Cardiac and lung complication probabilities after breast cancer irradiation.
ABSTRACT To assess for locoregional irradiation of breast cancer patients, the dependence of cardiac (cardiac mortality) and lung (radiation pneumonitis) complications on treatment technique and individual patient anatomy.
Three-dimensional treatment planning was performed for 30 patients with left-sided breast cancer and various breast sizes. Two locoregional techniques (Techniques A and B) and a tangential field technique, including only the breast in the target volume, were planned and evaluated for each patient. In both locoregional techniques tangential photon fields were used to irradiate the breast. The internal mammary (IM)-medial supraclavicular (MS) lymph nodes were treated with an anterior mixed electron/photon field (Technique A) or with an obliquely incident mixed electron/photon IM field and an anterior electron/photon MS field (Technique B). The optimal IM and MS electron field dimensions and energies were chosen on the basis of the IM-MS lymph node target volume as delineated on CT-slices. The position of the tangential fields was adapted to match the IM-MS fields. Dose-volume histograms (DVHs) and normal tissue complication probabilities (NTCPs) for the heart and lung were compared for the three techniques. In the beam's eye view of the medial tangential fields the maximum distance of the heart contour to the posterior field border was measured; this value was scored as the Maximum Heart Distance.
The lymph node target volume receiving more than 85% of the prescribed dose was on average 99% for both locoregional irradiation techniques. The breast PTV receiving more than 95% of the prescribed dose was generally smaller using Technique A (mean: 90%, range: 69-99%) than using Technique B (mean: 98%, range: 82-100%) or for the tangential field technique (mean: 98%, range: 91-100%). NTCP values for excess cardiac mortality due to acute myocardial ischemia varied considerably between patients, with minimum and maximum values of 0.1 and 7.5% (Technique A), 0.1 and 5.8% (Technique B) and 0.0 and 6.1% (tangential tech.). The NTCP values were on average significantly higher (P<0.001) by 1.7% (Technique A) and 1.0% (Technique B) when locoregional breast irradiation was given, compared with irradiation of the left breast only. The NTCP values for the tangential field technique could be estimated using the Maximum Heart Distance. NTCP values for radiation pneumonitis were very low for all techniques; between 0.0 and 1.0%.
Technique B results in a good coverage of the breast and locoregional lymph nodes, while Technique A sometimes results in an underdosage of part of the target volume. Both techniques result in a higher probability of heart complications compared with tangential irradiation of the breast only. Irradiation toxicity for the lung is low in all techniques. The Maximum Heart Distance is a simple and useful parameter to estimate the NTCP values for cardiac mortality for tangential breast irradiation.
- [show abstract] [hide abstract]
ABSTRACT: In radiation therapy of breast cancer several photon fields are used. Proper matching of the fields and minimizing the irradiated lung volume can be obtained by suitable beam blocking and appropriate angulation of the gantry, collimator and turntable. To facilitate the simulation procedure a new general method has been developed to calculate these angles, the position of the beam blocks and the field dimensions exactly.Radiotherapy and Oncology 02/1986; 5(1):47-57. · 4.52 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: The long-term results of a randomized clinical trial evaluating the effect of postoperative radiotherapy as an adjuvant to radical mastectomy are presented. There were 1115 patients including 27 protocol deviants. The follow-up time is 11-20 years. In the first part a conventional roentgen unit was used, and in the second part a 60Co unit, with considerably increased dosage and altered treatment plan. Both types of radiation techniques lowered the incidence of loco-regional recurrences significantly, but had no significant influence on the overall survival. The relapse-free survival was significantly improved by 60Co radiation in Stage II patients, but was unaffected by radiation in the other subgroups. Regarding survival, Stage II patients with medially located tumors seemed to benefit more from 60Co radiation than those with lateral tumors. A significant increase in the number of deaths caused by myocardial infarction was observed in Stage I patients having 60Co radiation, indicating that the radiation dose to the heart is of significance.International Journal of Radiation OncologyBiologyPhysics 06/1986; 12(5):727-32. · 4.52 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: To assess cardiac mortality, coronary artery disease, myocardial dysfunction, and valvular heart disease in women younger than 65 years of age, at least 10 years after adjuvant radiotherapy following mastectomy in early breast cancer. Ninety women (45-64 years old) with Stage II breast cancer without relapse, included in the South Sweden Breast Cancer Trial (premenopausal arm), with or without adjuvant postoperative radiotherapy +/- cyclophosphamide were examined with myocardial scintigraphy and echocardiography/Doppler, 10-17 years after radiotherapy. Thirty-four patients had been irradiated for left-sided tumors, 33 for right-sided tumors, and 23 patients had not been treated with radiotherapy. The radiotherapy (conventional roentgen, electron beams, and high-energy photon beams combined, in each patient) included the chest wall and the regional lymph nodes, with a specified target dose of 38-48 Gy, administered in daily fractions of 1.9-2.4 Gy, 5 days/week. No cardiac deaths were found among the original 275 patients randomized to adjuvant therapy. In the 90 patients examined, abnormal findings were recorded for ECG (14 patients), exercise test (5 patients), myocardial scintigraphy (6 patients), thickening of valve cusps (14 patients), and mild valvular regurgitation (20 patients). All patients had normal systolic function. Diastolic dysfunction was observed in 6 patients (abnormal relaxation in 4 patients and restrictive filling abnormality in 2 patients). Although no significant differences were found between the 3 study groups, there was a tendency to more abnormal findings after radiotherapy. Women younger than 50 years of age at the time of adjuvant radiotherapy following mastectomy in early breast cancer, had no serious cardiac sequelae 13 years (median) later, despite partly old-fashioned radiation techniques.International Journal of Radiation OncologyBiologyPhysics 04/1999; 43(4):745-54. · 4.52 Impact Factor