Radiotherapy-induced secondary cancer risk for breast cancer: 3D conformal therapy versus IMRT versus VMAT

• Published in: Journal of radiological protection 2014-06, Vol.34 (2), p.325-331
• Main Authors: Lee, Boram, Lee, Sunyoung, Sung, Jiwon, Yoon, Myonggeun
• Format: Article
• Language: English
• Subjects: BEIR VII; Biological and medical sciences; Biological effects of radiation; breast cancer; Breast Neoplasms - mortality; Breast Neoplasms - radiotherapy; Causality; Computer Simulation; Female; Fundamental and applied biological sciences. Psychology; Gynecology. Andrology. Obstetrics; Humans; Incidence; lifetime attributable risk; Mammary gland diseases; Medical sciences; Models, Biological; Models, Statistical; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); Neoplasms, Radiation-Induced - mortality; Neoplasms, Second Primary - etiology; Organs at Risk - radiation effects; Proportional Hazards Models; Radioprotection; Radiotherapy, Intensity-Modulated - methods; Radiotherapy, Intensity-Modulated - mortality; Reproducibility of Results; Risk Factors; secondary cancer risk; Sensitivity and Specificity; Survival Rate; Tissues, organs and organisms biophysics; Tumors
• ISSN: 0952-4746; 1361-6498
• DOI: 10.1088/0952-4746/34/2/325

This study evaluated the secondary cancer risk to various organs due to radiation treatment for breast cancer. Organ doses to an anthropomorphic phantom were measured using a photoluminescent dosimeter (PLD) for breast cancer treatment with 3D conformal radiation therapy (3D-CRT), intensity modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT). Cancer risk based on the measured dose was calculated using the BEIR (Biological Effects of Ionizing Radiation) VII models. The secondary dose per treatment dose (50.4 Gy) to various organs ranged from 0.02 to 0.36 Gy for 3D-CRT, but from 0.07 to 8.48 Gy for IMRT and VMAT, indicating that the latter methods are associated with higher secondary radiation doses than 3D-CRT. The result of the homogeneity index in the breast target shows that the dose homogeneity of 3D-CRT was worse than those of IMRT and VMAT. The organ specific lifetime attributable risks (LARs) to the thyroid, contralateral breast and ipsilateral lung per 100 000 population were 0.02, 19.71, and 0.76 respectively for 3D-CRT, much lower than the 0.11, 463.56, and 10.59 respectively for IMRT and the 0.12, 290.32, and 12.28 respectively for VMAT. The overall estimation of LAR indicated that the radiation-induced cancer risk due to breast radiation therapy was lower with 3D-CRT than with IMRT or VMAT.