鼻咽癌使用強度調控放射治療影響耳下腺功能的因子

Factors Influencing Parotid Gland Function in Nasopharyngeal Carcinoma Treated Mainly with Intensity-Modulated Radiotherapy

劉文山(Wen-Shan Liu) ； 蘇茂昌(Mao-Chang) ； 辛宗翰(Chung-Han Hsin) ； 李永康(Jong-Kang Lee) ； 周希諴(His-Hsien Chou) ； 郭祥吉(Hsiang-Chi Kuo)

《放射治療與腫瘤學》 11卷1期 (2004/03) Pp. 1-7

https://doi.org/10.6316/TRO/200411(1)1

摘要

目的：報告鼻咽癌使用強度調控放射治療（IMRT）的經驗以及利用唾液腺閃爍攝影檢查來評估影響照射後耳下腺功能的因子。 材料與方法：本研究包括了公元2000年8月至2001年5月，共19名主要以強度調控放射療法治療的鼻咽癌病患。其中12名期別是屬於第一至第二期，另外7名則是屬於第三至第四期的患者（1997 AJCC）。在治療計畫設定劑量方面，可視腫瘤體積的外加計畫體積（GTV-PTV）、可視腫大轉移淋巴腺、與臨床標靶體積的外加計畫體積（CTV-PTV）各為70、65-70、與55-60 Gy；其分次劑量則各為2.12、2.0-2.12、及1.7-1.8 Gy。有6位病患在強度調控放射治療之前接受了9.0至18.0 Gy的三度空間順形放射治療。除了體外放射治療有18位病患接受了鼻咽腔內近接治療，劑量為7.0 Gy分兩次治療。所有第二至四期的患者當中除一位外均接受了兩次藥物cisplatin與5-FU的同步化學治療，放療後則接受了兩到四次化學治療。平均追蹤期為13個月（8 至18個月）。患者在放射治療之前及治療之後一、三、與六個月以唾液腺閃爍攝影檢查來評估耳下腺功能的影響，評估影響治療後唾液分泌比率因子的方法為Mann-Whitney rank-sum test。 結果：平均GTV-PTV與CTV-PTV的劑量各為70.9及63.2 Gy；平均右側與左側耳下腺劑量各為38.1及38.6 Gy。在八到十八個月追蹤期間所有19位病患原發部位與頸部淋巴結腫瘤均完全消失。治療當中發生急性頰黏膜發炎反應屬 RTOG第三等者有15位（79%），臨床分類第一級至第三級口乾症各有9、9及1位。治療前後的唾液分泌比率達到統計學上有意義差別（p = 0.002），不利保留耳下腺功能的因子有N（+）期別（p = 0.03）、耳下腺中值劑量大於35 Gy（p = 0.038）、耳下腺百分之五十體積劑量大於35 Gy（p = 0.032）以及吃檳榔時間超過五年者（p = 0.029）。 結論：本研究顯示對於鼻咽癌而言同步強度調控放射與化學治療是一安全且有效的治療方法。頸部淋巴腺轉移、耳下腺中值劑量、耳下腺百分之五十體積劑量以及吃檳榔習慣等因子會影響治療後的耳下腺功能。

關鍵字

鼻咽癌 ； 口乾症 ； 強度調控放射治療 ； 唾液腺閃爍攝影

並列摘要

Purpose : To report the experience with intensity-modulated radiotherapy (IMRT) in the treatment of nasopharyngeal carcinoma and to determine the factors influencing post-irradiation parotid gland function measured by sialoscintigraphy. Methods and Materials : This study included 19 patients with NPC treated mainly with IMRT between August 2000 and May 2001. Twelve of these patients had Stage I-II disease and seven had Stage III-IV disease (1997 AJCC). The planning target volume of gross target volume (GTV-PTV), visible lymph node and planning target volume of clinical target volume (CTV-PTV) were designed to receive 70, 65-70 and 55-60 Gy with daily fraction of 2.12, 2.0-2.12 and 1.7-1.8 Gy, respectively. Six patients received 9-18 Gy 3D conformal radiotherapy prior to IMRT. Except from external beam, there were eighteen patients received intracavitary brachytherapy with the dose of 7.0 Gy in two fractions. All Stage II to IV cases except one received two courses of concurrent chemo-radiotherapy with cisplatin and 5-FU during radiotherapy and two to four cycles thereafter. The mean follow-up time was 13.0 months (range: 8-18 months). Objective parotid gland function was assessed by sialoscintigraphy pre-irradiation and at one, three and six months post-irradiation. Mann-Whitney rank-sum test was used to determine the factors associated with the changes in post-irradiated secretion ratio (SR). Results :The mean dose administered to the GTV-PTV and CTV-PTV were 70.9 and 63.2 Gy, respectively. The mean dose administered to the right and left parotid glands was 38.1 and 38.6 Gy, respectively. All of the 19 patients had complete response of primary and lymph node disease at follow-up ranging from 8 to 18 months after radiotherapy (mean, 13 months). Acute side-effects which developed during this concurrent chemo-radiotherapy were RTOG Grade III mucositis in 15 (79%) patients. Clinical xerostomia of Grade I was noted in 9 patients, Grade II in 9, and Grade III in one. There was a significant difference between the pre- and post-irradiation parotid gland SR (p= 0.002). Poor prognostic factors for the preservation of parotid gland function were N (+) Stage (p= 0.03), median dose of parotid gland greater than 35 Gy (p = 0.038), 50% volume of parotid gland greater than 35 Gy (p = 0.032) and the habit of betel quid chewing for longer than 5 years (p = 0.029). Conclusions :This study demonstrated that the combination of IMRT and chemotherapy is an effective and safe method for the treatment of nasopharyngeal cancer. The N stage, median dose of parotid gland, 50% volume dose to the parotid glands and the habit of betel quid chewing were correlated with post-irradiated parotid gland function.

並列關鍵字

nasopharyngeal carcinoma ； xerostomia ； intensity modulated radiotherapy ； sialoscintigraphy