A nationwide population-based study to access the risk of metachronous esophageal cancers in head and neck cancer survivors.

How long esophageal screening should be performed for, and on which sub-groups of head and neck cancer (HNC) survivors, remains uncertain. This retrospective study analyzed data from the Taiwan National Health Insurance Research Database from 1999 to 2013. A total of 68,131 newly- diagnosed HNC patients were enrolled. Subjects who received esophageal endoscopic screening within 6 months after their diagnosis date of index HNC were identified. The incidence trends of secondary primary EC were analyzed using a Cochran-Armitage trend test. Among the 9,707 patients who received index esophageal endoscopy screening, 101 (1.0%) cases of synchronous EC were diagnosed. The 5- and 10-year cumulative incidence rates of metachronous ECs were 1.4% and 2.7%, respectively in those with an initial negative index endoscopic finding. Patients with oropharynx or hypopharynx cancers were at significantly higher risk of developing metachronous ECs compared with those with oral or larynx cancers (10-year incidence rate: 3.3% vs. 0.9%, respectively; hazard ratio: 2.15; 95% confidence intervals: 1.57-2.96). Metachronous EC continues to develop in patients with HNC even at 10-years after treatment for primary HNC. HNC patients, especially those with oropharynx or hypopharynx cancer, may require long-term endoscopic surveillance.