Prognostic value of prevertebral space involvement in nasopharyngeal carcinoma based on intensity-modulated radiotherapy

Int J Radiat Oncol Biol Phys. 2012 Mar 1;82(3):1090-7. doi: 10.1016/j.ijrobp.2010.11.063. Epub 2011 Aug 22.

Abstract

Purpose: To investigate the prognostic significance of prevertebral space involvement (PSI) in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT).

Methods and materials: A retrospective review of data from 506 biopsy-proven, nonmetastatic NPCs was performed. Patients underwent magnetic resonance imaging examinations and received IMRT as their primary treatment.

Results: In this series, 161 NPC patients (31.8%) had PSI. Parapharyngeal space (p < 0.001), skull base (p < 0.001), and paranasal sinuses (p = 0.009) were associated with PSI after multivariate analysis. The 4-year overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS) for NPC patients with and without PSI was 69.1% and 89.2% (p < 0.0001), 83.9% and 96.4% (p < 0.0001), and 71.6% and 89.6% (p < 0.0001), respectively. Multivariate analysis identified PSI as an independent negative prognostic factor for both OS (HR = 1.478-4.380; p = 0.001) and DMFS (HR = 1.389-4.174; p = 0.002). Patients with PSI had similar survival rates in OS and DMFS (p = 0.241 and p = 0.493, respectively) to that of T4 disease, while the differences between PSI and T3 disease in both OS and DMFS were distinctly significant (p = 0.029 and p = 0.029, respectively).

Conclusions: For NPC patients treated with IMRT, PSI was found to be an independent prognostic factor for both OS and DMFS. It seems reasonable that PSI should be classified as a T4 disease on the basis of the current American Joint Committee on Cancer staging classification criteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / pathology
  • Adolescent
  • Adult
  • Aged
  • Analysis of Variance
  • Carcinoma
  • Cervical Vertebrae / pathology
  • Female
  • Humans
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Nasopharyngeal Carcinoma
  • Nasopharyngeal Neoplasms / drug therapy
  • Nasopharyngeal Neoplasms / mortality
  • Nasopharyngeal Neoplasms / pathology
  • Nasopharyngeal Neoplasms / radiotherapy*
  • Neoplasm Invasiveness
  • Neoplasm Staging
  • Prognosis
  • Radiotherapy, Intensity-Modulated*
  • Retrospective Studies
  • Tumor Burden
  • Young Adult