%0 Journal Article %T Endoscope-Guided Interstitial Intensity-Modulated Brachytherapy and Intracavitary Brachytherapy as Boost Radiation for Primary Early T Stage Nasopharyngeal Carcinoma %A Xiang-Bo Wan %A Rou Jiang %A Fang-Yun Xie %A Zhen-Yu Qi %A Ai-Ju Li %A Wei-Jun Ye %A Yi-Jun Hua %A Yu-Liang Zhu %A Xiong Zou %A Ling Guo %A Hai-Qiang Mai %A Xiang Guo %A Ming-Huang Hong %A Ming-Yuan Chen %J PLOS ONE %D 2014 %I Public Library of Science (PLoS) %R 10.1371/journal.pone.0090048 %X 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¨C2009 were analyzed retrospectively. Among these patients, 171 patients had superficial residual NPC (¡Ü1 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¡À3.8 VS 62.6¡À4.3 Gray (Gy), P = 0.67) and regional lymph nodes (55.8¡À5.0 VS 57.5¡À5.7 Gy, P = 0.11) was comparable in both groups. For brachytherapy, IMBT subgroup had a lower boost radiation dosage than ICBT subgroup (11.0¡À2.9 VS 14.8¡À3.2 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. %U http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0090048