Incidence of and Risk Factors for Mastoiditis after Intensity Modulated Radiotherapy in Nasopharyngeal Carcinoma

PLoS One. 2015 Jun 26;10(6):e0131284. doi: 10.1371/journal.pone.0131284. eCollection 2015.

Abstract

Purpose: To report the incidence of and risk factors for mastoiditis after intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC).

Patients and methods: Retrospective analysis of pretreatment and follow-up magnetic resonance imaging (MRI) data for 451 patients with NPC treated with IMRT at a single institution. The diagnosis of mastoiditis was based on MRI; otomastoid opacification was rated as Grade 0 (none), 1 (mild), 2 (moderate) or 3 (severe) by radiologists blinded to clinical outcome. This study mainly focused on severe mastoiditis; patients were divided into three groups: the G0M (Grade 0 mastoiditis before treatment) group, G1-2M (Grade 1 to 2 mastoiditis before treatment) group and G3M (Grade 3 mastoiditis before treatment) group. The software SAS9.3 program was used to analyze the data.

Results: For the entire cohort, the incidence of Grade 3 mastoiditis was 20% before treatment and 31%, 19% and 17% at 3, 12 and 24 months after radiotherapy, respectively. In the G0M group, the incidence of severe mastoiditis was 0% before treatment and 23%, 15% and 13% at 3, 12 and 24 months after radiotherapy, respectively. Multivariate analysis revealed T category (OR=0.68, 95% CI = 0.469 to 0.984), time (OR=0.668, 95% CI = 0.59 to 0.757) and chemotherapy (OR=0.598, 95% CI = 0.343 to 0.934) were independent factors associated with severe mastoiditis in the G0M group after treatment.

Conclusions: Mastoiditis, as diagnosed by MRI, occurs as a progressive process that regresses and resolves over time in patients with NPC treated using IMRT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Carcinoma
  • Female
  • Humans
  • Incidence
  • Male
  • Mastoiditis / epidemiology*
  • Mastoiditis / etiology
  • Middle Aged
  • Nasopharyngeal Carcinoma
  • Nasopharyngeal Neoplasms / epidemiology*
  • Nasopharyngeal Neoplasms / radiotherapy*
  • Radiation Injuries / epidemiology*
  • Radiotherapy, Intensity-Modulated / adverse effects*
  • Risk Factors

Grants and funding

This work was supported by grants from the National Natural Science Foundation of China (No. 81372409), the Sun Yat-Sen University Clinical Research 5010 Program (No. 2012011), the Natural Science Foundation of Guangdong Province (No. S2013010012220), the Science and Technology project of Guangzhou City, China (No. 132000507), the Health & Medical Collaborative Innovation Project of Guangzhou City, China (201400000001), and the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (2014BAI09B10). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.