An Effective, Efficient and Safe Method to Deliver A Modified 3-D Radiotherapy in Locally Advanced Nasopharyngeal Carcinoma

局部嚴重侵犯鼻咽癌的一種有效率及安全的三度空間放射治療計劃

鍾邑林(Yih-Lin Chung) ； 鄭鴻鈞(Skye Hon-Giun Cheng) ； 蔡玉真(Stella Y.C. Tsai) ； 成佳憲(Jason C. Cheng) ； 康淑娌(Shu-Li Kang) ； 簡哲民(James Jer-Min Jian)

《放射治療與腫瘤學》 7卷3期 (2000/09) Pp. 137-145

https://doi.org/10.6316/TRO/200007(3)137

摘要

目的：設計一種改良式的三度空間放射治療計劃，不僅容易執行，減少腦幹照射，且仍可給予局部嚴重侵犯的鼻咽癌足夠劑量。
材料與方法：本研究選擇腫瘤侵犯靠近腦幹而無遠處轉移的T4鼻咽癌病人為此種治療計劃的標的。此計畫的設計乃藉由CMS-Focus之軟體系統，並經由西門子公司之加速器來執行。治療計劃的可行性是以執行的容易度，要求劑量分佈之達成度，腫瘤及正常組織之DVH和IMRT及3DCRT之比較，潛在輻射生物的效果和同步化學治療之毒性來評估。其治療結果之確定乃比較治療前後之核磁共振和核醫檢查之影像。
結果：此治療計劃每次只需執行2至4照野即可，最終達到腫瘤致死劑量而正常組織所接受的劑量仍在正常範圍內，腫瘤之DVH相似於IMRT之結果，而正常組織之DVH則相似於3DCRT之結果，在腫瘤密度愈大之區，其所受劑量之愈高，而正常組織內並無熱點(hot spot)，即使合併同步化學治療，病人仍可耐受而無重大毒性。藉由治療完成後的第三個月的核磁共振及核子醫學的掃描影像，證實腫瘤完全消失。
結論：此改良式的三度空間放射治療是一有效率及安全的方法，可以有效的治療局部嚴重侵犯的鼻咽癌，但仍需長期追蹤觀察，以確立臨床上之真正益處。

關鍵字

鼻咽癌,多分次放射線治療

並列摘要

Purpose: To generate a modified 3-D radiotherapy planning that can be delivered easily and safely, and treat the targets adequately in locally advanced nasopharyngeal carcinoma.
Materials and Methods: The stage 14 NPC patients without distant metastasis, especially with a huge tumor approaching or close to the brain stem, were selected for this Treatment planning under curative intent. The CMS.FOCUS planning system was used to generate these 3-D radiotherapy plans. The plans were evaluated with respect to daily treatment time and ease of treatment delivery, achievement of dose requirement to tumor with normal tissue sparing, dose-volume histograms of gross target volume and critical normal structures, potential radiobiological effects and toxicity of concurrent chemotherapy. The treatment responses were defined by the serial follow-up MRI and Tc-99mnuclear scans.
Results: Each time only 2-4 portals were needed to deliver a tumoricidal dose (200 cGyonce a day to 7000 cGy, or 120 cGy twice a day to 7440 cGy) to 100% of the primary tumor target volume while still keeping the doses of the adjacent critical normal structures within safety limits. The DVH of GTV is similar to that of IMRT but the DVHs of spinal cord and mandible are similar to those of 3DCRT. The highest dose was centered to the heavy tumor burden area. There was no any hot spot in normal tissue. This treatment was well tolerated and showed only moderate toxicity, even with concurrent chemotherapy. The complete response was confirmed by serial MRI and Tc.99m nuclear scans after treatment.
Conclusion: This modified 3-D radiotherapy was effective, efficient, and safe in treating locally advanced nasopharyngeal carcinoma. Longer follow-up and more patients are needed to establish the true clinical advantage.

並列關鍵字

Nasopharyngeal carcinoma,DVH,Hyperfractionation radiotherapy