Mycosis Fungoides: A Case Report

蕈樣黴菌病：病例報告

謝忠志(Chung-Ching Hsieh) ； 吳孟浩(Meng-Hao Wu) ； 賴允亮(Yuen-Liang Lai) ； 陳弘政(Hung-Cheng Chen) ； 奚正義(Cheng-I Hsi) ； 張國華(Kou-Hwa Chang) ； 鐘昌宏(Chang-Hung Chung) ； 戴宏旗(Hung-Chi Dai)

《放射治療與腫瘤學》 6卷2期 (1999/06) Pp. 131-140

https://doi.org/10.6316/TRO/199906(2)131

摘要

蕈樣黴菌病是一罕見的T-細胞淋巴癌，然而約佔所有表皮T-細胞淋巴癌病例的半數。長久以來放射線被用於治療這個甚具輻射敏感性之疾病，不過相當比例的病人有廣泛的皮膚病變，或是病灶在先前照射過的範圍以外甚或之中復發，因此數十年來放射治療工作者，一直探尋能夠使皮膚（“圓柱”狀的人體之表層）接受較大範圍與較高劑量照射且又能接受其毒性的技術。使用現代直線加速器所產生的低能量電子，在有限深度內釋出能量，得以避免較深部的組織受到輻射，加以三十多年前史丹佛大學發展一種“六對照野接”，能在符合上述要求下達到較佳的劑量分佈，自此接受全身皮膚電子束放射治療的病人，有較好的臨床反應與較小的毒性。
我們採用這種“六對照野法”治療一位有廣泛皮膚病變的49歲男性病患“射源至表面的距離拉長為323公分，並架設一塊壓克力板以發散射束及衰減電子能量。從直線加速器所產生6 MeV初能量的電子將變為2.62 MeV。加速器的輸出減為0.0648 cGy/Mu （在最高劑量深度處），準直儀全開至40乘以40平方公分，且不加錐孔。每一成對照野的射束各與水準軸成上或下20度之夾角，倍率係數(multiplication factor) 經測量為2.68，腫瘤劑量定於皮膚表面下5毫米處（位於90%等劑量曲線），總計每單一照野的照射必須1212 MU。射束平坦度在垂直及水準方向分別為±5%與±10%之內，使用熱發光劑量計(TLD)的測量值來評估體表45個部位的劑量均勻度，是否追加照射或遮罩則依個別情況而定。每週治療4個連續日，每2日為一週期，每l天治療半數的成對照野，單次劑量是2 Gy，共照射18個週期，達到36 Gy的總劑量，但在療程的正中段休息10天。皮膚病灶對此療法反應良好，搔癢在前半療程結束前已完全緩解，副作用（手掌和腳掌的皮膚炎和頭髮完全脫落）亦可接受，然而該病人拒絕後續的輔助治療。
儘管全身皮膚電子束放射治療可以達到良好的初期臨床效果，至今對於蕈樣黴菌病病人的處理依然是個挑戰。此疾病有極高的復發傾向，目前要完全治癒病變已超越局部範圍的病人，機會依然渺茫。除了放射治療，尚有許多療法已在臨床應用或研究中，我們建議對這類病人採取複合式治療以提昇長期療效。

關鍵字

蕈樣黴菌病 ； 表皮T-細胞淋巴癌 ； 全身皮膚電子束放射治療 ； 六對照野法

並列摘要

Mycosis fungoides is a rare T-cell lymphoma, but it accounts for about half of all cases of cutaneous 7-cell lymphoma. Radiation has long been used to treat patients with this radiosensitive disease. However, a significant proportion of patients present with generalized plaques or recurrence of lesions outside or even within the previously irradiated area, it challenged radiotherapists for decades how to irradiate skin (the superficial layer of a somewhat ”cylinder-like” human body) with not only larger field and higher dose but also tolerable toxicity. Radiation with low energy electrons generated by modern linear accelerators, depositing their energy within limited depth could spare deeper tissues. The six-dual-field technique, which provide more satisfying dose distribution for these requirements was developed at Stanford University three decades ago. Since then, the patients treated with total skin electron beam radiation would have better clinical response and minor toxicity.
We adopted the six-dual-field technique to treat a 49-year-old male with generalized plaques. The source-to-surface distance was extended to be 323 cm, and an acrylic beam spoiler was installed to scatter the beam and attenuate the electron energy. The resulting electron energy was 2.62 MeV, generated by a 6 MeV Linac, the output of which was degraded to deliver 0.0648 cGy/MU (at the depth of maximum dose, d(subscript max). The collimator was fully opened to 40×40 cm^2 without a cone. The hinge angle of the dual-field was determined to be 20 degrees. The measured multiplication factor was 2.68. We prescribed a tumor dose at 5 mm depth beneath the skin surface (90% isodose profile). Overall, 1212 MU were required for each field. Beam flatness was within ±5% and ±10% in the vertical and horizontal dimensions, respectively. Thermoluminescent dosimeters (TLD) were used to evaluate dose homogeneity at 45 sites. Individualized boost or shielding was used at appropriate sites. Radiation therapy was administered for 4 consecutive days per week, with 2 days constituting a treatment cycle. On the first day of a cycle, half of the 6 dual-fields were irradiated, with the other half treated the other day A total dose of 36 Gy over 18 cycles was given with a fraction dose of 2 Gy. A 10-day midway break was given. The skin lesions responded well to this regimen, and itching was completely relieved prior to completion of the first half of the treatment course. Side effects (marked dermatitis of palms and soles and total hair loss) were acceptable. The patient refused subsequent adjuvant therapy.
Despite total skin radiation can achieve good initial clinical outcome, the management of patients with mycosis fungoides is still challenging. This disease has a predisposition to relapse, and the chance is dismal to cure patients with the disease beyond limited plaque stage for the time being. In additicn to radiation therapy, a variety of modalities have been in clinical use or in investigation. We suppose combination treatment should be administered in these patients to improve long-term control.

並列關鍵字

Mycosis fungoides ； Cutaneous T-cell lymphoma ； Total skin electron beam radiation therapy ； Six-dual-field technique