Comparison of breast sequential and simultaneous integrated boost using the biologically effective dose volume
Moamen M O M Aly1,2, Yasser Abo-Madyan3,4, Lennart Jahnke5
1Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany. m.aly@au.edu.eg.
Radiation Oncology (London, England)
|February 3, 2016
Summary
This study introduces a method to radiobiologically compare sequential (SEQ) and simultaneously integrated boost (SIB) breast radiotherapy. SIB demonstrated superior dosimetric advantages for both the breast target volume and organs at risk compared to SEQ.
Area of Science:
- Radiation Oncology
- Medical Physics
- Cancer Therapy
Background:
- Comparing different radiotherapy fractionation schemes requires robust radiobiological modeling.
- Sequential (SEQ) and Simultaneously Integrated Boost (SIB) are two common breast radiotherapy techniques with distinct dose delivery patterns.
- Accurate comparison necessitates accounting for varying fraction sizes and their biological impact.
Purpose of the Study:
- To develop and present a method for radiobiologically comparing SEQ and SIB breast radiotherapy techniques.
- To evaluate the dosimetric and radiobiological differences between SEQ and SIB using biologically effective dose (BED).
- To assess the impact on breast target volumes and organs at risk (OARs).
Main Methods:
- A novel method based on identically prescribed biologically effective dose (iso-BED) was employed.
- Three-dimensional dose distributions were converted to BED distributions, considering different fractionation schemes and alpha/beta ratios.
- Cumulative BED volume histograms (BEDVH) were generated for comparative analysis of SEQ and SIB plans in ten breast cancer patients.
- Organs at risk, including lungs, heart, and contralateral breast, were evaluated.
Main Results:
- SIB demonstrated a reduction in biological mean dose to the breast by approximately 3%.
- Significant dose reductions were observed for organs at risk: ipsilateral lung and heart by about 10%, and contralateral breast and lung by about 7%.
- The iso-BED approach facilitated a direct radiobiological comparison between the two techniques.
Conclusions:
- Biologically effective dose (BED) based comparisons are essential when evaluating radiotherapy plans with differing fraction sizes.
- Simultaneously Integrated Boost (SIB) radiotherapy offers dosimetric advantages over sequential (SEQ) techniques for breast targets and organs at risk when delivering equal prescribed BEDs.
- The presented method provides a framework for optimizing breast radiotherapy planning and delivery.
