Global Annualized Recurrence Rates and Dynamic Risk Profiles in Head and Neck Cancer.

Recurrence limits survival in head and neck cancer (HNC), yet its annualized rate remains poorly defined due to heterogeneous follow-up durations across studies. In this systematic review and meta-analysis, we searched four databases from inception to May 1, 2025, and included 1060 studies comprising 336,615 patients and 1.40 million person-years of follow-up. Using person-time analysis, we estimated a global recurrence rate of 6.57 per 100 person-years (95% CI, 6.28-6.87). Recurrence rates varied substantially across settings, with higher rates observed in lower-middle-income countries (10.16 per 100 person-years) and in hypopharyngeal cancers (14.11 per 100 person-years). Median follow-up duration explained the largest share of between-study heterogeneity (R2 = 37.12%), and studies with shorter reported follow-up tended to show higher annualized recurrence rates. Substantial differences in recurrence rates were noted when stratified by clinical and biological factors. Notably, the prognostic impact of patient age and tumor stage was time-dependent, being most pronounced in the early post-treatment period and attenuating over time. Patients with recurrent disease faced a high mortality risk, with a pooled case fatality rate of 55.80% (95% CI, 51.20-60.30). These findings quantify a high global recurrence rate of HNC with pronounced time dependence, informing risk-adapted surveillance strategies and early, histology-specific prevention to reduce recurrence-related mortality.