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E-ISSN: 3061-9947
Comparision of Radiation-induced Secondary Malignancy Risk Between Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy with Simultaneous Integrated Boost in the Treatment of Nasopharyngeal Carcinoma
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Original Article
VOLUME: 52 ISSUE: 3
P: 398-404
2019

Comparision of Radiation-induced Secondary Malignancy Risk Between Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy with Simultaneous Integrated Boost in the Treatment of Nasopharyngeal Carcinoma

Acta Haematol Oncol Turc 2019;52(3):398-404
DOI: 10.5505/aot.2019.49379
Emel Hacıislamoğlu 1
1. Karadeniz Technical University, Faculty of Medicine, Department of Radiation Oncology, Trabzon
2.
No information available.
No information available
Received Date: 2019-07-22T23:01:17
Accepted Date: 2019-12-27T14:23:46
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Abstract

INTRODUCTION

To compare intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) with simultaneous integrated boost (SIB) in terms of secondary cancer risk after radiotherapy (RT) of nasopharyngeal cancer using the concept of organ equivalent dose (OED).

METHODS

IMRT-SIB and VMAT-SIB plans were generated with identical objective functions for 5 patients with nasopharyngeal cancer of early stage. Three different planning target volumes (PTVs); PTV1, PTV2 ve PTV3 were delineation for each patient and the prescribed doses were 52.8 Gray (Gy), 59.4 Gy and 69.3 Gy delivered in 33 fractions, respectively. Differential dose-volume histograms (DVHs) were used to calculate the OEDs with Schneider’s “full mechanistic” and “specific mechanistic sarcoma” dose-response models. Calculations of OED and excess absolute risks (EAR) were applied to the brain stem, spinal cord, oral cavity, parotid, pharynx, mandibular glands, mandible and soft tissue.

RESULTS

Clinically acceptable plans were achieved for all the IMRT-SIB and VMAT-SIB plans. OED-based secondary cancer risk for parotids was significant higher when VMAT-SIB was used. No significant difference was found in terms of the OED and EAR for other organs, including the brain stem, spinal cord, oral cavity, pharynx, mandibular glands, mandible and soft tissue.

DISCUSSION AND CONCLUSION

The most OED-based secondary cancer risks were similar when IMRT-SIB and VMAT-SIB were applied. However, the second cancer risk for the parotids was slightly higher when VMAT-SIB was used.