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.
"Adjuvant radiation therapy after breast-conserving surgery is an essential treatment for early breast cancer . Previous studies, however, have reported increased risk of radiation related toxicity resulting in non-breast cancer related deaths, which are mainly caused by cardiovascular disease and lung cancer [2,3,4]. Recently published study has reported that the cardiac mortality ratio for left sided (vs. "
[Show abstract][Hide abstract] ABSTRACT: Purpose
To quantify the cardiac dose reduction during breathing adapted radiotherapy using Real-time Position Management (RPM) system in the treatment of left-sided breast cancer.
Materials and Methods
Twenty-two patients with left-sided breast cancer underwent CT scans during breathing maneuvers including free breathing (FB), deep inspiration breath-hold (DIBH), and end inspiration breath-hold (EIBH). The RPM system was used to monitor respiratory motion, and the in-house self respiration monitoring (SRM) system was used for visual feedback. For each scan, treatment plans were generated and dosimetric parameters from DIBH and EIBH plans were compared to those of FB plans.
All patients completed CT scans with different breathing maneuvers. When compared with FB plans, DIBH plans demonstrated significant reductions in irradiated heart volume and the heart V25, with the relative reduction of 71% and 70%, respectively (p < 0.001). EIBH plans also resulted in significantly smaller irradiated heart volume and lower heart V25 than FB plans, with the relative reduction of 39% and 37%, respectively (p = 0.002). Despite of significant expansion of lung volume using inspiration breath-hold, there were no significant differences in left lung V25 among the three plans.
In comparison with FB, both DIBH and EIBH plans demonstrated a significant reduction of radiation dose to the heart. In the training course, SRM system was useful and effective in terms of positional reproducibility and patient compliance.
"The development of RP depends on the treatment-related factors [22,23], such as radiation dose, fractionation schedule, volume and region of lung irradiated, use of concurrent chemotherapy, and patient-related factors [6,9], such as pre-existing lung disease, poor pulmonary function, being a smoker, and genetic predisposition. It has been previously reported that radiation-induced lung sequelae affect as many as 9% of patients with breast cancer being treated with RT . However, using computer-based radiation treatment planning systems dramatically decreased the incidence of these lung sequelae [25,26]. "
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study is to evaluate the correlation between the conventional plan parameters and dosimetric parameters obtained from conformal radiotherapy (RT) planning, and between these parameters and radiation pneumontitis (RP) incidence.
Clinical and dosimetric data of 122 patients that were treated with mastectomy and adjuvant 3D conformal RT (39% received 2-field RT [2-FRT], and in addition, 61% received 4-field RT [4-FRT]) were retrospectively analyzed. Central lung depth (CLD), maximum lung depth (MLD), and lung length were measured by the conventional plan. Lung dose-volume histograms (DVH) were created with conformal planning, and the lung volumes receiving 5 to 50 Gy (V(5Gy) to V(50Gy)) were calculated. Minimum (D(min)), maximum (D(max)), and mean doses (D(mean)) for the ipsilateral lung and bilateral lungs were measured by DVH. Correlations between 3D dosimetric data and 2D radiographic parameters were analyzed.
The conventional plan parameters did not significantly differ between 2-FRT and 4-FRT. The conformal plan D(min), D(max), and D(mean) values were higher in 4-FRT versus 2-FRT. CLD and MLD were correlated with DVH parameter V(5Gy) to V(45Gy) values for ipsilateral, as well as bilateral lungs for 2-FRT. MLD and ipsilateral D(mean) via 2-FRT planning had the strongest positive correlation (r=0.76, p<0.01). Moderate correlations existed between CLD and ipsilateral and bilateral lung V(5Gy-45Gy), and between MLD and bilateral lung V(5Gy-45Gy) values in 2-FRT. Only four patients developed symptomatic RP, 4 with 4-FRT and one with 2-FRT.
The conformal plan parameters were strongly correlated with dose-volume parameters for breast 2-FRT. With only 4 cases of Grade 3 RP observed, our study is limited in its ability to provide definitive guidance, however assuming that CLD is an indicator for RP, V(20Gy) could be used as a predictor for RP and for 2-FRT. A well-defined parameters are still required to predict RP in 4-FRT.
"L'un des principaux enseignements tiré des séries de la littérature concerne l'importance de la définition des volumes cibles et des organes à risque. En effet, la prise en compte de toutes les incertitudes, notamment celles dues aux mouvements respiratoires , et la détermination rigoureuse de l'amplitude des marges de sécurité conditionnent étroitement la précision du traitement, son efficacité et sa toxicité potentielle          . La diffusion des techniques de contrôle de la respiration constitue donc une priorité afin d'améliorer la qualité et les résultats de la radiothérapie. "
[Show abstract][Hide abstract] ABSTRACT: To compare respiratory-gated conformal radiotherapy versus conventional conformal radiotherapy for the irradiation of non-small cells lung cancer and breast cancer.
The STIC 2003 project was a comparative, non-randomized, multicenter and prospective study that included in 20 French centers between April 2004 and June 2008, 634 evaluable patients, 401 non-small cells lung cancer and 233 breast cancers.
The final results confirmed the feasibility and good reproducibility of the various respiratory-gated conformal radiotherapy systems regardless of tumour location. The results of this study demonstrated a marked reduction of dosimetric parameters predictive of pulmonary, cardiac and esophageal toxicity, especially for non-small cells lung cancer, as a result of the various respiratory gating techniques. These dosimetric benefits were mainly observed with deep inspiration breath-hold techniques (ABC and SDX), which markedly increased the total lung volume compared to the inspiration-synchronized system based on tidal volume (RPM). For non-small cells lung cancer, these theoretical dosimetric benefits were correlated with a significant reduction in clinically acute and late toxicities, especially the pulmonary. For breast cancer, although less clear due to the lower total dose, there was a decrease in the dose delivered to the heart, potentially reducing the risk of cardiac toxicity in the long-term, especially during the irradiation of the left breast, and a reduction in dose to the contra lateral breast.
Respiratory-gated radiotherapy appears to be essential to reduce the risk of acute and late toxicities, especially for lungs and heart, during irradiation of non-small cells lung cancer and breast cancers.
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