Does Anterior Commissure Involvement Matter for Early-Stage Glottic Cancer in the Intensity-Modulated Radiotherapy Era?

Objective: Anterior commissure involvement (ACI) is a negative prognostic factor for local control (LC) in early-stage glottic cancer (ESGC) treated with radiotherapy (RT). However, its impact in the intensity-modulated radiotherapy (IMRT) era remains unclear. This study evaluated the prognostic significance of ACI and its relationship with the RT technique. Materials and Methods: Records of 154 ESGC patients treated with definitive RT between 2000 and 2024 were retrospectively analyzed. Conventional techniques including two-dimensional radiotherapy (2DRT) and three-dimensional conformal radiotherapy (3DCRT) were used in 67% of patients (n = 103), while 33% (n = 51) underwent IMRT. ACI was present in 41% of patients treated with 2DRT/3DCRT and 31% of those treated with IMRT. Results: The cohort included 8% TisN0M0, 60% T1N0M0, and 32% T2N0M0 cases, with a median follow-up of 87 months. The 2- and 5-year local recurrence-free survival (LRFS) rate was 91% and 80%, respectively. The presence of ACI was associated with a significantly lower 5-year LRFS rate in patients treated with 2DRT/3DCRT (71% vs. 90%, p = 0.03), whereas no significant difference was observed among those treated with IMRT (81% vs. 77%, p = 0.13). Conclusion: Although ACI is associated with a poorer LRFS in ESGC patients receiving RT, our findings indicate that the use of IMRT may help alleviate this adverse effect to some extent. These observations warrant further investigation but may have implications for optimizing treatment strategies.