Transoral laser microsurgery for glottic cancer: landmark 24-year single-institution experience with 661 patients and validation of the isoprognostic zone system.

BACKGROUND

Transoral laser microsurgery (TOLMS) is a cornerstone organ-preserving treatment for early and selected intermediate glottic squamous cell carcinoma (LSCC). Prognostic value of infiltration patterns remains underexplored. We evaluated long-term outcomes and validated the isoprognostic zone (IZ) system in a large monocentric cohort.

METHODS

We retrospectively analyzed 661 patients with pT1-pT3 LSCC treated with TOLMS between 2000 and 2024. Endpoints were overall (OS), disease-specific (DSS), disease-free (DFS), laryngectomy-free survival (LFS), laryngeal preservation rate (LPR), and local control with laser alone (LCL). Prognostic factors were assessed with Kaplan-Meier and Cox regression, supported by Weibull accelerated failure time models.

RESULTS

Median follow-up was 64 months. The 5-year LPR was 94.7%, with only 5.3% of patients undergoing total laryngectomy. Both pT stage and IZ independently predicted OS, DSS, DFS, and LFS. High-risk IZ classes were consistently associated with worse survival and laryngeal failure. Positive margins markedly increased recurrence and disease-specific mortality, but timely second-look surgery restored outcomes comparable to margin-negative cases.

CONCLUSIONS

TOLMS provides durable oncologic control and high preservation rates in early to intermediate glottic LSCC. IZ refines prognostication beyond pT, with class VI highlighting anterior commissure infiltration as a decisive risk factor. Prompt second-look surgery is essential to safeguard true laryngeal preservation.