An elective radiation dose of 46 Gy is feasible in nasopharyngeal carcinoma treated by intensity-modulated radiotherapy A long-term follow-up result

作者：Hung Tsung Min; Fan Kang Hsing; Chen Eric Yen Chao; Lin Chien Yu; Kang Chung Jan; Huang Shiang Fu; Liao Chun Ta; Ng Shu Hang; Wang Hung Ming; Chang Joseph Tung Chieh^*

来源：Medicine, 2017, 96(6): e6036.

DOI：10.1097/MD.0000000000006036

• elective irradiation
• intensity-modulated radiotherapy
• nasopharyngeal carcinoma
• radiation dose
• treatment outcome

The purpose of this study is to compare the treatment outcome of different radiation doses of elective neck irradiation (ENI) in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT).
In total, 504 patients with nondisseminated NPC who underwent magnetic resonance imaging before radical IMRT between 2000 and 2008 were retrospectively reviewed. The patients were classified into 2 groups based on the ENI dose: low ENI when the ENI dose was 46 Gy (n=446) and high ENI when the ENI doses were 50 to 60 Gy (n=58). All the patients in both the groups received a median dose of 72 Gy to the gross tumor and involved nodes. The fraction size was 2 Gy per fraction. Matching was performed between low ENI and high ENI in a 2: 1 ratio, and the matching criteria were N-stage, T-stage, treatment modality, pathology classification, sex, and age.
The median follow-up for all patients was 63.5 months. In all patients, the 5-year progression-free survival (PFS), local control (LC), regional control (RC), distantmetastasis-free survival (DMFS), overall survival (OS), and cancer-specific survival (CSS) for low ENI and high ENI patients were 69.0% and 63.2%(P=0.331), 89.0% and 83.9% (P=0.235), 90.1% and 85.2% (P=0.246), 86.8% and 76.6% (P= 0.056), 77.5% and 80.8%(P=0.926), and 84.4% and 82.5%(P=0.237), respectively. In thematched-pair analysis, the 5-year PFS, LC, RC, DMFS, OS, and CSS formatched lowENI and high ENI patientswere 74.1% and 63.2%(P=0.134), 92.0% and 83.9%(P=0.152), 90.1% and 85.2% (P=0.356), 86.2% and 76.6% (P=0.125), 87.0% and 80.8% (P=0.102), and 88.6% and 82.5% (P=0.080), respectively. In the multivariable analysis for all patients, the ENI group was not a significant factor for PFS, LC, RC, DMFS, OS, and CSS.
A low ENI dose of 46 Gy in 23 fractions is feasible in NPC patients treated with IMRT, and this concept should be validated in the prospective studies.

• 出版日期2017-2
• 单位长春大学