Purpose: To study the peculiar characteristics of relapses with long latency following radical treatment for nasopharyngeal carcinoma.
Methods and materials: 847 patients with nasopharyngeal recurrence were retrospectively studied, focusing on the independent effects of latency on different outcome aspects and its relationship with other prognostic factors.
Results: The proportion of recurrence with latency <2 years (Group A), 2-<5 years (Group B), and 25 years (Group C) were 52%, 39%, and 9%, respectively. A higher proportion of Group C originated from patients with node-negative early primary, but fewer of them were still confined within the nasopharynx at detection of recurrence. There was no significant difference in the choice of salvage modality, but among those reirradiated, more of Group C were treated with external beams to a higher dose. The difference in local salvage rate was not statistically significant, but the 5-year distant failure-free rates of the 3 groups were 57%, 67%, and 83%, respectively; and the corresponding disease-specific survival (DSS) were 14%, 20%, and 35%. Multivariate analysis confirmed the independent significance of latency in predicting distant failure (hazard ratio = 0.81 per year, p < 0.01) and cancer deaths (hazard ratio = 0.90 per year, p < 0.01).
Conclusions: Nasopharyngeal recurrence with long latency showed different natural behavior: the prognosis was significantly better due to lower risk of distant failure.