Left-sided Breast Irradiation Research Articles

EP-1203: DIBH for left-sided breast radiotherapy: Does this equate to a reduction in OAR doses?

EP-1203: DIBH for left-sided breast radiotherapy: Does this equate to a reduction in OAR doses?

Abstract P5-14-15: Discovery and validation of simple heart measurements to screen patients who will benefit from deep inspiration breath hold for left breast irradiation

Abstract Purpose: Deep inspiration breath hold (DIBH) using active breath control in left-sided breast irradiation (RT) can significantly reduce radiation dose to heart and coronary arteries in selected patients. At our institution, a cutoff of V50% >10cc is currently used to identify patients who require DIBH. This dose-volume cutoff requires generation of a radiation plan in order to select patients. The purpose of this study was to identify simple 2-D measurements of the heart at the time of CT simulation that can help screen patients for DIBH in order to streamline the process for left-sided breast RT. Methods: This study evaluated CT simulation scans from 50 left-sided breast cancer patients treated with tangent RT alone, where 50% of patients were treated with DIBH. On each CT dataset, a tangential line was drawn between the medial and lateral tattoos. The following heart measurements were recorded by a blinded observer at 2, 3, 4, and 5 cm below the tattoos: (1) maximal heart distance (MHD) perpendicular to this line and (2) heart length (HL) along this line. Predictive models were created using two strategies; (1) step wise approach utilizing the most significant factor and (2) principle component analysis. Using C-statistics, 3 cutoffs with the highest correlations with heart dose were determined from the model. These cutoffs were validated in a cohort of 100 consecutive patients treated from Jan-May 2012. Results: Data from 49 patients in the derivation cohort were analyzable. The HL at 2 cm had the strongest correlation with V50 (R2 = 0.45; p <0.0001). Other values that were associated with V50 were HL at 3 cm (R2 = 0.37; p = <0.0001), MHD at 2cm (R2 = 0.25; p = 0.0003), MHD at 3 cm (R2 = 0.23; p = 0.0006) and HL at 4 cm (R2 = 0.17, p = 0.0035). The predictive model using HL at 2 cm gave an adjusted R2 = 0.4385 (P<0.0001). Adding other variables into the predictive model did not improve the adjusted R2. The following 3 cutoffs for HL at 2 cm with respective (sensitivity; specificity) were identified: 3.92 cm (0.955; 0.48), 7.65 cm (0.32; 0.48), and 6.5 cm (0.5; 0.8). In the validation cohort, 22/100 had V50% > 10 cc. Validation of the 3 derived cutoffs for HL at 2 cm yielded the following sensitivities and specificities: 1.0 and 0.28 for 3.92 cm; 0.53 and 0.93 for 7.65 cm; 0.58 and 0.69 for 6.5 cm. Positive predictive value (PPV) and negative predictive value (NPV) were as follows: 3.92 cm (PPV = 0.25; NPV = 1.00). 7.65 cm (PPV = 0.63; NPV = 0.89), and 6.5cm (PPV = 0.30; NPV = 0.87). Conclusions: A simple 2-D heart measurement, heart length at 2 cm below the tattoos, had moderate correlation with the irradiated heart volume. Although HL at 2 cm did not have both high specificity and sensitivity to predict who would benefit from DIBH, cut-offs could be selected to maximize sensitivity (3.92 cm for sensitivity 1.0) or specificity (7.65 cm for specificity 0.93). For example, in departments that routinely acquire both free-breathing and DIBH CT simulation scans for all left-sided patients, a cutoff of 3.92cm would minimize the number of unnecessary DIBH scans. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-15.

An Analysis of 3-Dimensional Breast Motion During Normal Respiration: What CTV to PTV Margin Is Needed?

Radiation therapy (RT) for left sided breast cancer is associated with increased risk for cardiovascular disease years after RT. Optimal breast CTV margins with 3D conformal and IMRT however are unclear. Additionally, breast and heart motion may contribute to increased dose that is received by the LAD during RT. In the present study we quantified breast motion during normal respiration for left-sided breast RT using four-dimensional computed tomography (4DCT) and examined motion relative to the heart and left anterior descending artery (LAD).

Dosimetric comparison of left-sided breast radiotherapy treatments: IMRT vs. 3D-CRT

Dosimetric comparison of left-sided breast radiotherapy treatments: IMRT vs. 3D-CRT

Unintended cardiac irradiation during left-sided breast cancer radiotherapy

Cardiac irradiation during left-sided breast radiotherapy may lead to deleterious cardiac side effects. Using image guided radiotherapy, it is possible to exclude the heart from treatment fields and monitor reproducibility of virtual simulation (VS) fields at treatment delivery using electronic portal imaging (EPI). Retrospectively, we evaluate the incidence of cardiac irradiation at VS and subsequent unintended cardiac irradiation during treatment. Patients receiving left-sided radiotherapy to the breast or chest wall, treated with a glancing photon field technique during a four-month period, were included. VS images and EPIs during radiotherapy delivery were visually assessed. The presence of any portion of the heart within the treatment field at VS or during treatment was recorded. Central lung distance and maximum heart distance were recorded. Of 128 patients, 45 (35.1%) had any portion of the heart within the planned treatment field. Of these, inclusion of the heart was clinically unavoidable in 25 (55.6%). Of those with no heart included in the treatment fields at VS, 41 (49.4%) had presence of the heart as assessed on EPI during treatment. Unintended cardiac irradiation during left-sided breast radiotherapy treatment occurs in a sizeable proportion of patients. Despite the use of three-dimensional computed tomography simulation and cardiac shielding, sizeable proportions of patients receiving left-sided breast cancer radiotherapy have unintended cardiac irradiation.

Evaluation of Dose Reduction of Cardiac Exposure Using Deep-inspiration Breath Hold Technique in Left-sided Breast Radiotherapy

Breast cancer is the leading cause of cancer death in women worldwide and the number of women breast cancer patient was increased continuously. Most of breast cancer patie nt has suffered from unnecessary radiation exposure to heart, lung. Low radiation dose to the heart could lead to the worsening of preexisting cardiovascular lesions caused by radiation induced pneumonitis. Also, several statistical reports demonstrated that left-sided breast cancer patient showed higher mortality than right-sided breast cancer patient because of heart disease. In radiation therapy, Deep Inspiration Breath Hold (DIBH) technique which the patient takes a deep inspiration and holds during treatment and could move the heart away from the chest wall and lung, has showed to lead to reduction in cardiac volume and to minimize the unnecessary radiation exposure to heart during treatment. In this study, we investigated the displacement of heart using DIBH CT data compared to free-breathing (FB) CT data and radiation exposure to heart. Treatment planning was performed on the computed tomography (CT) datasets of 10 patients who had received lumpectomy treatments. Heart, lung and both breasts were outlined. The prescribed dose was 50 Gy divided into 28 fractions. The dose distributions in all the plans were required to fulfill the International Commission on Radiation Units and Measurement specifications that include 100% coverage of the CTV with ≥95% of the prescribed dose and that the volume inside the CTV receiving >107% of the prescribed dose should be minimized. Scar boost irradiation was not performed in this study. Displacement of heart was measured by calculating the distance between center of heart and left breast. For the evaluation of radiation dose to heart, minimum, maximum and mean dose to heart were calculated. The present study demonstrates that cardiac dose during left-sided breast radiotherapy can be reduced by applying DIBH breathing control technique.

The deep inspiration breath hold technique using Abches reduces cardiac dose in patients undergoing left-sided breast irradiation

PurposeWe explored whether the deep inspiration breath hold (DIBH) technique using Abches during left-sided breast irradiation was effective for minimizing the amount of radiation to the heart and lung compared to free breathing (FB).Materials and MethodsBetween February and July 2012, a total of 25 patients with left-sided breast cancer underwent two computed tomography scans each with the DIBH using Abches and using FB after breast-conserving surgery. The scans were retrospectively replanned using standardized criteria for the purpose of this study. The DIBH plans for each patient were compared with FB plans using dosimetric parameters.ResultsAll patients were successfully treated with the DIBH technique using Abches. Significant differences were found between the DIBH and FB plans for mean heart dose (2.52 vs. 4.53 Gy), heart V30 (16.48 vs. 45.13 cm3), V20 (21.35 vs. 54.55 cm3), mean left anterior descending coronary artery (LAD) dose (16.01 vs. 26.26 Gy, all p < 0.001), and maximal dose to 0.2 cm3 of the LAD (41.65 vs. 47.27 Gy, p = 0.017). The mean left lung dose (7.53 vs. 8.03 Gy, p = 0.073) and lung V20 (14.63% vs. 15.72%, p = 0.060) of DIBH using Abches were not different significantly compared with FB.ConclusionWe report that the use of a DIBH technique using Abches in breathing adapted radiotherapy for left-sided breast cancer is easily feasible in daily practice and significantly reduces the radiation doses to the heart and LAD, therefore potentially reducing cardiac risk.

Is There an Association Between Left Sided Radiation Therapy and Breast Arterial Calcification on Long-term Cardiac Events in Patients with Breast Cancer?

Purpose: There are multiple studies suggesting association between left sided breast radiation therapy (RT) and increased incidence of coronary artery disease. Most of these studies are older and it is presumed the risk may be lower with modern radiation planning techniques. The aim of this study is to evaluate the association between the left sided RT and cardiac events in patients with breast cancer (BC) who underwent RT in more recent times and also to evaluate if breast arterial calcifications (BAC) seen on mammogram in this cohort of group would predict for cardiac events.

Cardiac Morbidity and Mortality in Women with Ductal Carcinoma In Situ of the Breast Treated with Breast Conservation Therapy

Left-sided breast irradiation has been associated with increased risk of cardiac morbidity and mortality in some studies. This study examines the cardiac toxicity of irradiation in left- versus right-sided patients with ductal carcinoma in situ (DCIS). The medical records of 129 patients with DCIS treated with breast conservation therapy (BCT) at the Moffitt Cancer Center from 1986 to 2002 were reviewed and data regarding subsequent breast cancer and cardiac events were recorded. There were 59 left-sided and 70 right-sided patients treated. Mean age was 55 years. At 8 years, there was no significant difference observed between right- and left-sided breast cancer patients in the development of coronary artery disease, myocardial infarction, congestive heart failure, arrhythmia, valvular disease, cardiomyopathy, or cardiac-related death. Among those patients with left-sided breast cancer, 13.5% of patients developed a cardiovascular event compared to 7% of right-sided patients (p = 0.25). The overall survival at 8 years was 96% and the relapse-free survival was 85%. There were no significant differences in cardiac mortality or morbidity between right- and left-sided DCIS patients treated with BCT. Longer follow-up will be required to ascertain whether late events are more prevalent in left-sided patients.

Respiration Induced Heart Motion and Indications of Gated Delivery for Left-Sided Breast Irradiation

To investigate respiration-induced heart motion for left-sided breast irradiation using a four-dimensional computed tomography (4DCT) technique and to determine novel indications to assess heart motion and identify breast patients who may benefit from a gated treatment. Images of 4DCT acquired during free breathing for 20 left-sided breast cancer patients, who underwent whole breast irradiation with or without regional nodal irradiation, were analyzed retrospectively. Dose distributions were reconstructed in the phases of 0%, 20%, and 50%. The intrafractional heart displacement was measured in three selected transverse CT slices using D(LAD) (the distance from left ascending aorta to a fixed line [connecting middle point of sternum and the body] drawn on each slice) and maximum heart depth (MHD, the distance of the forefront of the heart to the line). Linear regression analysis was used to correlate these indices with mean heart dose and heart dose volume at different breathing phases. Respiration-induced heart displacement resulted in observable variations in dose delivered to the heart. During a normal free-breathing cycle, heart-induced motion D(LAD) and MHD changed up to 9 and 11 mm respectively, resulting in up to 38% and 39% increases of mean doses and V(25.2) for the heart. MHD and D(LAD) were positively correlated with mean heart dose and heart dose volume. Respiratory-adapted gated treatment may better spare heart and ipsilateral-lung compared with the conventional non-gated plan in a subset of patients with large D(LAD) or MHD variations. Proposed indices offer novel assessment of heart displacement based on 4DCT images. MHD and D(LAD) can be used independently or jointly as selection criteria for respiratory gating procedure before treatment planning. Patients with great intrafractional MHD variations or tumor(s) close to the diaphragm may particularly benefit from the gated treatment.

Comparison of dose distributions and organs at risk (OAR) doses in conventional tangential technique (CTT) and IMRT plans with different numbers of beam in left-sided breast cancer

Aim Our aim was to improve dose distribution to the left breast and to determine the dose received by the ipsilateral lung, heart, contralateral lung and contralateral breast during primary left-sided breast irradiation by using intensity modulated radiotherapy (IMRT) techniques compared to conventional tangential techniques (CTT). At the same time, different beams of IMRT plans were compared to each other in respect to CI, HI and organs at risk (OAR) dose. Background Conventional early breast cancer treatment consists of lumpectomy followed by whole breast radiation therapy. CTT is a traditional method used for whole breast radiotherapy and includes standard wedged tangents (two opposed wedged tangential photon beams). The IMRT technique has been widely used for many treatment sites, allowing both improved sparing of normal tissues and more conformal dose distributions. IMRT is a new technique for whole breast radiotherapy. IMRT is used to improve conformity and homogeneity and used to reduce OAR doses. Materials and methods Thirty patients with left-sided breast carcinoma were treated between 2005 and 2008 using 6, 18 or mixed 6/18 MV photons for primary breast irradiation following breast conserving surgery (BCS). The clinical target volume [CTV] was contoured as a target volume and the contralateral breast, ipsilateral lung, contralateral lung and heart tissues as organs at risk (OAR). IMRT with seven beams (IMRT7), nine beams (IMRT9) and 11 beams (IMRT11) plans were developed and compared with CTT and among each other. The conformity index (CI), homogeneity index (HI), and doses to OAR were compared to each other. Results All of IMRT plans significantly improved CI (CTT: 0.76; IMRT7: 0.84; IMRT9: 0.84; IMRT11: 0.85), HI (CTT: 1.16; IMRT7: 1.12; IMRT9: 1.11; IMRT11: 1.11), volume of the ipsilateral lung receiving more than 20 Gy (>V 20 Gy ) (CTT: 14.6; IMRT7: 9.08; IMRT9: 8.10; IMRT11: 8.60), and volume of the heart receiving more than 30 Gy (>V 30 Gy ) (CTT: 6.7; IMRT7: 4.04; IMRT9: 2.80; IMRT11: 2.98) compared to CTT. All IMRT plans were found to significantly decrease >V 20 Gy and >V 30 Gy volumes compared to conformal plans. But IMRT plans increased the volume of OAR receiving low dose radiotherapy: volume of contralateral lung receiving 5 and 10 Gy (CTT: 0.0–0.0; IMRT7: 19.0–0.7; IMRT9: 17.2–0.66; IMRT11: 18.7–0.58, respectively) and volume of contralateral breast receiving 10 Gy (CTT: 0.03; IMRT7: 0.38; IMRT9: 0.60; IMRT11: 0.68). The differences among IMRT plans with increased number of beams were not statistically significant. Conclusion IMRT significantly improved conformity and homogeneity index for plans. Heart and lung volumes receiving high doses were decreased, but OAR receiving low doses was increased.

Cardiac Protection Practices in Routine Conformal Radiotherapy of Left Breast/Chest Wall

Introduction: Meta-analyses of radiotherapy trials have shown the potential for late cardiac toxicity in patients treated with left sided breast radiotherapy. We undertook an audit of left breast cancer patients treated with radiotherapy to evaluate in what proportion of patients part of the heart volume was excluded from the treatment volume by either cardiac shielding or movements of the tangential field borders.

Dosimetric comparison of left-sided whole breast irradiation with 3DCRT, forward-planned IMRT, inverse-planned IMRT, helical tomotherapy, and topotherapy

Background and purposeTo compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques. Materials and methodsTreatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50Gy to 95% of the retracted PTV. ResultsTarget max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT. ConclusionsAll modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.

Abstract P4-11-07: Quantitative Coronary Angiography Findings of Patients Who Received Previous Breast Radiotherapy

Abstract Purpose: To compare the coronary angiographic findings, between patients who had previous left sided breast radiotherapy (RT) and those who had right sided RT. Methods: Between 1995 and 2009, 12696 patients who underwent curative RT for breast cancer in Princess Margaret Hospital were screened to check if they had a post-RT coronary angiogram. Two cardiologists, blinded to treatment, assessed all angiograms and measured the percentage of stenotic lesions and the mean diameter of each segment of the left anterior descending artery (LAD) and the right coronary artery (RCA) using Quantitative Coronary Angiography (QCA). Results: Ninety-one patients were included, 49 and 42 patients had left sided RT and right sided RT respectively. The median time from RT to coronary angiogram was 4.4 years (range: 22 days - 16.9 years). Nineteen patients (39%) in the left sided RT group and 17 (40%) in the right sided RT group needed coronary revascularization (percutaneous coronary intervention or by-pass surgery). The LAD territory was revascularized in 14 (29%) and 11 (26%) patients respectively. The degree of stenoses and mean vessel diameter were not significantly different between the two groups. Table 1: Quantitative The proportion of patients who developed clinically significant stenoses of coronary arteries were not statistically different between the two groups. Table 2: Patiens In 32 patient who had coronary angiograms &amp;gt;5 years after breast RT (16 left-sided and 16 right-sided), the only statistically significant finding (P&amp;lt;0.05) was marginally narrower mid RCA segments among those who had right sided RT: 2.52 mm versus 2.92 mm (P = 0.039). Conclusions: Left sided breast RT did not increase the risk of premature coronary artery disease as compared with right sided RT. However, with the limitation of short duration between radiotherapy and coronary angiogram, late development of coronary artery stenoses 10-15 years after left sided RT can not be excluded. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-07.

Rapid Automated Treatment Planning Process to Select Breast Cancer Patients for Active Breathing Control to Achieve Cardiac Dose Reduction

To evaluate a rapid automated treatment planning process for the selection of patients with left-sided breast cancer for a moderate deep inspiration breath-hold (mDIBH) technique using active breathing control (ABC); and to determine the dose reduction to the left anterior descending coronary artery (LAD) and the heart using mDIBH. Treatment plans were generated using an automated method for patients undergoing left-sided breast radiotherapy (n = 53) with two-field tangential intensity-modulated radiotherapy. All patients with unfavorable cardiac anatomy, defined as having >10 cm(3) of the heart receiving 50% of the prescribed dose (V(50)) on the free-breathing automated treatment plan, underwent repeat scanning on a protocol using a mDIBH technique and ABC. The doses to the LAD and heart were compared between the free-breathing and mDIBH plans. The automated planning process required approximately 9 min to generate a breast intensity-modulated radiotherapy plan. Using the dose-volume criteria, 20 of the 53 patients were selected for ABC. Significant differences were found between the free-breathing and mDIBH plans for the heart V(50) (29.9 vs. 3.7 cm(3)), mean heart dose (317 vs. 132 cGy), mean LAD dose (2,047 vs. 594 cGy), and maximal dose to 0.2 cm(3) of the LAD (4,155 vs. 1,507 cGy, all p <.001). Of the 17 patients who had a breath-hold threshold of ≥ 0.8 L, 14 achieved a ≥ 90% reduction in the heart V(50) using the mDIBH technique. The 3 patients who had had a breath-hold threshold <0.8 L achieved a lower, but still significant, reduction in the heart V(50). A rapid automated treatment planning process can be used to select patients who will benefit most from mDIBH. For selected patients with unfavorable cardiac anatomy, the mDIBH technique using ABC can significantly reduce the dose to the LAD and heart, potentially reducing the cardiac risks.

A Rapid Automated Process for Selection of Breath Hold Technique via Active Breathing Control to Achieve Cardiac Dose Reduction among Patients Receiving Left Sided Breast Irradiation

A Rapid Automated Process for Selection of Breath Hold Technique via Active Breathing Control to Achieve Cardiac Dose Reduction among Patients Receiving Left Sided Breast Irradiation

Dosimetric Comparison of Left-sided Whole Breast Irradiation with 3DCRT, Segmental IMRT, Helical Tomotherapy, Topotherapy, and IMPT

Dosimetric Comparison of Left-sided Whole Breast Irradiation with 3DCRT, Segmental IMRT, Helical Tomotherapy, Topotherapy, and IMPT

Six-year Experience Routinely Utilizing Moderate Deep Inspiration Breath-hold (mDIBH) for Reduction of Cardiac Dose in Left-sided Breast Irradiation for Patients with Both Early-stage and Locally-advanced Breast Cancer

Six-year Experience Routinely Utilizing Moderate Deep Inspiration Breath-hold (mDIBH) for Reduction of Cardiac Dose in Left-sided Breast Irradiation for Patients with Both Early-stage and Locally-advanced Breast Cancer

Comparison of Predicted Cardiac Mortality and Lung Pneumonitis Risks for Left-sided Whole Breast Irradiation with 3DCRT versus Helical Tomotherapy

Comparison of Predicted Cardiac Mortality and Lung Pneumonitis Risks for Left-sided Whole Breast Irradiation with 3DCRT versus Helical Tomotherapy

Postoperative Irradiation of Left-Sided Breast Cancer Patients and Cardiac Toxicity

To evaluate the impact of deep inspiration breath-hold (DIBH) technique during postoperative left-sided tangential breast irradiation on minimizing irradiated heart amount compared to normal breathing. In 22 patients with left-sided breast cancer, postoperative CT scanning was performed in different respiratory phases using the Varian Real-time Position Management System™ for monitoring of respiratory chest wall motion. Each patient underwent two CT scans: during normal breathing and DIBH. For each scan, an optimized plan was designed with tangential photon fields encompassing the clinical target volume after breast-conserving surgery or modified radical mastectomy. The resulting dose-volume histograms were compared between both breathing techniques for irradiated volume and dose to the heart. The mean patient age was 51 years (range: 34–77 years). The DIBH-gated technique was well accepted by all patients. The significant reduction in dose to the irradiated heart volume for the DIBH technique compared to the normal breathing was 56% (mean heart dose: 2.3 Gy vs. 1.3 Gy; p = 0.01). This study demonstrates that irradiated cardiac volumes can significantly be reduced in left-sided breast cancer patients using DIBH technique for postoperative tangential radiotherapy. Moreover, the technique is safe and feasible in daily routine.