Impact of second primary esophageal or lung cancer on survival of patients with head and neck cancer

Second cancers following head and neck cancer (HNC) most often involve the esophagus and lung, yet the actual magnitude of impact of second primary esophageal or lung cancer on survival of HNC patients has not been well established, particularly by a large-scale epidemiological study. To provide a quantitative estimate of the survival impact, we conducted a population-based study including 63,720 cases of HNC subsets, of which 3658 developed at least one second primary malignancy, 253 had a second esophageal cancer and 388 had a second lung cancer. A Cox proportional hazards model which included age at initial cancer diagnosis and gender were employed to compare the survival rates between patients with different types of second cancers. Our results showed that the second esophageal or lung cancer contributed to a poorer outcome than the other types of second cancer, regardless of the index tumor site (all Ps⩽0.019). The overall median survival was 0.76±0.04 and 0.72±0.08years for second esophageal and lung cancers, respectively. Compared to those without second cancers, the patients with second esophageal or lung cancer were associated with a significant reduction in survival, with an estimated 31–105% excess risk of death according to the site of the primary index tumor. In conclusion, the second esophageal and lung cancers have a significantly negative impact on the survival of HNC patients, thereby calling for a more effective program for surveillance and chemoprevention for these two sites.