARCH QUESTION: Is IOUS reliable alternative to CECT in assessing DOI in buccal mucosa cancers?

METHODS

This cross-sectional analytical study compared assessment of DOI using IOUS and CECT in buccal mucosa cancers against gold standard of histopathology in 52 patients with OSCC staged T2 or T3. Sonologist, radiologist assessing CECT and pathologist were blinded against each other's findings. DOI by above methods was compared and correlation analysis between each imaging and histopathology was done.

RESULTS

Out of 52 patients, DOI was same as histopathology in 37 patients (71.2%) by IOUS and in 14 patients (26.9%) by CECT. IOUS over-estimated DOI in 11 (21.1%) patients by 1-2 mm whereas CECT over-estimated DOI in 34 patients (65.4%) by 3-5 mm. DOI was under-estimated in 4 patients (7.1%) each by IOUS and CECT. Correlation coefficient between IOUS and histopathology was 0.929 and that between CECT and histopathology was 0.874 for DOI.

CONCLUSION

IOUS is reliable, easily available tool without ionizing radiation in assessing DOI in OSCC not involving bone.

RESULTS

are encouraging compared to CECT, but it is operator dependent. Multi-institutional, large studies may further validate this conclusion.