Second cancer risk after 3D-CRT, IMRT and VMAT for breast cancer

• Published in: Radiotherapy and oncology 2014-03, Vol.110 (3), p.471-476
• Main Authors: Abo-Madyan, Yasser, Aziz, Muhammad Hammad, Aly, Moamen M.O.M, Schneider, Frank, Sperk, Elena, Clausen, Sven, Giordano, Frank A, Herskind, Carsten, Steil, Volker, Wenz, Frederik, Glatting, Gerhard
• Format: Article
• Language: English
• Subjects: Aged; Breast cancer; Breast Neoplasms - radiotherapy; Female; Hematology, Oncology and Palliative Medicine; Humans; Intensity modulated radiation therapy (IMRT); Middle Aged; Neoplasms, Radiation-Induced; Neoplasms, Second Primary - etiology; Organ equivalent dose (OED); Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy, Conformal - adverse effects; Radiotherapy, Intensity-Modulated - adverse effects; Risk; Second cancer risk
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2013.12.002

Abstract Purpose Second cancer risk after breast conserving therapy is becoming more important due to improved long term survival rates. In this study, we estimate the risks for developing a solid second cancer after radiotherapy of breast cancer using the concept of organ equivalent dose (OED). Materials and methods Computer-tomography scans of 10 representative breast cancer patients were selected for this study. Three-dimensional conformal radiotherapy (3D-CRT), tangential intensity modulated radiotherapy (t-IMRT), multibeam intensity modulated radiotherapy (m-IMRT), and volumetric modulated arc therapy (VMAT) were planned to deliver a total dose of 50 Gy in 2 Gy fractions. Differential dose volume histograms (dDVHs) were created and the OEDs calculated. Second cancer risks of ipsilateral, contralateral lung and contralateral breast cancer were estimated using linear, linear-exponential and plateau models for second cancer risk. Results Compared to 3D-CRT, cumulative excess absolute risks (EAR) for t-IMRT, m-IMRT and VMAT were increased by 2 ± 15%, 131 ± 85%, 123 ± 66% for the linear-exponential risk model, 9 ± 22%, 82 ± 96%, 71 ± 82% for the linear and 3 ± 14%, 123 ± 78%, 113 ± 61% for the plateau model, respectively. Conclusion Second cancer risk after 3D-CRT or t-IMRT is lower than for m-IMRT or VMAT by about 34% for the linear model and 50% for the linear-exponential and plateau models, respectively.