Ayşen DİZMAN, Yıldız GÜNEY, Ela Delikgöz SOYKUT, Özlem DERİNALPOR, Dinçer YEĞEN

LAKRİMAL GLAND TÜMÖRLERİNDE CYBERKNİFE ® İLE FRAKSİYONE STEREOTAKTİK RADYOTERAPİ UYGULAMASI

AMAÇ: Radyasyon duyarlılığı yüksek olan orbital yapılara yakın yerleşimli lakrimal gland tümörlerinde CyberKnife® ile uygulanan hipofraksiyone stereotaktik radyoterapinin etkinlik ve güvenilirliğini değerlendirmek.GEREÇ ve YÖNTEM: Mayıs 2009 ve Haziran 2011 tarihleri arasında kliniğimize başvuran, lakrimal gland tümörü tanısı olan 6 hastaya CyberKnife® (Accuray Incorporated, Sunnyvale, CA) ile fraksiyone stereotaktik radyoterapi uygulandı. Hastaların 3'ü kadın, 3'ü erkekti. Ortanca yaş 33 (aralık, 16-51 yaş) olarak saptandı. Beş hastada patolojik alt tip adenoid kistik karsinom, kalan birinde ise pleomorfik adenomdu. Tedavi planlama işlemi öncesi hastaların tümüne ince kesit planlama BT'si ve MRG çekildi. Görüntüler CyberKnife® tedavi planlama çalışma istasyonuna aktarılarak, hedef volüm ve kritik organ konturlama işlemi yapıldı. Tedavi 3-8 fraksiyonda (ortanca, 5 fraksiyon), total doz ortanca 30 Gy (aralık 23.5- 40 Gy) olacak şekilde uygulandı. Reçete edilen doz ortanca % 83'lük izodoz eğrisine tanımlandı.BULGULAR: Ortanca takip süresi 9.5 ay (aralık, 4-26 ay) olarak belirlendi. Takiplerde 2 hastada tam, 2 hastada kısmi yanıt tespit edilirken, daha önce eksentrasyon uygulanan iki hastada kitle stabildi. Hastaların tümüne takiplerinde görme muayenesi yapıldı. Tedavi öncesi görme fonksiyonu tam olan 4 hastanın son kontrollerinde de görme fonksiyonunda azalma ya da kayıp saptanmadı. SONUÇ: CyberKnife® ile uygulanan fraksiyone stereotaktik radyoterapi, tüm orbital tümörler gibi lakrimal gland tümörleri için de, tümöre maksimum doz verirken, radyasyon duyarlılığı yüksek optik yapılara tolerans doz sınırlarında doz vermeye olanak sağlayan etkili bir tedavi seçeneğidir. Tümörde küçülme ya da progresyonun önlenmesi ve bu sırada görme fonksiyonun korunması, kısa süreli tedavi gibi avantajlar bu yöntemin üstünlükleridir. Ancak vaka sayısının daha fazla olduğu ve uzun takipli çalışmalara ihtiyaç olduğunu düşünmekteyiz

Anahtar Kelimeler:

Stereotaktik radyoterapi, hipofraksiyonasyon, lakrimal gland tümörleri

Implementation of CyberKnife® Fractionated Stereotactic Rariotherapy for Lacrimal Gland Tumors

OBJECTIVE: The goal of this study is to evaluate the safety and efficacy of CyberKnife image-guided radiosurgery for lesions immediately adjacent to the orbital structures. MATERIAL and METHODS: We applied fractionated stereotactic radiotherapy with CyberKnife (Accuray Incorporated, Sunnyvale, CA) to six patients with lacrimal gland tumor who were admitted the period of May 2009-June 2011 to our clinic. There were three women, three men. The median age 33 year (range,16-51 year). Pathological subtypes were adenoid cystic carcinoma in five patients, while the remaining one was pleomorphic adenoma. Before treatment planing, thin-slice CT and MRI images were obtained. These images were transferred to the CyberKnife treatment-planning workstation and target volumes and critical structures were delineated manually. Treatment was delivered in 3-8 fractions up to mean total dose of 30 Gy (range, 23.5-40 Gy). The prescription dose was defined at a mean isodose of 83% (range, 72–92%). RESULTS: The mean follow-up period was 9.5 months (range, 4-26 months). It was determined that two patients had complete response, three patient had partial response in follow up period. The tumors remained stable in the other two patients. All patients had visual evaluation done during follow up period It wasn't determined decreasing or loss of vision function in four patients who had full vision function. CONCLUSION: Fractionated stereotactic radiotherapy with CyberKnife is an effective treatment alternative for tumors that located in orbital region as lacrimal gland tumors, which maximize the dose to the target while limiting the dose within tolerable doses for the radiosensitive orbital structures. Protecting visual function while decreasing of tumor size or preventing of tumor progression, and short treatment duration are advantages of this technique. Furthermore, longer follow-up studies and more number of cases are needed.

Keywords:

Stereotactic radiotherapy, hypofractionation, lacrimal gland tumors,

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