Abstract
BACKGROUND: Patients with a prior history of cancer are commonly excluded from clinical trial. Increasing number of studies implied that a prior cancer did not adversely affect the clinical outcome among various types of cancer patients. However, the impact of prior cancer on survival of larynx cancer patients remains largely unknown. The aim of this study was to evaluate the prevalence of prior cancer and assess its impact on survival of patients diagnosed with larynx cancer. METHODS: Patients with larynx cancer as the first or second primary malignancy diagnosed from 2004 to 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was conducted to balance baseline characteristics. Kaplan-Meier method, multivariate Cox proportional hazard model, and multivariate competing risk model were performed for survival analysis. RESULTS: A total of 24,812 eligible patients with larynx cancer were included in the study, wherein a total of 2436 patients (9.8%) had a prior history of cancer. Prostate (36%), lung and bronchus (10%), urinary bladder (7%), and breast (6%) were the most common types of prior cancer. A prior cancer history served as a risk factor for overall survival (AHR =1.30; 95% CI [1.21-1.41]; P < 0.001) but a protective factor for cancer-specific mortality (AHR = 0.83; 95% CI [0.72-0.94]; P = 0.004) in comparison with those without prior cancer. The subgroup analysis showed that a prior history of cancer adversely affected overall survival of patients with larynx cancer in most subgroups stratified by timing and types of prior cancer, as well as by different clinicopathologic features. CONCLUSION: Our study indicated an adverse survival impact of a prior history of cancer on patients with larynx cancer. Except for a few particular prior cancer, clinical trials should be considered prudently for laryngeal cancer patients with prior cancers.