Currently, there is little evidence supporting the use of early endpoints to assess primary treatment outcomes in nasopharyngeal carcinoma (NPC). We aim to explore the relationship between 24-month progression-free survival (PFS24) and subsequent overall survival (sOS) as well as loss of lifetime (LoL) in NPC patients. sOS is defined as survival from the 24-month point or progression within 24 months leading to mortality. LoL represents the reduction in life expectancy due to NPC, compared to the general population matched by age, sex, and calendar year. The standardized mortality ratio (SMR) is defined as the ratio of observed mortality to expected mortality. The study included 6315 patients from nonendemic and endemic regions of China. Among them, 5301 patients (83.9%) achieved PFS24, with a 5-year sOS of 90.2% and an SMR of 1.0. Over a 10-year period following treatment, the mean LoL was only 0.01 months/year. For most subgroups, patients achieving PFS24 exhibited comparable sOS and LoL with the general population. However, patients failing to achieve PFS24 showed significantly worse outcomes, with 5-year sOS of 21.9%, SMR of 23.7, and LoL of 6.48 months/year. These notable outcome disparities highlight the importance of PFS24 in NPC risk stratification, patient monitoring, and study design.