The role of Radiation for Recurrent Laryngeal Carcinoma in Situ compared to First Line Radiotherapy

Document Type

Conference Proceeding

Publication Date

10-1-2024

Publication Title

American Journal of Clinical Oncology-Cancer Clinical Trials

Abstract

Background: Laryngeal carcinoma in situ (CIS) is a common premalignant condition with a risk for multiple recurrences and progression to invasive laryngeal squamous cell carcinoma (SCC). Objectives: We explored the impact of radiotherapy (RT) on outcomes for laryngeal CIS in the first line compared to recurrent cases. Methods: We queried our in-house Head and Neck Cancer database for laryngeal CIS patients treated between 6/2001 and 12/2021. We excluded low-grade dysplasia, CIS with synchronous invasive SCC or metachronous SCC within 3 months of the initial CIS biopsy and cases with inadequate follow up. Patients initially received either definitive RT or other modalities (CO2/KTP transoral laser ablation, PDT or surgery: transoral endoscopic excision/stripping). After 1st line treatment, follow-up includes visits every 3-6 months with laryngoscopy and biopsies as appropriate. For recurrent cases (CIS > 6 months of 1st line treatment), salvage therapies received, and long-term outcomes were reported. We investigated post-RT CIS recurrence free (RFS), invasive SCC free (IFS) and disease free (DFS) survival for patients managed with 1st line RT vs those who received 2nd line RT after recurrence using Kaplan-Meier curves and log rank test. We also compared long term outcomes for RT vs non-RT modalities. Results: 85 CIS cases were included: median age 65 years (IQR: 55-74), 73 males (85%) and 70 white (82.4%). 86% had a history of smoking with median pack year of 38 (IQR: 20-55) and 66% had a history of alcohol use. CIS was glottic in most of the cases (90.6%: 66% unilateral, 21% bilateral & 13% involved anterior commissure); with only 9.4% in the supraglottic region. RT was used in 49.4% (n=42) with median dose of 63 Gy/28 fractions, mainly by 3D conformal RT (76%). Non-RT modalities, 50.6% (n=43): surgery alone (46.5%), CO2/KTP laser (32.6%) or PDT (20.9%). RT and non-RT patients were well-balanced except for Charlson comorbidity index: median 2 (IQR 1-3) in non-RT vs 1 (IQR 0-2) in RT; p= 0.007. After a median follow-up of 4.8 years (IQR 3.5), only 4 cases (9.5%) of RT treated cases had CIS recurrences compared to 31 cases (72.1%) for nonRT candidates of whom 12 cases (34%) received 2nd line RT (Figure 1). After RT, 2nd line RT recipients had non-significantly different 2-year-RFS (100% vs 95.1% (88.8-100), IFS (89% (80-100) vs 81% (60-100)) and DFS (84% (72-97) vs 81% (60-100)) compared to 1st line RT (p >0.05 for all); and this was maintained at 5-years. Overall, IFS and overall survival and were non-different among all treatment modalities and all CIS recurrences were successfully salvaged with ultimate RFS of 100%. Conclusions: Laryngeal CIS can be treated with a wide range of modalities including RT which has better recurrence free survival. Non-RT treatments were more commonly used with frail patients with higher comorbidities and can be salvaged successfully with many options including RT with equivalent long-term results. Images: Laryngeal CIS cases classified by 1st line of treatment showing outcomes and treatment of CIS recurrences with long-term survival.

Volume

47

Issue

10

First Page

S7

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