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Dosimetric Comparison of Three-Dimensional Conformal Radiotherapy, Forward-Planned Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy in Intact Breast Radiotherapy without Lymphatic Irradiation
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Original Article
VOLUME: 52 ISSUE: 2
P: 293-302
2019

Dosimetric Comparison of Three-Dimensional Conformal Radiotherapy, Forward-Planned Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy in Intact Breast Radiotherapy without Lymphatic Irradiation

Acta Haematol Oncol Turc 2019;52(2):293-302
DOI: 10.5505/aot.2019.06977
Zumrut Arda Kaymak Cerkesli 1
Fevziye İlknur Kayalı 2
Rahşan Habiboğlu 2
1. Süleyman Demirel University, Radiation Oncology Department
2. Ankara Numune Training And Education Hospital Radiation Oncology Clinic
3.
No information available.
No information available
Received Date: 2019-05-21T14:56:37
Accepted Date: 2019-08-30T10:05:39
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Abstract

INTRODUCTION

The present study aimed to determine the most suitable technique for whole breast radiotherapy after breast conserving surgery in patients without lymph node involvement; those that constitute the majority of breast cancer cases. Three-dimensional conformal radiotherapy (3DCRT), that is widely used, forward planned intensity-modulated radiotherapy (forIMRT), that is accepted to be cost-effective, and volumetric modulated arc therapy (VMAT), that has become available recently, were dosimetrically compared.

METHODS

Computed tomography simulation cross-sections of 16 patients with right breast cancer and 19 patients with left breast cancer, who had been treated with forIMRT, were used in the study. All planning was done using Eclipse 10.0 treatment planning system. A conventional scheme consisting of a total dose of 50Gy given in 25 fractions was used. The techniques were compared in terms of target volume and critical organ (ipsilateral lung, heart, contralateral breast and contralateral lung) doses.

RESULTS

We successfully achieved target coverage (TC) by all three techniques. Forward IMRT led to a higher decrease in planned target volume (PTV) maximum dose (Dmax), in comparison to 3DCRT. The best PTV dose homogeneity was achieved with VMAT. forIMRT resulted in higher reductions in all critical organ doses when compared to 3DCRT, and the decrease was significantly higher in the ipsilateral lung mean dose (Dmean) and Dmax and the volume of ipsilateral lung receiving ≥40Gy (V40), and contralateral breast Dmax and V5. Compared to the other two methods, VMAT led to a greater decrease in Dmax, V20, V30 and V40 of the ipsilateral lung and Dmax and V35 of the heart in left breast cancer patients; but led to a significant increase in Dmean, V5 and V10 of the ipsilateral lung; Dmean, Dmax, and V5 of the contralateral lung and breast, and Dmax, Dmean, V5 and V10 of the heart in right breast cancer patients; and Dmean, V5, and V10 of the heart in left breast cancer patients.

DISCUSSION AND CONCLUSION

forIMRT provides a better dosimetry than 3DCRT for intact breast radiotherapy; therefore, it should be preferred, whenever possible. More homogeneous dose distributions are achieved with VMAT. Additionally, while ipsilateral critical organ high doses decrease by VMAT, ipsilateral and contralateral critical organ low doses show a significant increase. The outcomes of this condition should be studied in clinical studies with long-term follow-up.