Secondary primary cancer in patients with head and neck carcinoma: the differences among hypopharyngeal, laryngeal, and other sites of head and neck cancer.

This paper presents a population-based retrospective cohort study to identify the differences in secondary primary cancer ( SPC) among hypopharyngeal, laryngeal, and other sites of head and neck cancer ( HNC). Data were collected from the Taiwan National Health Insurance Research Database ( NHIRD) for the period 1979-2010. The study cohort comprised 5914 newly diagnosed hypopharyngeal and laryngeal patients from the registry of the Catastrophic Illness Patients Database ( CIPD). The comparison cohort comprised 5914 patients with other sites of HNC. We used a multivariate Cox proportional-hazards regression model to assess the risk of developing SPC. The incidence of SPC in the study cohort was 68% higher compared with the comparison cohort (23.9 vs. 14.2 per 1000 person-years, Incident Rate Ratio = 1.68). The study cohort had a higher adjusted hazard ratio ( HR) in oesophageal cancer ( HR = 3.47) and lung cancer ( HR = 1.89). The difference in SPC incidence between the study and comparison cohort was significant. [ABSTRACT FROM AUTHOR]