Radiation-induced heart morbidity after adjuvant radiotherapy of early breast cancer - Is it still an issue?
- SourceAvailable from: Maria Patrizia D'Errico[Show abstract] [Hide abstract]
ABSTRACT: Today there is general awareness of the potential damage to the heart in left-sided (more than in right-sided) breast cancer radiotherapy (RT). Historical changes in tumor and heart doses are presented here along with the impact of different RT techniques and volumes. Individual and pharmacological risk factors are also examined with respect to radiation damage. The biological mechanisms of harm are only partially understood, such as the radiobiology of heart damage due to the presence of various radiosensitive structures and their topographic heterogeneity. Furthermore, individual variability may expose patients to higher or lower risks of late cardiac damage or death. Damage mechanisms and radiobiological characteristics in heart irradiation are presented in relation to dosimetric and biological parameters.Radiotherapy and Oncology 03/2012; 103(2):133-42. DOI:10.1016/j.radonc.2012.02.008 · 4.86 Impact Factor
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ABSTRACT: AIMS: Hypofractionation of postoperative radiotherapy for breast cancer has been evaluated in a number of large randomised clinical trials, but concerns remain over the late cardiac toxicity. In this study, we examined the predictions of the linear quadratic model on the estimated fraction size-corrected dose to the heart for four evidence-based hypofractionation regimens. MATERIALS AND METHODS: Dose plans for 60 left-sided breast cancer patients were analysed. All patients were planned with tangential fields for whole breast irradiation. Dose distributions were corrected to the equivalent dose in 2 Gy fractions (EQD(2)) using the linear quadratic model for five different fractionation schedules (50 Gy/25 fractions and four hypofractionation regimens) and for a range of α/β values (0-5 Gy). The mean EQD(2) to the heart ( [Formula: see text] ) and the volume receiving 40 Gy ( [Formula: see text] ), both as calculated from the EQD(2) dose distributions, were compared between schedules. RESULTS: For α/β = 3 Gy, [Formula: see text] favours hypofractionation for 40 Gy/15 fractions, 39 Gy/13 fractions and 42.5 Gy/16 fractions, but not for 41.6 Gy/13 fractions. All of the hypofractionation schedules result in lower [Formula: see text] compared with normofractionation. These results hold as long as α/β ≳ 1.5 Gy. If the heart is blocked from the treatment beam, the fraction size-corrected dose is lower for the first three hypofractionation schedules, compared with normofractionation, even for α/β = ∼1 Gy. CONCLUSION: For standard tangential field whole breast irradiation, most of the examined hypofractionation schedules are estimated to spare the heart when compared with normofractionation. The dose to the heart, adjusted for fraction size using the linear quadratic model, will generally be lower after hypofractionated compared with normofractionated schedules, even for very low values of α/β.Clinical Oncology 08/2012; 25(3). DOI:10.1016/j.clon.2012.07.012 · 2.83 Impact Factor
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ABSTRACT: BACKGROUND AND PURPOSE: This study aims at evaluating the effect of deep-inspiration breath hold (DIBH) on target coverage and dose to organs at risk in a large series of breast cancer patients. MATERIALS AND METHODS: Clinical dose plans for 319 breast cancer patients were evaluated: 144 left-sided patients treated with DIBH and 175 free-breathing (FB) patients (83 left-sided and 92 right-sided). All patients received whole breast irradiation with tangential fields, based on a forward-planned intensity-modulated radiation therapy (IMRT) technique. Dose to heart, ipsi-lateral lung and ipsi-lateral breast were assessed and median values compared between patient groups. RESULTS: Comparing group median values, DIBH plans show large reductions of dose to the heart compared with left-sided FB plans; V(20Gy) (relative volume receiving ⩾20Gy) for the heart is reduced from 7.8% to 2.3% (-70%, p<0.0001), V(40Gy) from 3.4% to 0.3% (-91%, p<0.0001) and mean dose from 5.2 to 2.7Gy (-48%, p<0.0001). Lung dose also shows a small reduction in V(20Gy) (p<0.04), while median target coverage is slightly improved (p=0.0002). CONCLUSIONS: In a large series of clinical patients we find that implementation of DIBH in daily clinical practice results in reduced irradiation of heart and lung, without compromising target coverage.Radiotherapy and Oncology 11/2012; 106(1). DOI:10.1016/j.radonc.2012.10.016 · 4.86 Impact Factor