Impact of treatment modality on survival in patients with stage IV laryngeal cancer: A population-based propensity score analysis

Abstract

Introduction: The treatment of advanced stage laryngeal suffered a major shift away from surgery and towards larynx-preservation alternatives after the publication of major clinical trials. But its applicability in real-world situations is not consensual.

Materials and methods: We reviewed a population-based database from Brazil regarding patients treated for laryngeal cancer and selected those with stage IV disease at presentation. Survival analysis was realized by the Cox proportional hazards method and propensity scores were used to compensate for non-random allocation to different treatment arms.

Results: A total of 5577 patients were included in the analyses, with 4243 staged as CS IVa, 1010 as CS IVb and 324 as CS IVc. In univariate and multivariate analysis, gender, cT stage, cN stage, cM stage and treatment modality were significant predictors of disease-specific survival. In patients with CS IVa, age, gender, payment modality, location within the larynx, cT and cN stages and treatment modality were significant. After propensity score adjustment, treatment modality remained significant, favoring primary surgery with disease-specific survival (HR: 0.5041, 95% CI: 0.4494-0.5644, p < 0.001) and overall survival (HR: 0.5485, 95% CI: 0.4955-0.6072, p < 0.001) as outcomes of interest. Patients staged as cT4a cN0 were selected and analyzed as a distinct subset. In multivariate analysis, treatment modality was the only variable with significant prognostic impact with improved outcome for surgery-based treatment (HR: 2.521, 95% CI: 1.897-3.350, p < 0.001).

Conclusions: The extrapolation of clinical trials to the real-world facilities must be carefully weighted. The setting of trial conduction may influence its outcome and may not be reproducible. Our results show that patient selection and the facilities of clinical trials may play a significant role in the success of non-surgical approaches to non-metastatic stage IV laryngeal cancer.

Keywords: Epidemiology; Laryngeal cancer; Prognosis; Propensity score; Radiotherapy; Surgery.