Addition of Chemotherapy Is Associated With Decreased Survival in Early-Stage (T1-2N0M0) Glottic Squamous Cell Carcinoma Treated With Definitive Radiotherapy.

Abstract

The role of chemoradiation (CRT) in treating patients with early-stage glottic squamous cell carcinoma (SCC), especially for T2N0M0 glottic SCC with impaired vocal cord mobility, remains unexplored. We sought to evaluate the impact of CRT on survival in early-stage glottic SCC by using the SEER database. We included patients with localized (T1-4N0M0) glottic SCC (N = 4,743) diagnosed between 2004 and 2014 and treated with definitive radiotherapy (RT) alone, CRT, or laryngectomy alone in the SEER database. Disease-specific mortality (DSM) was evaluated via multivariable regression using a competing risk model that accounts for other-cause mortality as a competing risk event for DSM. One-to-one propensity score matching between CRT and RT cohorts was also performed to facilitate comparison of cumulative DSM and other-cause mortality incidences stratified by T stage. After stratification by T stage, CRT was associated with increased DSM in T1-2N0M0 glottic SCC (adjusted hazard ratios [AHRs], 4.222 and 2.260 for T1 and T2 disease, respectively; P < .001 for both). For T2N0M0 glottic SCC with and without impaired vocal cord mobility, CRT resulted in significantly increased DSM compared with RT alone in both cohorts (AHR, 2.084; P = .046 and AHR, 2.412; P < .001, respectively). After propensity score matching, cumulative incidence plots demonstrated a statistically significant increase in DSM associated with CRT compared with RT alone for both T1 and T2 glottic SCC (P < .001 and P = .003, respectively). CRT for T1-2N0M0 glottic SCC was associated with increased DSM compared with RT alone. This pattern persisted upon further stratification on the basis of vocal cord mobility status for T2N0M0 glottic SCC. This finding warrants careful consideration of chemotherapy in early-stage glottic SCC.