A Comparison of the Prognosis Between Juvenile and Adult Nasopharyngeal Carcinoma: A Propensity Score Matching Study

Abstract

To investigate whether the juvenile patients with nasopharyngeal carcinoma (NPC) in China have better prognosis than the adult patients under the control of multiple variables, so as to provide a reference for the clinical treatment of juvenile NPC. 1139 newly diagnosed NPC patients without metastasis in our hospital were retrospectively collected. All patients were treated with intensity-modulated radiation therapy (IMRT), of which 60 cases were the juvenile (≤ 18 years old) between January 2003 and December 2018, and the remaining 1079 cases were the adult (≤ 65 years old) between January 2013 and December 2014. The median follow-up time was 83.6 months (6.8-190.2 months) and 61.1 months (4.5-84.3 months), respectively. To reduce selection and confounding bias, 1:2 propensity score matching (PSM) was used. Overall Survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and local relapse-free survival (LRFS) were estimated by Kaplan-Meier method and compared by the Log-rank test. The long-term toxicity of children and adolescents was evaluated according to the criteria of the Radiation Therapy Oncology Group (RTOG), the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and Late Effects Normal Tissue Task Force-Subjective, Objective, Management and Analytic (LENT-SOMA) scoring systems. The 5-year OS of the juvenile and adults were 88.07% and 85.08%, respectively. Before matching, the LRFS of the juvenile was significantly better than that of the adult (P = 0.039), but no significant difference was found in OS, DFS and DMFS, respectively (all P>0.05). After using a PSM, the DMFS was still found to be of no significant difference between the two groups, whereas the OS, DFS, and LRFS of the juvenile were markedly higher than that of the adult (P = 0.005, P = 0.035, and P = 0.023), respectively. With regard to the long-term toxicity of 53 alive juvenile patients, the common sequelae were cervix fibrosis, ototoxicity and xerostomia (20.75%, 20.75% and 18.87%). However, except for two patients developing grade 3 ototoxicity, all of the sequelae were within grade 2, and no degree 4 sequelae occurred. Using a PSM method, the juvenile with NPC had better 5-year OS, DFS and LRFS than the adult patients, which provides the first Chinese data with positive results in the IMRT era. In addition, as the sole grade 3 complication among the common late toxicities, ototoxicity was the most concerning problem which could have a negative impact on the quality of life. Therefore, how to reasonably lower the radiation dose to protect adjacent organs in juvenile NPC was deserved to be further explored.