PLoS ONE (Jan 2014)

Endoscope-guided interstitial intensity-modulated brachytherapy and intracavitary brachytherapy as boost radiation for primary early T stage nasopharyngeal carcinoma.

  • Xiang-Bo Wan,
  • Rou Jiang,
  • Fang-Yun Xie,
  • Zhen-Yu Qi,
  • Ai-Ju Li,
  • Wei-Jun Ye,
  • Yi-Jun Hua,
  • Yu-Liang Zhu,
  • Xiong Zou,
  • Ling Guo,
  • Hai-Qiang Mai,
  • Xiang Guo,
  • Ming-Huang Hong,
  • Ming-Yuan Chen

DOI
https://doi.org/10.1371/journal.pone.0090048
Journal volume & issue
Vol. 9, no. 3
p. e90048

Abstract

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BACKGROUND: Intracavitary brachytherapy (ICBT) is usually applied as boost radiotherapy for superficial residual of nasopharyngeal carcinoma (NPC) after primary extern-beam radiptherapy (ERT). Here, we evaluated the outcome of endoscope-guided interstitial intensity-modulated brachytherapy (IMBT) boost radiation for deep-seated residual NPC. METHODOLOGY/PRINCIPAL FINDINGS: Two hundred and thirteen patients with residual NPC who were salvaged with brachytherapy boost radiation during 2005-2009 were analyzed retrospectively. Among these patients, 171 patients had superficial residual NPC (≤1 cm below the nasopharyngeal epithelium) were treated with ICBT boost radiation, and interstitial IMBT boost radiation was delivered to 42 patients with deep-seated residual NPC (>1 cm below the nasopharyngeal epithelium). We found that IMBT boost subgroup had a higher ratio of T2b (81.0% VS 34.5%, P<0.001) and stage II (90.5% VS 61.4%, P = 0.001) than that of ICBT boost subgroup. The dosage of external-beam radiotherapy in the nasopharyngeal (63.0±3.8 VS 62.6±4.3 Gray (Gy), P = 0.67) and regional lymph nodes (55.8±5.0 VS 57.5±5.7 Gy, P = 0.11) was comparable in both groups. For brachytherapy, IMBT subgroup had a lower boost radiation dosage than ICBT subgroup (11.0±2.9 VS 14.8±3.2 Gy, P<0.01). Though the IMBT group had deeper residual tumors and received lower boost radiation dosages, both subgroups had the similar 5-year actuarial overall survival rate (IMBT VS ICBT group: 96.8% VS 93.6%, P = 0.87), progression-free survival rate (92.4% VS 86.5%, P = 0.41) and distant metastasis-free survival rate (94.9% VS 92.7%, P = 0.64). Moreover, IMBT boost radiation subgroup had a similar local (97.4% VS 94.4%, P = 0.57) and regional (95.0% VS 97.2%, P = 0.34) control to ICBT subgroup. The acute and late toxicities rates were comparable between the both subgroups. CONCLUSIONS/SIGNIFICANCE: IMBT boost radiation may be a promising therapeutic selection for deep-seated residual NPC.