Clinical Characteristics and Predictive Outcomes of Recurrent Nasopharyngeal Carcinoma—A Lingering Pitfall of the Long Latency

SIMPLE SUMMARY: Unlike other head and neck cancers, nasopharyngeal carcinoma (NPC) with long-latent recurrence (>five years) is not rare. This study aims to investigate the clinical characteristics and outcomes of long-latent recurrent NPC. We found that 8.1% recurrence occurred after five years. About two thirds of these patients’ primary cancer belonged to the early stages, and almost half of the recurrence was a local recurrence. The five-year overall survival and disease-specific survival rate of long-latent recurrence was 19.7% and 24.5%, respectively. Most long-latent local recurrence was found in unresectable rT3 or rT4 cases, while one-third could not be detected by endoscopy due to recurrence in the skull base. A higher percentage of patients who died after long-latent recurrence were symptomatic with a follow-up interval more than six months, reflecting that delayed detection of recurrence may have a great impact on survival outcome. A long-term follow-up is necessary for early detection of NPC recurrence even after five years of disease-free interval. ABSTRACT: Purpose: To investigate the clinical characteristics, risk factors, and clinical outcomes of long-latent recurrence (>five years) of nasopharyngeal carcinoma (NPC). Methods: This retrospective study enrolled newly diagnosed NPC patients from the Chang Gung Research Database between January 2007 and December 2019. We analyzed the patients’ characteristics and survival outcomes after recurrence. Results: A total of 2599 NPC patients were enrolled. The overall recurrence rate was 20.5%, while 8.1% of patients had long-latent recurrence (>five years). These patients had a higher percentage of initial AJCC (The American Joint Committee on Cancer) stage I/II (60.5%, p = 0.001) and local recurrence (46.5%, p < 0.001). Unresectable rT3 and rT4 were found in 60% of patients when recurrence and 30% of local recurrence occurred in the skull base, which could not be detected by the regular endoscopy. The five-year overall survival rate of long-latent recurrence was 19.7%. Alive patients tended to be asymptomatic but have regular follow-ups with the interval less than six months. Multivariate analysis showed age and initial advanced AJCC stages were independent risk factors of death after recurrence. In contrast, patients with recurrence between two and five years, salvage surgeries, and regional recurrence had favorable survival outcomes. Conclusion: Long-latent NPC recurrence is not rare, and the survival outcome is poor. Regular follow-up for early detection of NPC recurrence is necessary even after five years of disease-free period.