Análise comparativa das doses cardíacas recebidas por pacientes com câncer de mama esquerda planejadas com duas formas alternativas de delineamento do CTV da cadeia mamária interna / Comparative analysis of heart doses received by patients with left breast cancer planned with two alternative internal mamary delineation CTVs

Propósito. Com a publicação, na última década, do resultado de grandes estudos demonstrando a correlação entre a dose de radiação recebida no coração e o aumento de eventos cardíacos adverso. Nosso estudo investiga a possibilidade de reduzir a dose cardíaca de radiação sem utilizar os protocolos ideais de inspiração profunda (DIBH). Metodologia. Analisamos os parâmetros dosimétricos referentes a 43 pacientes recebidas no departamento de radioterapia da Santa Casa de Maceió tratadas com radioterapia adjuvante em mama ou plastrão esquerdos incluindo fossa e cadeia mamária interna (MI). Todas as pacientes foram submetidas a duas tomografias e planejamentos distintos, com e sem inspiração profunda (DIBH), em um protocolo simplificado adequado para a realidade do Sistema Único de Saúde (SUS). Foram analisados os efeitos dosimétricos sobre o volume alvo, o coração, o pulmão esquerdo com o DIBH simplificado e com formas alternativas de delineamento da cadeia mamária interna. Resultados. Em nosso estudo, o protocolo de DIBH simplificado demonstrou uma redução da dose média cardíaca mesmo em pacientes incluindo radiação nodal regional ampla (692 cGy vs 502 cGy - p < 0,0001). As doses médias no ventrículo esquerdo (VE) (1222 cGy vs 857 cGy ­ p < 0,0001), na artéria coronária anterior descendente (LAD) (3739 cGy vs 3345 cGy ­ p = 0,0001) e outros parâmetros como o V25% do coração (12,4% vs 7,7% - p < 0,0001) também se mostraram reduzidas. Os delineamentos alternativos da cadeia mamária interna (MI) não produziram alterações significantes nas doses cardíacas ou pulmonares. O melhor parâmetro para predizer o benefício do DIBH foi a expansibilidade do pulmão esquerdo (r = 0,6 - p < 0,0001), sendo que os pacientes com relação entre o pulmão normal e o inspirado menor que 1,3-1,4 não obtiveram benefício significativo. Doses pulmonares também tiveram melhora estatisticamente significativa com o DIBH (média 1448 cGy vs 1294 cGy ­ p < 0,0001; V20 32,6% vs 28,2% - p <0,0001; V5 48,7% vs 45,4% - p < 0,0005), Conclusão. Nosso estudo indica que um protocolo simplificado de DIBH pode ser uma alternativa para beneficiar pacientes selecionados que necessitam reduzir a dose cárdica de radiação em tratamentos e mama esquerda e drenagens regionais em serviços de radioterapia de alta demanda e recursos limitados

Purpose. In the last decade, seminars studies demonstrated the correlation between radiation doses received in the heart with the incidence of cardiac disease, such as acute coronary events. This aroused the interest in new techniques to reduce this problem. Numerous studies have already shown that Deep Inspiration Breath Hold (DIBH) may be the best option for reducing cardiac dose. However, the vast majority of these investigations were carried out in a different scenario from the one found in our reality. Our study investigated the feasibility of reducing the cardiac dose without using an ideal DIBH protocol, which are difficult to implement in services with high demand and low economic support. Methods. The dosimetric parameters of 43 patients from the radiotherapy department of Santa Casa de Maceió were analyzed. All patients were treated with adjuvant radiotherapy to the left breast, including supraclavicular fossa and internal mammary chain (IM). The patients underwent two different CT scans and planning, with and without DIBH, in a simplified protocol suitable for the reality of tour public health system (Free Breath Hold; no respiratory training; selection of only the patients with greater benefit). The dosimetric impact on the heart, its substructures and the left lung were studied with the simplified DIBH and with alternative forms of delineation to the IM. Results. The simplified DIBH protocol demonstrated, in our study, a reduction in mean cardiac dose for patients including wide regional nodal radiation (692 cGy vs 502 cGy - p < 0.0001). The doses for the Left ventricular (1222 cGy vs 857 cGy ­ p < 0.0001), the Left anterior-descending coronary (3739 cGy vs 3345 cGy ­ p = 0.0001) and other parameters such as heart V25% (12.4% vs 7, 7% - p < 0.0001) were also reduced. The doses to the heart did not achieve statistically significant reduction with alternative delineation of the MI CTV. The best parameter predicting the benefit of DIBH was the left lung expansion (r = 0.6 - p < 0.0001), with patients with a ratio lower than 1.3-1,4 having no significant benefit. Pulmonary doses also showed a statistically significant improvement with DIBH (Dmed 1448 cGy vs 1294 cGy ­ p < 0.0001; V20 32.6% vs 28.2% - p <0.0001; V5 48.7% vs 45, 4% - p < 0.0005), but the reductions were small, as was the increase in pulmonary dose when the MI CTV is outlined to joining the supraclavicular fossa. Conclusion. Our study indicates that a simplified DIBH protocol may serve as an option to benefit selected patients with locally advanced breast cancer treated in departments with high occupation of the Linacs and low capacity for investment in new technology

Cardiac dosimetry of deep inspiration breath-hold technique in whole breast irradiation for left breast cancer after breast-conserving surgery / 中华放射肿瘤学杂志

Objective To study the effect of deep inspiration breath-hold(DIBH)technique on the heart dose in whole breast irradiation(WBI)for left breast cancer after breast-conserving surgery, and to investigate the anatomical factors for heart dose. Methods Fifteen patients with left breast cancer who received WBI after breast-conserving surgery and met breathing control requirements were prospectively enrolled as subjects. Simulated CT scans were performed during free breathing(FB)and DIBH. The WBI plans were optimized based on DIBH images.The position,volume,and radiation doses to the heart and lung were compared between the status of FB and DIBH. Correlation of heart dose with various anatomical factors was analyzed in FB status. Between-group comparison of categorical data was made by nonparametric Wilcoxon rank test.A two-variable correlation analysis was made by the Pearson method.Results There was no significant difference in heart volume between the status of FB and DIBH(P=0.773).The volume of both lungs was significantly larger in DIBH status than in FB status(P=0.001). The mean and maximum doses and V5-V40for the heart,left anterior descending coronary artery,left ventricle,right ventricle,and left lung were significantly lower in DIBH status than in FB status(all P<0.05). The greater DIBH increased the lung volume,the greater the mean heart dose decreased. In FB status,the left breast volume,heart-to-lung volume ratio,distance between the inferior margins of breast and heart,and maximum heart margin distance showed a linear correlation with heart dose. Particularly, the heart-to-lung volume ratio and maximum heart margin distance were independently correlated with heart dose. Conclusions DIBH technique in WBI for left breast cancer after breast-conserving surgery significantly reduces heart and lung doses compared with FB. Changes in lung volume are the basis for improving the relative anatomical location of the heart. The heart-to-lung volume ratio and maximum heart margin distance may provide a reference for DIBH technique.

Evaluation of the effect of deep inspiration breath-hold on radiation therapy for left breast cancer and the correlation between cardiac chest wall contact distance and cardiac exposure / 中国综合临床

Objective To compare the exposure to heart and other organs of the application of DIBH (deep inspiration breath-hold)and FB(free breath)in the left breast cancer radiotherapy,and the relationship between CCD(cardiac contact distance)and heart dose was analyzed.Methods Thirty patients with left breast cancer were examined with CT scans using DIBH and FB respectively,and then the dose was calculated by TPS(treatment planning system).The dose of heart,left anterior descending branch and left ventricle were analyzed by DVH(dose volume histogram).FB-CCDax(Axial cardiac chest wall contact distance)and FB-CCDps(sagittal heart chest wall contact distance)in CT images were measured based on FB.Results The parameters showed that,in radiotherapy with the application of DBIH technology,the irradiated volume of heart, left anterior descending branch(LAD),left ventricle(LV)of were significantly lower than that in the organs in the FB,the mean dose(Dmean)of heart of the former was 0.8 Gy,compared with 2.7 Gy in the latter one(P<0.005).The Dmean of LAD was 4.0Gy,compared with 12.7Gy in the latter one(P<0.001); The Dmean of LV was 1.2Gy,compared with 3.6Gy in the latter one(P<0.005).In the DIBH and FB radiotherapy,the Dmean of the heart,left anterior descending branch and left ventricle was correlated with FB-CCDps,but not with FB-CCDax.Conclusion DIBH is a simple treatment technique that can effectively reduce the cardiac radiation dose without loss of target dose.FB-CCDps is a potential predictor of cardiac exposure,and the longer the FB-CCDps distance is,the higher the cardiac dose is.The study found that at least 70% of patients with left breast cancer would benefit from DIBH and reduce the radiation exposure to normal cardiac structures,so DIBH should be used as a routine clinical application.

Cardiac dose reduction with breathing adapted radiotherapy using self respiration monitoring system for left-sided breast cancer

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. RESULTS: 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. CONCLUSION: 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.