Abstract
Background: Little is known about the clinical significance of laryngeal cancer as a subsequent tumor. We aimed to determine the impact of a prior cancer history on the prevalence and prognosis of patients with laryngeal cancer. Methods: We retrospectively reviewed patients diagnosed with laryngeal cancer between 2004 and 2011 in the Surveillance, Epidemiology, and End Results (SEER) database. The t-test and chi-squared test were used to compare variables as appropriate. Matched 1:1 case control-adjusted Kaplan-Meier analyses and Cox regression models were performed to investigate the impact of prior cancer on overall survival (OS). Results: Among 20,987 patients with laryngeal cancer, nearly one-fifth (n = 3,915, 18.65%) had a prior cancer. The top three common prior cancers were prostate (588, 28.1%), lung and bronchus (354, 16.9%), and head and neck (306, 14.6%). A total of 73.4% of the prior cancers were diagnosed within 5 years of the laryngeal cancer diagnosis. Compared to patients without prior cancer, a worse survival was significantly associated with a prior cancer among laryngeal cancer patients, regardless of the interval time of the prior cancer (log-rank tests P < 0.001). Furthermore, prior cancer was an independent predictor of worse OS based on the Cox regression model [hazard ratio (HR) = 1.396, 95% confidence interval, 1.336-1.458]. In addition, patients with prior lung and bronchus cancer tended to have the worst survival (log-rank tests P < 0.001). Conclusions: Prior cancer has an adverse effect on clinical outcomes among patients with laryngeal cancer. These results suggest that individualized treatment should be seriously considered in patients with laryngeal cancer and a history of prior cancer, regardless of the interval time of prior cancer.