Pattern of Failure in Nasopharyngeal Carcinoma After Radiotherapy in a Low‐Incidence Population: A DAHANCA Study

BACKGROUND: Nasopharyngeal carcinoma (NPC) is uncommon in many populations. Most existing clinical evidence comes from endemic areas, where Epstein-Barr virus (EBV)-associated subtypes predominate. We analyzed patterns of failure in a population-based cohort from Denmark, a low-incidence setting. METHODS: Patients with NPC treated with curative intent between 2000 and 2018 were identified through the Danish Head and Neck Cancer Study Group (DAHANCA) database and subsequently validated. RESULTS: We identified 331 patients. The 5-year cumulative incidence of failure was 31.1% for any failure, 16.9% for locoregional failure, and 14.2% for distant failure. Distant failure occurred almost exclusively in locally advanced disease (Stage I: 0%; II: 4.2%; III: 21.1%; and IVa: 19.4%). Rates of any failure were comparable between EBV-positive (29.7%) and EBV-negative (32.0%) tumors. CONCLUSIONS: In this low-incidence population, the likelihood of failure after primary radiotherapy for NPC did not differ by EBV status. Distant failure was largely confined to patients with locally advanced stages.