Survival of patients with head and neck cancer with metachronous multiple primary tumors is surprisingly favorable

BACKGROUND: The objectives of this study are to determine the incidence and survival rate of patients with head and neck squamous cell carcinoma (HNSCC) with multiple primary tumors (MPT) in the HN‐region, lung, or esophagus. METHODS: Patient and tumor specific data of 1372 patients with HNSCC were collected from both the national cancer registry and patient records to ensure high‐quality double‐checked data. RESULTS: The total incidence of MPTs in the HN‐region, lung, and esophagus in patients with HNSCC was 11% (149/1372). Patients with lung MPTs and esophageal MPTs had a significant worse 5‐year survival than patients with HN‐MPTs (29%, 14%, and 67%, respectively, P < 0.001). The 5‐year survival rate for synchronous HN MPTs was only 25%, whereas it was surprisingly high for patients with metachronous HN MPT (85%, P < 0.001). CONCLUSIONS: One of 10 patients with HNSCC develop MPTs in the HN‐region, lung, or esophagus. The 5‐year survival of patients with metachronous HN MPTs was surprisingly favorable.