Cancer risk after breast proton therapy considering physiological and radiobiological uncertainties
| Autor: | Iuliana Toma-Dasu, Alexandru Dasu, Anna M. Flejmer, Apostolos Raptis, Oscar Ardenfors, Jakob Ödén |
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| Jazyk: | angličtina |
| Předmět: |
Organs at Risk
Proton Biophysics General Physics and Astronomy Lower risk 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Breast cancer Neoplasms Relative biological effectiveness Proton Therapy Medicine Humans Radiology Nuclear Medicine and imaging Proton therapy business.industry Radiotherapy Planning Computer-Assisted Absolute risk reduction Cancer General Medicine medicine.disease 3. Good health 030220 oncology & carcinogenesis Breathing Protons business Nuclear medicine Relative Biological Effectiveness |
| Zdroj: | Physica Medica |
| ISSN: | 1120-1797 |
| DOI: | 10.1016/j.ejmp.2020.06.012 |
| Popis: | Background The reduced normal tissue dose burden from protons can reduce the risk of second cancer for breast cancer patients. Breathing motion and the impact of variable relative biological effectiveness (RBE) are however concerns for proton dose distributions. This study aimed to quantify the impact of these factors on risk predictions from proton and photon therapy. Materials and methods Twelve patients were planned in free breathing with protons and photons to deliver 50 Gy (RBE) in 25 fractions (assuming RBE = 1.1 for protons) to the left breast. Second cancer risk was evaluated with several models for the lungs, contralateral breast, heart and esophagus as organs at risk (OARs). Plans were recalculated on CT-datasets acquired in extreme phases to account for breathing motion. Proton plans were also recalculated assuming variable RBE for a range of radiobiological parameters. Results The OARs received substantially lower doses from protons compared to photons. The highest risks were for the lungs (average second cancer risks of 0.31% and 0.12% from photon and proton plans, respectively). The reduced risk with protons was maintained, even when breathing and/or RBE variation were taken into account. Furthermore, while the total risks from the photon plans were seen to increase with the integral dose, no such correlation was observed for the proton plans. Conclusions Protons have an advantage over the photons with respect to the induction of cancer. Uncertainties in physiological movements and radiobiological parameters affected the absolute risk estimates, but not the general trend of lower risk associated with proton therapy. |
| Databáze: | OpenAIRE |
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