Treatment Outcomes in Patients with Carcinoma In Situ of the Larynx

Objective To compare survival endpoints in patients with laryngeal carcinoma in situ (L‐CIS) who received definitive radiotherapy (RT) versus other modalities as first‐line treatment and after disease recurrence. Methods This is a retrospective study of patients with L‐CIS treated between June 2001 and December 2021. Survival outcomes (recurrence‐free (RFS), invasion‐free (IFS), laryngectomy‐free (LFS), and overall survival (OS)) were compared between patients who had first‐line RT versus non‐RT modalities and for patients with recurrent disease who underwent second‐line RT. Results A total of 85 patients with L‐CIS were included (73 men [85.9%] and 12 [14.1%] women, median age of 65 [IQR: 55–74] years). Of these, 42 had first‐line RT (49.4%) and 43 (50.6%) had non‐RT treatment. After median follow‐up of 4.8 (IQR: 2.8–9) years, patients in the first‐line RT group had improved 2‐year (94.2% [95% confidence interval (CI): 86.7–100] versus 41.7% [CI: 29.3–59.5]) and 5‐year (90.6% [CI: 80.9–100] versus 27.5% [CI: 16.4–48.2]) RFS relative to non‐RT recipients ( p < 0.001). OS and IFS were similar between groups. However, patients in the RT group had worse 2‐year (94% [CI: 87–100] versus 98% [CI: 93–100]) and 5‐year (82% [CI: 68–99] versus 98% [CI: 93–100]; p = 0.013) LFS. All 35 patients with recurrent L‐CIS were successfully cured with second‐line treatments (12 received RT [34.3%]), and no differences in any survival endpoints were seen in these patients based on first‐line and second‐line treatments. Conclusion Although first‐line RT for L‐CIS led to improved recurrence‐free survival compared with other modalities, second‐line RT may be a particularly valuable option for recurrent CIS. Level of Evidence 3 Laryngoscope , 135:779–786, 2025