Partial vs Whole Laryngeal Radiotherapy for Clinical Stage T1-2N0M0/Tis Laryngeal Carcinoma.

Importance: The current standard treatment for clinical tumor stage 1 to 2 or in situ laryngeal carcinoma without node involvement or metastases (T1-2N0M0/Tis) is whole laryngeal radiotherapy (WLRT), whereas microsurgery typically resects only the tumor-involving vocal cord with a narrow margin. Clinical outcomes of partial laryngeal radiotherapy (PLRT) have not been quantified. Objective: To compare the effectiveness and toxic effects of PLRT vs WLRT in patients with clinical stage T1-2N0/Tis laryngeal carcinoma. Design, Setting, and Participants: This was a single-institution retrospective cohort study of patients with clinical stage T1-2N0M0/Tis squamous cell carcinoma of the larynx who underwent intensity-modulated RT from January 2013 to December 2024. Data were analyzed from January to February 2025. Main Outcomes and Measures: Long-term locoregional control, laryngectomy-free survival, distant metastasis, and overall toxic effects. Acute and late radiation toxic effects were graded using Common Terminology Criteria for Adverse Events, version 4.0. Patient-reported swallowing-related quality of life (MD Anderson Dysphagia Inventory) was collected at each visit when feasible. Results: The analyses included 233 consecutive patients with T1-2N0M0/Tis squamous cell carcinoma of the larynx who were treated with intensity modulated radiotherapy (176 with WLRT vs 57 with PLRT). The median (IQR) follow-up in the WLRT group was 60 (28-87) months, and in the PLRT group, 31 (16-64) months. The largest tumor stage-related difference in WLRT was observed in T1b (100%) and Tis (50%) disease, with an absolute difference of 50% (95% CI, 25.4% to 73.2%). There were no important clinical differences between PLRT and WLRT in 3-year locoregional control rates (85.4% vs 90.8%; rate difference, -5.4%; 95% CI, -13.5% to 6.9%), laryngectomy-free survival (93.2% vs 94%; rate difference, -0.8%; 95% CI, -9.1% to 7.5%), distant metastasis-free survival (100% vs 97.6%; rate difference, 2.4%; 95% CI, -0.3% to 4.9%), and overall survival (91.4% vs 88.9%; rate difference, 2.5%; 95% CI, -6.8% to 12.8%). There was no contralateral vocal-fold failure in the PLRT group. There was a large difference in the 3-year locoregional control in T2 tumors between the WLRT (85.1%) and PLRT groups (66.7%), with a difference of 18.4% (95% CI, -5.8% to 21.3%). The incidence of acute dysphagia was lower in the PLRT than in the WLRT group (73.7% vs 92.6%; difference, 18.9%; 95% CI, 6.9% to 30.9%). Median composite scores on the MD Anderson Dysphagia Inventory at 3 and 6 months postradiotherapy were higher in the PLRT group (86 vs 77; difference, 8; 95% CI, 2 to 14; and 96 vs 81; difference, 4; 95% CI, -2 to 8; respectively), although the observed differences may not be clinically important. Conclusions and Relevance: This cohort study found that there were no clinically important differences observed in locoregional control between PLRT and WLRT; however, PLRT may be associated with lower rates of acute toxic effects compared to WLRT. Wide confidence intervals across all end points indicated substantial uncertainty regarding comparative effectiveness. The shorter median follow-up time in the PLRT group limited evaluation of late toxic effects and long-term tumor control outcomes; together with the lack of adjustment for confounding factors, this study underscores the need for further evaluation of PLRT.