Thyroid cartilage invasion in early-stage squamous cell carcinoma involving the anterior commissure

Background Anterior commissure (AC) carcinoma is in close proximity to the thyroid cartilage. Our objective was to evaluate risk factors for thyroid cartilage invasion. Methods This was a retrospective study of tumors involving the AC treated by open surgery. Tumor stage, extensions, vocal fold (VF) mobility, CT scan, and pathologic cartilage status were recorded. Results Ninety-four patients with clinical T (cT) classifications cT1b (44%), cT2 (50%), and cT3 (6%) were included. The incidence of thyroid cartilage invasion was 8.5%, significantly related to VF mobility, with invasion in 31% versus 5% with normal mobility (p =.002). Sensitivity, specificity, and positive and negative predictive values for decreased VF mobility were 50%, 90%, 31%, and 95%, respectively. After a median follow-up of 49 months, there was no difference in local control between tumors with or without cartilage invasion. Conclusions For these tumors involving the AC, VF mobility was the only significant factor related to thyroid cartilage invasion and should be taken into consideration when planning surgery.