Int. J. Environ. Res. Public Health 2012, 9(11), 4223-4240; doi:10.3390/ijerph9114223
Article

Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy

1 National Institute of Ionizing Radiation Metrology, ENEA Casaccia Research Center, Rome, Italy/Via Anguillarese 201, Rome 00123, Italy 2 Radiation Oncology Department, Sant'Andrea Hospital, University of Rome La Sapienza/Via di Grottarossa, 1035-1039, Rome 00189, Italy 3 Medical Physics Department, Sant'Andrea Hospital, University of Rome La Sapienza/Via di Grottarossa, 1035-1039, Rome 00189, Italy
* Author to whom correspondence should be addressed.
Received: 28 August 2012; in revised form: 15 October 2012 / Accepted: 19 October 2012 / Published: 19 November 2012
(This article belongs to the Special Issue Radiation and Cancer Risk)
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Abstract: The aim of the present paper is to compare the integral dose received by non-tumor tissue (NTID) in stereotactic body radiation therapy (SBRT) with modified LINAC with that received by three-dimensional conformal radiotherapy (3D-CRT), estimating possible correlations between NTID and radiation-induced secondary malignancy risk. Eight patients with intrathoracic lesions were treated with SBRT, 23 Gy × 1 fraction. All patients were then replanned for 3D-CRT, maintaining the same target coverage and applying a dose scheme of 2 Gy × 32 fractions. The dose equivalence between the different treatment modalities was achieved assuming α/β = 10Gy for tumor tissue and imposing the same biological effective dose (BED) on the target (BED = 76Gy10). Total NTIDs for both techniques was calculated considering α/β = 3Gy for healthy tissue. Excess absolute cancer risk (EAR) was calculated for various organs using a mechanistic model that includes fractionation effects. A paired two-tailed Student t-test was performed to determine statistically significant differences between the data (p ≤ 0.05). Our study indicates that despite the fact that for all patients integral dose is higher for SBRT treatments than 3D-CRT (p = 0.002), secondary cancer risk associated to SBRT patients is significantly smaller than that calculated for 3D-CRT (p = 0.001). This suggests that integral dose is not a good estimator for quantifying cancer induction. Indeed, for the model and parameters used, hypofractionated radiotherapy has the potential for secondary cancer reduction. The development of reliable secondary cancer risk models seems to be a key issue in fractionated radiotherapy. Further assessments of integral doses received with 3D-CRT and other special techniques are also strongly encouraged.
Keywords: stereotactic body radiation therapy; integral dose; linear-quadratic model; biologically effective dose; BED; radio-induced secondary malignancies

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MDPI and ACS Style

D'Arienzo, M.; Masciullo, S.G.; Sanctis, V.D.; Osti, M.F.; Chiacchiararelli, L.; Enrici, R.M. Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy. Int. J. Environ. Res. Public Health 2012, 9, 4223-4240.

AMA Style

D'Arienzo M, Masciullo SG, Sanctis VD, Osti MF, Chiacchiararelli L, Enrici RM. Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy. International Journal of Environmental Research and Public Health. 2012; 9(11):4223-4240.

Chicago/Turabian Style

D'Arienzo, Marco; Masciullo, Stefano G.; Sanctis, Vitaliana D.; Osti, Mattia F.; Chiacchiararelli, Laura; Enrici, Riccardo M. 2012. "Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy." Int. J. Environ. Res. Public Health 9, no. 11: 4223-4240.

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