Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Kaplan-Meier survival curves for the four calendar periods in the study population. Overall survival (OS) (A), progression-free survival (PFS) (B), locoregional relapse-free survival (LRFS) (C), and distant metastasis-free survival (DMFS) (D) compared across the entire cohort of stage II nasopharyngeal carcinoma patients. p-values were calculated using the unadjusted log-rank test.
