Long-Term Outcome of Postoperative Adjuvant Radiotherapy for Thymoma

胸腺瘤手術後輔助放射治療之長期結果分析

呂慧君(Huei-Chun Lu) ； 詹建勝(Jian-Sheng Jan) ； 林進清(Jin-Ching Lin)

《放射治療與腫瘤學》 15卷2期 (2008/06) Pp. 101-108

https://doi.org/10.6316/TRO/200815(2)101

摘要

目的：分析胸腺瘤術後輔助放射線治療的長期結果。
材料與方法：本研究選擇經病理證實是胸腺瘤的病人，且接受切除手術及40 Gy以上的術後放射線治療。自1984年10月至2002年8月期間，本院癌症登記資料庫中有38位符合條件。我們回顧了這些病人的病歷、放射線治療紀錄及檢查影像。腫瘤的分期是依據Masaoka分期系統。這些病人的中位數年齡是47歲（自22歲到83歲）；男性／女性：26位／12位；第一期有4位，第二期有15位，第三期有15位，第四期有4位。放射治療技術主要是前後相對照野、楔形濾板(wedge pair)或三度空間順形治療，劑量中位數是50 Gy（40至68 Gy），以傳統分次方式給予。我們使用Kaplan-Meier統計方式來分析總存活率、局部無病存活率及無轉移存活率。
結果：經過中位數11年的追蹤，38位病人中有13位病人腫瘤復發（2位是局部復發，7位是遠處轉移，4位是局部復發合併遠處轉移）。五年的總存活率、局部無病存活率及無轉移存活率分別是75.5%、82.1%和83.5%；十年的總存活率、局部無病存活率及無轉移存活率分別是51.2%、82.1%和56.7%。單變項分析中，腫瘤分期和手術切除範圍大小是最重要的預後因素。年齡、性別、放射線劑量及是否合併有重症肌無力等因素並不影響存活率。在晚期腫瘤（第三期和第四期）的十年總存活率(24.1% vs. 89.5%, P=0.0010)、十年局部無病存活率(59.9% vs. 100%, P=0.0031)及十年無轉移存活率(29.6% vs. 82.9%, P=0.0084)均較早期腫瘤（第一期和第二期）為差。有完全切除腫瘤的病人的十年總存活率(60.6% vs. 11.3%, P=0.0083)、十年局部無病存活率(86.4% vs. 53.3%, P=0.1101)及十年無轉移存活率(66.4% vs. 0%, P=0.0002)較只有部份腫瘤切除的病人為佳。多變項分析中，只有腫瘤分期是影響預後的因素。
結論：腫瘤分期和手術切除範圍大小是最重要的預後因素。術後輔助放射線治療對於早期腫瘤的控制有很好的效果，但對晚期腫瘤的治療效果不佳。在未來的研究中，應該考慮對晚期腫瘤的病人輔助化學治療。

關鍵字

胸腺瘤 ； 放射線治療 ； Masaoka分期系統

並列摘要

Purpose: To analyze the long-term outcome of postoperative radiotherapy for thymoma.
Materials and Methods: Patients with pathological-proven thymoma and receiving surgical resection plus postoperative radiotherapy 40 Gy were eligible for this retrospective study. From October 1984 to August 2002, 38 eligible patients were obtained from our Cancer Registration Database. We reviewed hospital charts, radiotherapy records and diagnostic imaging studies thoroughly. Tumor staging was defined according to the Masaoka staging system. Baseline characteristics of patients were median age 47 (range 22-83), male/female=26/12, stage Ⅰ/Ⅱ/Ⅲ/Ⅳ=4/15/15/4. The radiotherapy was delivered by a wedge-pair or 3-D conformal-beam technique with a median dose of 50 Gy (range 40-68 Gy) by conventional fractionation. The end points were overall survival (OS), locoregional disease-free survival (LDFS) and metastasis-free survival (MFS) by the Kaplan-Meier method.
Results: After a median follow-up of 11 years, 13 of 38 patients had tumor relapse (2 locoregional recurrence, 7 distant metastasis, and 4 locoregional plus distant failure). The 5-year and 10-year of OS, LDFS, and MFS for all patients were 75.5% and 51.2%, 82.1% and 82.1%, and 83.5% and 56.7%, respectively. On univariate analysis, stages and the extent of surgical resection were the most important prognostic factors. Age, gender, radiation dose, and association of myasthenia gravis did not affect the survival significantly. The 10-year OS (24.1% vs. 89.5%, P=0.0010), LDFS (59.9% vs. 100%, P=0.0031), and MFS (29.6% vs. 82.9%, P=0.0084) were significantly lower in patients with advanced-stage (Ⅲ+Ⅳ) than in those with early-stage (Ⅰ+Ⅱ). Patients with total resection had better 10-year OS (60.6% vs. 11.3%, P=0.0083), LDFS (86.4% vs. 53.3%, P=0.1101), and MFS (66.4% vs. 0%, P=0.0002) than those with subtotal resection. The multivariate analysis revealed that stage was the only significant prognostic factor.
Conclusion: Stages and the extent of surgical resection are the most important prognostic factors. Postoperative adjuvant radiotherapy has good tumor control for earlystage disease but is inadequate for advanced-stage disease. Chemotherapy should be considered for advanced-stage patients in future trials.

並列關鍵字

Thymoma ； Radiation therapy ； Masaoka staging systeml