Preoperative computed tomography for assessment of bone invasion in oral squamous cell carcinoma: diagnostic accuracy and anatomical subsite dependency

PURPOSE: Accurate preoperative assessment of bone invasion is crucial in oral squamous cell carcinoma (OSCC), because it directly influences staging and surgical planning. Computed tomography (CT) is widely used, but its diagnostic performance may vary with tumor localization and image quality. METHODS: In this retrospective study, patients with OSCC who underwent preoperative CT imaging and subsequent surgical resection with histopathological evaluation were identified. Bone invasion was assessed on CT using a graded and dichotomous classification. Histopathology served as reference standard. Diagnostic performance was analyzed overall and stratified by tumor localization, radiological severity, and image quality. RESULTS: 572 patients were included. Histologically confirmed bone invasion was present in 134 cases (23.6%). Overall, CT demonstrated a sensitivity of 63.4% and a specificity of 90.8%, with an overall diagnostic accuracy of 84.3%. The probability of bone invasion increased stepwise with increasing radiological severity (p < 0.001). Diagnostic performance varied by tumor localization, with significant differences in specificity and overall accuracy (p < 0.001), while sensitivity did not differ significantly (p = 0.597). Radiological grading correlated with pathological stage; nevertheless, 12.3% of pT2 tumors were interpreted as showing bone involvement, while 36.6% of histologically confirmed pT4 tumors remained radiologically occult. Exclusion of cases with relevant imaging artifacts resulted in improved diagnostic performance (AUC 0.80 vs. 0.78). CONCLUSION: Preoperative CT provides clinically relevant information for assessing bone invasion in OSCC. However, diagnostic performance varies across anatomical subsites, as well as radiological severity and image quality. A localization-aware interpretation may help to avoid under- and overtreatment.