Intensity-modulated radiation therapy for nasopharyngeal carcinoma: a review

Abstract

Introduction Advances in radiation therapy, such as intensity-modulated radiation therapy (IMRT), have allowed high-dose delivery to tumors while sparing normal tissues. However, IMRT requires careful delineation of target volumes to prevent marginal recurrences. Results and discussion This review discusses the recent advances in the treatment of nasopharyngeal carcinoma with particular emphasis on IMRT. Multiple phase III trials that have relied on conventional radiotherapy have shown a survival benefit to concurrent chemoradiotherapy (CCRT) over radiotherapy (RT) alone. Two randomized trials using IMRT have demonstrated decreased xerostomia rates compared to conventional radiotherapy while still maintaining excellent local control rates, although follow-up was short. While modern locoregional results are excellent, 90 % or more, distant-metastasis-free rates are not as impressive, ranging from 66 to 93 % among studies. Conclusion IMRT is an advanced technique, its excellent treatment outcomes have been reproduced in many single institution studies. Perhaps IMRT-delivered RT can replace the benefit provided by chemotherapy when added to conventional RT. Future studies should focus on reducing target volumes to minimize toxicity while dose-escalating for high-risk patients.

Long-term survival of nasopharyngeal carcinoma patients with Stage II in intensity-modulated radiation therapy era

“…IMRT for the treatment of NPC has been reported in numerous studies to be more effective (12). Whether the benefit gained with chemotherapy in Stage II NPC could be reduced by IMRT is unknown.…”

“…Data from the most recent publications have shown that intensity-modulated radiation therapy (IMRT) can greatly increase the treatment outcomes and improve the quality of life of NPC patients when compared with 2D-RT (12). With the superb outcome of NPC treated with IMRT, it is reasonable to question the additive benefit of chemotherapy used with IMRT in Stage II.…”

The New T Staging System for Nasopharyngeal Carcinoma Based on Intensity Modulated Radiation Therapy: Results of a Prospective Multicentric Clinical Study

“…The improved outcomes may be attributed to the following factors: (1) compared to 2D-RT, IMRT, with a capacity to provide highly conformal and precise coverage with sharp dose gradients, has been accepted as the standard treatment technique for NPC [14], with regional control rates for stages T1-T3 and stage T4 of 94%-99%, and 83%, respectively [15]; (2) coverage of parapharyngeal space and skull base provided by IMRT can avoid the problem of low radiation doses to these regions, which commonly exists in conventional field arrangement of regular 2D-RT, and improve the regional control rate for T2 and T3 stages [16]; (3) the application of conformal radiation therapy and chemoradiotherapy dramatically increases the regional control rate for locoregional advanced NPC and thus makes differences between T substages statistically insignificant [17][18][19]. However, the seventh edition of the UICC/AJCC staging standard, published in 2009, is based on results from conventional 2D-RT techniques and fails to reflect the influence on staging of innovations in diagnosis and therapy.…”

Nasopharyngeal Carcinoma

“…Alternative volume delineation strategies and dose fractionation schemes are thoroughly discussed in a review article by Wang et. al (Wang et al 2012 ). Selected fractionation schemes are briefl y reviewed in Table 3 .…”