Brain Stem Doses for Patients of T3/T4 Nasopharyngeal Carcinoma Treated by Bid Irradiation and Concomitant Chemotherapy

局部嚴重性鼻咽癌病人一天兩次放射治療合併化學治療之腦幹劑量分佈長期追蹤研究成果

蔡玉真(Stella Y. C. Tsai) ； 鄭鴻鈞(Skye Hongiun Cheng) ； 簡哲民(James Jer-Min Jian) ； 黃昭明(Chao-Ming Huang) ； 閻愷正(K. Lawrence Yen) ； 詹光裕(Kwan-Yee Chan) ； 呂思韻(Szu-Yun Leu) ； 林燕君(Yen-Chun Lin) ； 褚乃銘(Nei-Min Chu) ； 譚傳德(Tran-Der Tan)

《放射治療與腫瘤學》 12卷3期 (2005/09) Pp. 167-180

https://doi.org/10.6316/TRO/200512(3)167

摘要

目的：根據我們過去的經驗發現，對於局部嚴重性第三期及第四期的鼻咽癌病人，於顱底骨方向之放射線治療範圍安全距離必須大於一公分才能達到良好之局部控制。為了達到此目的，部份腦幹也會接受與原發腫瘤相近之高劑量；為了減少高放射治療劑量對腦幹之傷害，本院設計使用一天二次放射治療配合化學治療，以期達到提高局部控制率，而不造成長期腦幹受傷之研究。
材料與方法：於1991年9月至1998年12月，總共有69位T3、T4鼻咽癌病人於和信醫院接受一天二次放射治療合併化學治療。原發腫瘤接受一天二次放射治療，一次1.2 Gy，每週治療五天，總共74.4 Gy分62次給予。對於每一個病人之放射治療範圍之設計，於一開始之大範圍治療至40.8至43.2 Gy；安全距離為15 mm，第一次縮小之治療範圍治療劑量至60 Gy，安全距離則降為7 mm至10 mm。而最後加強照射之14.4 Gy，則安全距離降為3至7 mm。69位病人有25位病人於1996年之後接受治療，其原始治療計畫可以用目前我們三度空間的治療計畫來分析其腦幹的劑量分佈曲線。這25位病人中其中5位病人於三年內因疾病死亡，所以不列入統計。
結果：經過至少49個月以及追蹤時間中位值97個月的追蹤，這20位病人的五年局部控制率為93.8%，我們只觀察到其中一位病人有輕微的第二級同側上肢麻痺。這些病人沒有人因腦幹受傷而導致死亡。平均腦幹接受最高劑量為75.12 Gy。平均腦幹接受大於50 Gy、55 Gy、60 Gy、65 Gy及70 Gy的體積分別為10.32 ml、7.72 ml、5.67 ml、3.58 ml及l.72 ml。
結論：由我們的經驗，一天二次分次放射治療可以給予局部嚴重性鼻咽癌之病人足夠之放射線劑量以達良好局部控制而不造成長期腦幹功能之損傷。

關鍵字

鼻咽癌 ； 腦幹放射治療耐受度 ； 一天兩次放射治療

並列摘要

Purpose: Our prior study revealed that at least 1 cm safe margin at clivus direction is necessary to obtain good local control of nasopharyngeal carcinoma (NPC). We retrospectively studied whether hyperfractionation irradiation to treat T3/T4 NPC patients could decrease the long-term side effect to the brain stem.
Patients and Methods: Sixty-nine patients with T3/T4 (American Joint Committee on Cancer, 1997 staging system) NPC were treated with concomitant chemotherapy and twice a day radiation followed by adjuvant chemotherapy between September 1991 and December 1998 in Koo Foundation Sun Yat-Sen Cancer Center, Taipei. The planning dose of radiation was 74.4 Gy in 62 fractions, twice a day, 5 days per week. Every patient had 15 mm safe margin at clivus direction in the initial field to 40.8-43.2 Gy, 7mm to 10 mm to 60Gy at the 2nd boost field, and 3-7 mm at the final boost field to a total dose of 74.4 Gy. Twenty-five patients were treated between 1996 and 1998; their previous treatment plan data could be retrieved for analysis in our current CMS (Computerized Medical Systems, INC) three dimension treatment planning system for dose volume histogram calculation of brain stem. Five patients died from disease within 3 years after completion of treatment were excluded from the analysis.
Results: With a minimal and median follow-up of 49 and 97 months, respectively, 5-year local control rate of the 20 patients was 93.8%. Brain stem toxicity was observed in one of 20 patients with the manifestation of grade Ⅱ sensory loss at ipsilateral upper limb. There was no treatment related death. The average maximal dose to brain stem was 75.12 Gy and mean dose was 35.56 Gy. The average volumes of brain stem dose more than 50 Gy, 55 Gy, 60 Gy, 65 Gy, and 70 Gy were 10.32 ml, 7.72 ml, 5.67 ml, 3.58 ml, and 1.72 ml, respectively.
Conclusion: Our data indicated that adequate irradiation dose could be given safely with hyperfractionation for T3/T4 NPC patients to achieve good local tumor control without significant long-term side effect to brain stem.

並列關鍵字

Nasopharyngeal carcinoma ； Brain stem tolerance ； Hyperfractionation radiation