Challenges and Differences in External Radiation Therapy for Retinoblastoma: From Standard Techniques to New Developments

• Published in: Tumori Vol. 103; no. 5; pp. 438 - 442
• Main Authors: Hiçsönmez, Ayşe, Güney, Yıldız, Dizman, Ayşen, Dirican, Bahar, Arslan, Yakup, Atakul, Tugba, Uysal, Hasan, Gündüz, Kaan, Taçyıldız, Nurdan, Ünal, Emel, Dinçaslan, Handan, Andrieu, Meltem Nalça
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-09-2017
• Subjects: Humans; Radiation Injuries; Radiosurgery; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated; Retinoblastoma - pathology; Retinoblastoma - radiotherapy; Retinoblastoma - surgery; Pediatric oncology; Radiotherapy; Retinoblastoma
• ISSN: 0300-8916; 2038-2529
• DOI: 10.5301/tj.5000406

Aims
The purpose of this study is to calculate the treatment plans and to compare the dose distributions and dose-volume histograms (DVH) for 6 external radiotherapy techniques for the treatment of retinoblastoma as well as intensity-modulated radiotherapy (IMRT) and fractionated stereotactic radiotherapy (Cyberknife).
Methods
Treatment plans were developed using 6 techniques, including an en face electron technique (ET), an anterior and lateral wedge photon technique (LFT), a 3D conformal (6 fields) technique (CRT), an inverse plan IMRT, tomotherapy, and conventional focal stereotactic external beam radiotherapy with Cyberknife (SBRT). Dose volume analyses were carried out for each technique.
Results
All techniques except electron provided similar target coverage. When comparing conformal plan with IMRT and SBRT, there was no significant difference in planning target volume dose distribution. The mean volume of ipsilateral bony orbit received more than 20 Gy, a suggested threshold for bone growth inhibition. The V20 Gy was 73% for the ET, 57% for the LFT, 87% for the CRT, 65% for the IMRT, 66% for the tomotherapy, and 2.7% for the SBRT.
Conclusions
This work supports the potential use of IMRT and SBRT to spare normal tissues in these patients.