Intensity-modulated radiotherapy for early-stage nasopharyngeal carcinoma - A prospective study on disease control and preservation of salivary function
Intensity-modulated radiotherapy for early-stage nasopharyngeal carcinoma - A prospective study on disease control and preservation of salivary function
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作者：
Kwong, DLW;Pow, EHN;Au, GKH
背景口干症是鼻咽癌放疗后常见的并发症。剂量学研究表明，调强放射治疗（IMRT）可以使部分腮腺免受高剂量辐射。前瞻性研究早期鼻咽癌调强放疗后的疾病控制和唾液功能。2000 ~ 2002年对33例T1、N 0 ~ N1、M0鼻咽癌患者进行调强放疗。处方剂量为肿瘤总体积68-70格雷（戈伊）分34次，计划靶区64-68戈伊，颈部肿大淋巴结70戈伊。19例患者在基线和IMRT完成后2个月、6个月、12个月、18个月和24个月进行了刺激全唾液（SWS）流量评估和刺激腮腺（SPS）流量评估。在中位随访2年时，仅观察到I型股骨颈失效。2年和3年局部控制率、无远处转移率和总生存率均为100%。2年淋巴结控制率和无进展生存率分别为100%和92.3%。腮腺的平均剂量为38.8戈伊。SWS和SPS流量显示持续恢复：60%和47.1%的患者在IMRT完成后1年分别恢复至少25%的基线SPS流量和SWS流量，2年时比例分别上升至85.7%和71.4%。唾液的pH值和缓冲能力也随着时间的推移而改善。保留腮腺的调强放射治疗取得了良好的局部控制，并有持续的恢复唾液流量，pH值和缓冲能力，在前2年调强放射治疗后的鼻咽癌患者。(C)2004年美国癌症协会。
BACKGROUND. Xerostomia is a uniform complication after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Dosimetric studies suggested that intensity-modulated RT (IMRT) can spare part of the parotid glands from high-dose radiation. Disease control and salivary function after IMRT for early-stage NPC was studied prospectively.METHODS. Thirty-three patients with T1,N0-N1,M0 NPC were treated with IMRT from 2000 to 2002. The prescribed dose was 68-70 grays (Gy) in 34 fractions to gross tumor volume, 64-68 Gy to the planning target volume, and 70 Gy to enlarged cervical lymph nodes. Nineteen patients had stimulated whole salivary (SWS) flow assessment and stimulated parotid salivary (SPS) flow assessment at baseline and at 2 months, 6 months, 12 months, 18 months, and 24 months after the completion of IMRT.RESULTS. At a median follow-up of 2 years, only I neck failure was observed. The 2-year and 3-year local control, distant metastases-free, and overall survival rates all were 100%. The lymph node control and progression-free survival rates were 100% at 2 years and 92.3% at 3 years, respectively. The average mean dose to the parotid gland was 38.8 Gy. The SWS and SPS flow showed continuous recovery: 60% and 47.1% of patients recovered at least 25% of their baseline SPS flow and SWS flow, respectively, at I year after completion of IMRT, and the proportions rose to 85.7% and 71.4%, respectively, by 2 years. The pH and buffering capacity of saliva also improved with time.CONCLUSIONS. Parotid-sparing IMRT achieved good locoregional control, and there was continuous recovery of salivary flow, pH, and buffering capacity in the first 2 years after IMRT in patients with NPC. (C) 2004 American Cancer Society.