Radiation dose-volume effects in the heart

Clinical experience using a video-guided spirometry system for deep inhalation breath-hold radiotherapy of left-sided breast cancer

The purpose was to report clinical experience of a video-guided spirometry system in applying deep inhalation breath-hold (DIBH) radiotherapy for left-sided breast cancer, and to study the systematic and random uncertainties, intra- and interfraction motion and impact on cardiac dose associated with DIBH. The data from 28 left-sided breast cancer patients treated with spirometer-guided DIBH radiation were studied. Dosimetric comparisons between free-breathing (FB) and DIBH plans were performed. The distance between the heart and chest wall measured on the digitally reconstructed radiographs (DRR) and MV portal images, dDRR(DIBH) and dport(DIBH), respectively, was compared as a measure of DIBH setup uncertainty. The difference (Δd) between dDRR(DIBH) and dport(DIBH) was defined as the systematic uncertainty. The standard deviation of Δd for each patient was defined as the random uncertainty. MV cine images during radiation were acquired. Affine registrations of the cine images acquired during one fraction and multiple fractions were performed to study the intra- and interfraction motion of the chest wall. The median chest wall motion was used as the metric for intra- and interfraction analysis. Breast motions in superior-inferior (SI) direction and "AP" (defined on the DRR or MV portal image as the direction perpendicular to the SI direction) are reported. Systematic and random uncertainties of 3.8 mm and 2mm, respectively, were found for this spirometer-guided DIBH treatment. MV cine analysis showed that intrafraction chest wall motions during DIBH were 0.3mm in "AP" and 0.6 mm in SI. The interfraction chest wall motions were 3.6 mm in "AP" and 3.4 mm in SI. Utilization of DIBH with this spirometry system led to a statistically significant reduction of cardiac dose relative to FB treatment. The DIBH using video-guided spirometry provided reproducible cardiac sparing with minimal intra- and interfraction chest wall motion, and thus is a valuable adjunct to modern breast treatment techniques.

Recommendations for cardiomyopathy surveillance for survivors of childhood cancer: a report from the International Late Effects of Childhood Cancer Guideline Harmonization Group

Survivors of childhood cancer treated with anthracycline chemotherapy or chest radiation are at an increased risk of developing congestive heart failure. In this population, congestive heart failure is well recognised as a progressive disorder, with a variable period of asymptomatic cardiomyopathy that precedes signs and symptoms. As a result, several clinical practice guidelines have been developed independently to help with detection and treatment of asymptomatic cardiomyopathy. These guidelines differ with regards to definitions of at-risk populations, surveillance modality and frequency, and recommendations for interventions. Differences between these guidelines could hinder the effective implementation of these recommendations. We report on the results of an international collaboration to harmonise existing cardiomyopathy surveillance recommendations using an evidence-based approach that relied on standardised definitions for outcomes of interest and transparent presentation of the quality of the evidence. The resultant recommendations were graded according to the quality of the evidence and the potential benefit gained from early detection and intervention.

Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose

Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dose and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V(20 Gy)), heart volume percentage receiving at least 25 Gy (V(25 Gy)). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p < 0.001). The volume of tissue receiving ≥ 105% of the prescription dose was higher in the electron-only (mean = 69.7 ± 56.1 cm(3)) as opposed to combined photon-electron (mean = 50.8 ± 40.9 cm(3)) and photon-only beams (mean = 32.2 ± 28.1 cm(3), p = 0.114). Heart V(25 Gy) was not statistically different among the plans (p = 0.999). Total lung V(20 Gy) was lowest in electron-only (mean = 10.9 ± 2.3%) followed by combined photon-electron (mean = 13.8 ± 2.3%) and highest in photon-only plans (mean = 16.2 ± 3%, p < 0.001). As expected, photon-only plans demonstrated the highest target coverage and total lung V(20 Gy). The superiority of electron-only beams, in terms of decreasing lung dose, is set back by the dosimetric hotspots associated with such plans. Combined photon-electron treatment is a feasible technique for supraclavicular nodal irradiation and results in adequate target coverage, acceptable dosimetric hotspot volume, and slightly reduced lung dose.

The cardiac dose-sparing benefits of deep inspiration breath-hold in left breast irradiation: a systematic review

Introduction

Despite technical advancements in breast radiation therapy, cardiac structures are still subject to significant levels of irradiation. As the use of adjuvant radiation therapy after breast-conserving surgery continues to improve survival for early breast cancer patients, the associated radiation-induced cardiac toxicities become increasingly relevant. Our primary aim was to evaluate the cardiac-sparing benefits of the deep inspiration breath-hold (DIBH) technique.

Methods

An electronic literature search of the PubMed database from 1966 to July 2014 was used to identify articles published in English relating to the dosimetric benefits of DIBH. Studies comparing the mean heart dose of DIBH and free breathing treatment plans for left breast cancer patients were eligible to be included in the review. Studies evaluating the reproducibility and stability of the DIBH technique were also reviewed.

Results

Ten studies provided data on the benefits of DIBH during left breast irradiation. From these studies, DIBH reduced the mean heart dose by up to 3.4 Gy when compared to a free breathing approach. Four studies reported that the DIBH technique was stable and reproducible on a daily basis. According to current estimates of the excess cardiac toxicity associated with radiation therapy, a 3.4 Gy reduction in mean heart dose is equivalent to a 13.6% reduction in the projected increase in risk of heart disease.

Conclusion

DIBH is a reproducible and stable technique for left breast irradiation showing significant promise in reducing the late cardiac toxicities associated with radiation therapy.

Acute effects of chemoradiation on cardiac function in oesophageal cancer: a MUGA scan and echo-based study

OBJECTIVE

To study the acute effects of concurrent chemoradiation on global and regional cardiac contractility and correlate with radiation dose.

METHODS

16 patients of locally advanced oesophageal squamous cell carcinoma were serially followed up with multiple-gated acquisition (MUGA) scans and echocardiograms during the course of concurrent chemoradiation to evaluate the ejection fractions (EFs) and pericardial status, respectively. Changes in cardiac contractility were correlated with the doses received by the heart.

RESULTS

Concurrent chemoradiation resulted in a significant reduction in the contractility of both left ventricle (LV) and right ventricle (RV), with a mean reduction of LVEF by 5.6% and RVEF by 6.5% over the course of treatment, which had a significant correlation with the radiation doses received by the ventricles (p=0.001). On further analysis, correlation between radiation dose and decrease in contractility was more significant in the boost phase (16 Gy in 8 fractions over one and a half weeks; p=0.001 for LV and p=0.008 for RV) compared with the initial phase (40 Gy in 20 fractions over 4 weeks; p=0.184 for LV and p=0.269 for RV). One out of 16 patients developed mild acute pericarditis.

CONCLUSIONS

Concurrent chemoradiation resulted in acute decrease in EF of both ventricles in a dose-dependent manner. Correlation between cardiac doses and decrease in EF was more marked in the boost phase, suggesting a possible threshold of 40 Gy for this impairment. Nevertheless, conclusions regarding this possible threshold need to be interpreted with caution given the small sample size.

Active Breathing Coordinator reduces radiation dose to the heart and preserves local control in patients with left breast cancer: report of a prospective trial

PURPOSE

Incidental radiation dose to the heart and lung during breast radiation therapy (RT) has been associated with an increased risk of cardiopulmonary morbidity. We conducted a prospective trial to determine if RT with the Active Breathing Coordinator (ABC) can reduce the mean heart dose (MHD) by ≥20% and dose to the lung.

METHODS AND MATERIALS

Patients with stages 0-III left breast cancer (LBC) were enrolled and underwent simulation with both free breathing (FB) and ABC for comparison of dosimetry. ABC was used during the patient's RT course if the MHD was reduced by ≥5%. The median prescription dose was 50.4 Gy plus a boost in 77 patients (90%). The primary endpoint was the magnitude of MHD reduction when comparing ABC to FB. Secondary endpoints included dose reduction to the heart and lung, procedural success rate, and adverse events.

RESULTS

A total of 112 patients with LBC were enrolled from 2002 to 2011 and 86 eligible patients underwent both FB and ABC simulation. Ultimately, 81 patients received RT using ABC, corresponding to 72% procedural success. The primary endpoint was achieved as use of ABC reduced MHD by 20% or greater in 88% of patients (P < .0001). The median values for absolute and relative reduction in MHD were 1.7 Gy and 62%, respectively. RT with ABC provided a statistically significant dose reduction to the left lung. After a median follow up of 81 months, 8-year estimates of locoregional relapse, disease-free, and overall survival were 7%, 90%, and 96%, respectively.

CONCLUSIONS

ABC was well tolerated and significantly reduced MHD while preserving local control. Use of the ABC device during RT should be considered to reduce the risk of ischemic heart disease in populations at risk.

Feasibility and efficacy of simultaneous integrated boost intensity-modulated radiation therapy in patients with limited-disease small cell lung cancer

PURPOSE

To evaluate the feasibility and efficacy of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) in patients with limited-disease small-cell lung cancer (LD-SCLC).

METHODS

Patients with LD-SCLC were treated with SIB-IMRT within 1 week after completion of 2 cycles of induction chemotherapy. Then 2-4 cycles of adjuvant chemotherapy were administered within 1 week after SIB-IMRT. Irradiation was given accelerated hyper-fractionated with the prescribed dose 57Gy at 1.9Gy twice daily to the gross tumor volume (GTV) , 51Gy at 1.7Gy twice daily to the clinical tumor volume (CTV) and 45Gy at 1.5Gy twice daily to the planning target volume (PTV). The chemotherapy regimen consisted of platinum plus etoposide. Prophylactic cranial radiation (25Gy in 10 fractions) was administered to patients who got complete response (CR) or near complete response (nCR). The primary endpoint of this study was the frequency of grade 3 or higher acute non-hematologic treatment-related toxicities. Secondary end points included objective response, overall survival (OS), progression-free survival (PFS), locoregional recurrence-free survival (LRFS).

RESULTS

A cohort of 35 patients were enrolled in the study, the biological equivalent dose (BED) of the GTV in the SIB-IMRT was 59.16Gy. Grade 1, 2, and 3 esophagitis were observed in 11 (31%), 12 (34%), and 6 (17%) patients, respectively; Grade 1 and 2 pneumonitis were observed in 8 (23%) and 4 (11%) patients, respectively. The median OS and PFS of the whole group were 37.7 months and 29.3 months, respectively. The 1- and 2-year OS was 94.1% and 68.5%, respectively. The 1- and 2-year PFS was 76.8% and 40.7%, respectively. The 1- and 2-year LRFS was 87.7% and 73.8%, respectively.

CONCLUSIONS

SIB-IMRT was feasible and well-tolerated in patients with LD-SCLC, and worth further evaluating in a large prospective clinical trial.

Delayed primary excision with subsequent modification of radiotherapy dose for intermediate-risk rhabdomyosarcoma: a report from the Children's Oncology Group Soft Tissue Sarcoma Committee

The majority of intermediate-risk rhabdomyosarcoma (RMS) patients have gross residual disease (Group III) after their first operative procedure. It is currently not known if local control rates can be maintained when, following induction chemotherapy, the radiation therapy (RT) dose is decreased after a delayed primary excision (DPE). To answer this question we evaluated patients enrolled on COG D9803 (1999-2005) who had Group III tumors of the bladder dome, extremity or trunk (thorax, abdomen and pelvis) were candidates for DPE at Week 12 if the primary tumor appeared resectable. RT dose was then adjusted by the completeness of DPE: no evidence of disease 36 Gy, microscopic residual 41.4 Gy and gross residual disease (GRD) 50.4 Gy. A total of 161 Group III patients were evaluated (24 bladder dome, 63 extremity and 74 trunk). Seventy-three patients (45%) underwent DPE which achieved removal of all gross disease in 61 (84%) who were then eligible for reduced RT dose (43/73 received 36 Gy, 19/73 received 41.4 Gy). The local 5-year failure rate (0% for bladder dome, 7% for extremity and 20% for trunk) was similar to IRS-IV, which did not encourage DPE and did not allow for DPE adapted RT dose reduction. In conclusion, DPE was performed in 45% of Group III RMS patients with tumors at select anatomic sites (bladder dome, extremity and trunk) and 84% of those who had DPE were eligible for RT dose reduction. Local control outcomes were similar to historic results with RT alone.

Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

The impact of inter-fraction set-up errors on the probability of pulmonary and cardiac complication in left-sided breast cancer patients

Purpose

This study evaluated the impact of patient set-up errors on the probability of pulmonary and cardiac complications in the irradiation of left-sided breast cancer.

Methods and materials

Using the CMS XiO Version 4·6 radiotherapy planning system's normal tissue complication probability (NTCP) algorithm and the Lyman–Kutcher–Burman model, we calculated the dose–volume histograms (DVH) indices for the ipsilateral lung and heart and the resultant NTCP for radiation-induced pneumonitis and excess cardiac mortality in 12 left-sided breast cancer patients.

Results

Isocentric shifts in the posterior direction had the greatest effect on the lung V20, heart V25, and mean and maximum doses to the lung and the heart. DVH results show that the ipsilateral lung V20 tolerance was exceeded in 58% of the patients after 1 cm posterior shifts. Similarly, the heart V25 tolerance was exceeded after 1 cm antero-posterior and left–right isocentric shifts in 70% of the patients. The baseline NTCPs for radiation-induced pneumonitis ranged from 0·73% to 3·4%, with a mean value of 1·7%. The maximum reported NTCP for radiation-induced pneumonitis was 5·8% (mean 2·6%) after 1 cm posterior isocentric shift. The NTCP for excess cardiac mortality were 0% in 100% of the patients (n = 12) before and after set-up error simulations.

Conclusions

Set-up errors in left-sided breast cancer patients have a statistically significant impact on the Lung NTCPs and DVH indices. However, with a central lung distance of 3 cm or less (CLD < 3 cm), and a maximum heart distance of 1·5 cm or less (MHD < 1·5 cm), the treatment plans could tolerate set-up errors of up to 1 cm without any change in the NTCP to the heart.

Complication probability models for radiation-induced heart valvular dysfunction: do heart-lung interactions play a role?

Purpose

The purpose of this study is to compare different normal tissue complication probability (NTCP) models for predicting heart valve dysfunction (RVD) following thoracic irradiation.

Methods

All patients from our institutional Hodgkin lymphoma survivors database with analyzable datasets were included (n = 90). All patients were treated with three-dimensional conformal radiotherapy with a median total dose of 32 Gy. The cardiac toxicity profile was available for each patient. Heart and lung dose-volume histograms (DVHs) were extracted and both organs were considered for Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) NTCP model fitting using maximum likelihood estimation. Bootstrap refitting was used to test the robustness of the model fit. Model performance was estimated using the area under the receiver operating characteristic curve (AUC).

Results

Using only heart-DVHs, parameter estimates were, for the LKB model: D₅₀ = 32.8 Gy, n = 0.16 and m = 0.67; and for the RS model: D₅₀ = 32.4 Gy, s = 0.99 and γ = 0.42. AUC values were 0.67 for LKB and 0.66 for RS, respectively. Similar performance was obtained for models using only lung-DVHs (LKB: D₅₀ = 33.2 Gy, n = 0.01, m = 0.19, AUC = 0.68; RS: D₅₀ = 24.4 Gy, s = 0.99, γ = 2.12, AUC = 0.66). Bootstrap result showed that the parameter fits for lung-LKB were extremely robust. A combined heart-lung LKB model was also tested and showed a minor improvement (AUC = 0.70). However, the best performance was obtained using the previously determined multivariate regression model including maximum heart dose with increasing risk for larger heart and smaller lung volumes (AUC = 0.82).

Conclusions

The risk of radiation induced valvular disease cannot be modeled using NTCP models only based on heart dose-volume distribution. A predictive model with an improved performance can be obtained but requires the inclusion of heart and lung volume terms, indicating that heart-lung interactions are apparently important for this endpoint.

Serum biomarkers for the detection of cardiac toxicity after chemotherapy and radiation therapy in breast cancer patients

Multi-modality cancer treatments that include chemotherapy, radiation therapy, and targeted agents are highly effective therapies. Their use, especially in combination, is limited by the risk of significant cardiac toxicity. The current paradigm for minimizing cardiac morbidity, based on serial cardiac function monitoring, is suboptimal. An alternative approach based on biomarker testing, has emerged as a promising adjunct and a potential substitute to routine echocardiography. Biomarkers, most prominently cardiac troponins and natriuretic peptides, have been evaluated for their ability to describe the risk of potential cardiac dysfunction in clinically asymptomatic patients. Early rises in cardiac troponin concentrations have consistently predicted the risk and severity of significant cardiac events in patients treated with anthracycline-based chemotherapy. Biomarkers represent a novel, efficient, and robust clinical decision tool for the management of cancer therapy-induced cardiotoxicity. This article aims to review the clinical evidence that supports the use of established biomarkers such as cardiac troponins and natriuretic peptides, as well as emerging data on proposed biomarkers.

Clinical evaluation of X-ray voxel Monte Carlo versus pencil beam-based dose calculation in stereotactic body radiotherapy of lung cancer under normal and deep inspiration breath hold

The purpose of this study is to evaluate the differences between dose distributions calculated with the pencil beam (PB) and X-ray voxel Monte Carlo (MC) algorithms for patients with lung cancer using intensity-modulated radiotherapy (IMRT) or HybridArc techniques. The 2 algorithms were compared in terms of dose-volume histograms, under normal and deep inspiration breath hold, and in terms of the tumor control probability (TCP). The dependence of the differences in tumor volume and location was investigated. Dosimetric validation was performed using Gafchromic EBT3 (International Specialty Products, ISP, Wayne, NJ). Forty-five Computed Tomography (CT) data sets were used for this study; 40 Gy at 8 Gy/fraction was prescribed with 5 noncoplanar 6-MV IMRT beams or 3 to 4 dynamic conformal arcs with 3 to 5 IMRT beams distributed per arc. The plans were first calculated with PB and then recalculated with MC. The difference between the mean tumor doses was approximately 10% ± 4%; these differences were even larger under deep inspiration breath hold. Differences between the mean tumor dose correlated with tumor volume and path length of the beams. The TCP values changed from 99.87% ± 0.24% to 96.78% ± 4.81% for both PB- and MC-calculated plans (P = .009). When a fraction of hypoxic cells was considered, the mean TCP values changed from 76.01% ± 5.83% to 34.78% ± 18.06% for the differently calculated plans (P < .0001). When the plans were renormalized to the same mean dose at the tumor, the mean TCP for oxic cells was 99.05% ± 1.59% and for hypoxic cells was 60.20% ± 9.53%. This study confirms that the MC algorithm adequately accounts for inhomogeneities. The inclusion of the MC in the process of IMRT optimization could represent a further step in the complex problem of determining the optimal treatment plan.

Novel radiotherapy techniques for involved-field and involved-node treatment of mediastinal Hodgkin lymphoma: when should they be considered and which questions remain open?

PURPOSE

Hodgkin lymphoma (HL) is a highly curable disease. Reducing late complications and second malignancies has become increasingly important. Radiotherapy target paradigms are currently changing and radiotherapy techniques are evolving rapidly.

DESIGN

This overview reports to what extent target volume reduction in involved-node (IN) and advanced radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy-compared with involved-field (IF) and 3D radiotherapy (3D-RT)- can reduce high doses to organs at risk (OAR) and examines the issues that still remain open.

RESULTS

Although no comparison of all available techniques on identical patient datasets exists, clear patterns emerge. Advanced dose-calculation algorithms (e.g., convolution-superposition/Monte Carlo) should be used in mediastinal HL. INRT consistently reduces treated volumes when compared with IFRT with the exact amount depending on the INRT definition. The number of patients that might significantly benefit from highly conformal techniques such as IMRT over 3D-RT regarding high-dose exposure to organs at risk (OAR) is smaller with INRT. The impact of larger volumes treated with low doses in advanced techniques is unclear. The type of IMRT used (static/rotational) is of minor importance. All advanced photon techniques result in similar potential benefits and disadvantages, therefore only the degree-of-modulation should be chosen based on individual treatment goals. Treatment in deep inspiration breath hold is being evaluated. Protons theoretically provide both excellent high-dose conformality and reduced integral dose.

CONCLUSION

Further reduction of treated volumes most effectively reduces OAR dose, most likely without disadvantages if the excellent control rates achieved currently are maintained. For both IFRT and INRT, the benefits of advanced radiotherapy techniques depend on the individual patient/target geometry. Their use should therefore be decided case by case with comparative treatment planning.

A dosimetry study precisely outlining the heart substructure of left breast cancer patients using intensity-modulated radiation therapy

The purpose of this study was to evaluate the feasibility of delineating the substructure of the heart by using 64‐slice spiral CT coronary angiography (CTA) in breast cancer patients who underwent left breast‐conserving surgery, and to compare the dosimetric differences between the targets and organs at risk in the prone and supine positions in intensity‐modulated radiation therapy (IMRT) planning. From January to December 2011, ten patients who underwent left breast‐conserving surgery were enrolled in this study. CTA was performed in both the supine and prone positions during the simulation, and conventional scanning without CTA was performed at the same time. Image registration was performed for paired image series using a commercially available planning system. In a conventional image series, the clinical target volume (CTV) of the whole breast, planning target volume (PTV), bilateral lungs (L‐Lung, R‐Lung), spinal cord, contralateral breast (R‐Breast), and heart were delineated. In the CTA image series, the left ventricular (LV) and left anterior descending coronary arteries (LAD) and the planning risk volume (LAD‐PRV) of the LAD (LAD with a 1 cm margin) were outlined. For each patient, two separate IMRT plans were developed for the supine and prone positions. A total of 20 plans were generated. The following indicators were compared: Dmean and D95 for the PTV; Dmean, V5, and V20 for the left lung; Dmean, V10, V20, V25, V30, and V40 for the heart and its substructures (LAD‐PRV, LV); Dmean and V5 for the right lung; and Dmax and Dmean for the right breast. Using CTA to delineate the substructures of the heart is simple and straightforward. Plans for both the prone and supine positions reached the prescribed dose for the PTV without significant differences. Dose distributions were acceptable for both the prone and supine positions. However, the LAD‐PRV, LV, heart, and L‐Lung received smaller doses in the prone position plans than in the supine position plans. The Dmean values reduced by 445.83cGy(p=0.043),575.00cGy(p=0.003),402.00cGy(p=0.039), and 553.33cGy(p=0.004) in the LAD‐PRV, LV, heart, and L‐Lung. In addition, the V25 lessened 12.54%(p=0.042) and 8.70%(p=0.019) in the LV and heart, while the V20 was decreased 8.57%(p=0.042),15.21%(p=0.026),12.59%(p=0.011), and 10.62%(p=0.006) in the LAD‐PRV, LV, heart, and L‐Lung, respectively. Similarly, the V10 and V30 were reduced by 28.31% (p=0.029) and 5.54%(p=0.034) in the heart, while the V5 was cut back 27.86%(p=0.031) in the L‐Lung. For most Asian women with average‐sized breasts after breast conserving treatment (BCT), prone positioning during IMRT radiation will reduce the dose to the ipsilateral lung, heart, and substructures of the heart, which may reduce the incidence of cardiovascular events after radiotherapy more than radiation therapy performed in a supine position. Using CTA to delineate the substructures of the heart is easy and intuitive. It is cost‐effective and highly recommended for breast cancer IMRT. However, the dose‐volume limits of the heart substructures remain to be determined.

PACS number: 87.55.dk

Current strategies in chemoradiation for esophageal cancer

Chemoradiotherapy (CRT) has an important role in the treatment of esophageal cancer in both the inoperable and the pre-operative settings. Pre-operative chemoradiation therapy is generally given to 41.4-50.4 Gy with platinum or paclitaxel based chemotherapy. The most common definitive dose in the U.S. is 50-50.4 Gy. New advances in CRT for esophageal cancer have come from looking for ways to minimize toxicity and maximize efficacy. Recent investigations for minimizing toxicity have focused advanced radiation techniques such as IMRT and proton therapy, have sought to further define normal tissue tolerances, and have examined the use of tighter fields with less elective clinical target volume coverage. Efforts to maximize efficacy have included the use of early positron emission tomography (PET) response directed therapy, molecularly targeted therapies, and the use of tumor markers that predict response.

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.

Adjuvant chemotherapy and radiotherapy in the treatment of non-small cell lung cancer (NSCLC)

Lung cancer is one of the most common human malignancies and remains the leading cause of cancer related deaths worldwide. Many recent technological advances led to improved diagnostics and staging of lung cancer. With development of new treatment options such as targeted therapies there might be improvement in progression free survival of patients with advanced stage non-small cell lung cancer (NSCLC). Improvement in overall survival is still reserved for selected patients and selected treatments. One of the mostly investigated therapeutic options is adjuvant treatment. There are many open issues in selection of patients and administration of appropriate adjuvant treatment.

Cardiovascular disease after cancer therapy

Improvements in treatment and earlier diagnosis have both contributed to increased survival for many cancer patients. Unfortunately, many treatments carry a risk of late effects including cardiovascular diseases (CVDs), possibly leading to significant morbidity and mortality. In this paper we describe current knowledge of the cardiotoxicity arising from cancer treatments, outline gaps in knowledge, and indicate directions for future research and guideline development, as discussed during the 2014 Cancer Survivorship Summit organised by the European Organisation for Research and Treatment of Cancer (EORTC). Better knowledge is needed of the late effects of modern systemic treatments and of radiotherapy to critical structures of the heart, including the effect of both radiation dose and volume of the heart exposed. Research elucidating the extent to which treatments interact in causing CVD, and the mechanisms involved, as well as the extent to which treatments may increase CVD indirectly by increasing cardiovascular risk factors is also important. Systematic collection of data relating treatment details to late effects is needed, and great care is needed to obtain valid and generalisable results. Better knowledge of these cardiac effects will contribute to both primary and secondary prevention of late complications where exposure to cardiotoxic treatment is unavoidable. Also surrogate markers would help to identify patients at increased risk of cardiotoxicity. Evidence-based screening guidelines for CVD following cancer are also needed. Finally, risk prediction models should be developed to guide primary treatment choice and appropriate follow up after cancer treatment.

Volumetric modulated arc therapy and breath-hold in image-guided locoregional left-sided breast irradiation

PURPOSE

To investigate the effects of using volumetric modulated arc therapy (VMAT) and/or voluntary moderate deep inspiration breath-hold (vmDIBH) in the radiation therapy (RT) of left-sided breast cancer including the regional lymph nodes.

MATERIALS AND METHODS

For 13 patients, four treatment combinations were compared; 3D-conformal RT (i.e., forward IMRT) in free-breathing 3D-CRT(FB), 3D-CRT(vmDIBH), 2 partial arcs VMAT(FB), and VMAT(vmDIBH). Prescribed dose was 42.56 Gy in 16 fractions. For 10 additional patients, 3D-CRT and VMAT in vmDIBH only were also compared.

RESULTS

Dose conformity, PTV coverage, ipsilateral and total lung doses were significantly better for VMAT plans compared to 3D-CRT. Mean heart dose (D(mean,heart)) reduction in 3D-CRT(vmDIBH) was between 0.9 and 8.6 Gy, depending on initial D(mean,heart) (in 3D-CRT(FB) plans). VMAT(vmDIBH) reduced the D(mean,heart) further when D(mean,heart) was still >3.2 Gy in 3D-CRT(vmDIBH). Mean contralateral breast dose was higher for VMAT plans (2.7 Gy) compared to 3DCRT plans (0.7 Gy).

CONCLUSIONS

VMAT and 3D-CRT(vmDIBH) significantly reduced heart dose for patients treated with locoregional RT of left-sided breast cancer. When Dmean,heart exceeded 3.2 Gy in 3D-CRT(vmDIBH) plans, VMAT(vmDIBH) resulted in a cumulative heart dose reduction. VMAT also provided better target coverage and reduced ipsilateral lung dose, at the expense of a small increase in the dose to the contralateral breast.

Advanced radiotherapy techniques for breast cancer to minimize cardiovascular risk

SUMMARY 

Radiotherapy plays an integral role in the management of breast cancer and has been demonstrated to reduce the risk of recurrence and improve overall survival. Recent reports in the literature have suggested a dose-dependent risk of cardiovascular disease following radiation treatment for breast cancer. This article highlights new advances in radiotherapy for breast cancer that may help minimize radiotherapy doses to the heart.

Dose-escalation study for cardiac radiosurgery in a porcine model

PURPOSE

To perform a proof-of-principle dose-escalation study to radiosurgically induce scarring in cardiac muscle tissue to block veno-atrial electrical connections at the pulmonary vein antrum, similar to catheter ablation.

METHODS AND MATERIALS

Nine mini-pigs underwent pretreatment magnetic resonance imaging (MRI) evaluation of heart function and electrophysiology assessment by catheter measurements in the right superior pulmonary vein (RSPV). Immediately after examination, radiosurgery with randomized single-fraction doses of 0 and 17.5-35 Gy in 2.5-Gy steps were delivered to the RSPV antrum (target volume 5-8 cm(3)). MRI and electrophysiology were repeated 6 months after therapy, followed by histopathologic examination.

RESULTS

Transmural scarring of cardiac muscle tissue was noted with doses ≥32.5 Gy. However, complete circumferential scarring of the RSPV was not achieved. Logistic regressions showed that extent and intensity of fibrosis significantly increased with dose. The 50% effective dose for intense fibrosis was 31.3 Gy (odds ratio 2.47/Gy, P<.01). Heart function was not affected, as verified by MRI and electrocardiogram evaluation. Adjacent critical structures were not damaged, as verified by pathology, demonstrating the short-term safety of small-volume cardiac radiosurgery with doses up to 35 Gy.

CONCLUSIONS

Radiosurgery with doses >32.5 Gy in the healthy pig heart can induce circumscribed scars at the RSPV antrum noninvasively, mimicking the effect of catheter ablation. In our study we established a significant dose-response relationship for cardiac radiosurgery. The long-term effects and toxicity of such high radiation doses need further investigation in the pursuit of cardiac radiosurgery for noninvasive treatment of atrial fibrillation.

VMAT techniques for lymph node-positive left sided breast cancer

PURPOSE

To investigate the plan quality of two different volumetric modulated arc therapy (VMAT) techniques for lymph node-positive left-sided breast cancer.

METHODS

Two VMAT plans were generated for 10 lymph node-positive left-sided breast cancer patients: one plan using one single segment of a full rotation, typically an arc segment of 230° (1s-VMAT); and a second plan consisting of 2 small tangential arc segments of about 50° (2s-VMAT). For plan comparison, various dose and dose volume metrics (Dmean, D98%, D2% for target volumes, D2%, Dmean and Vx% for organs at risk (OAR)) were evaluated.

RESULTS

Both techniques fulfilled both clinical target dose and OAR goals. 1s-VMAT achieved a slightly better homogeneity and better target coverage (D2%= 54.2 ± 0.7 Gy, D98%= 30.3 ± 1.8 Gy) compared to 2s-VMAT (D2%= 55.0 ± 1.1 Gy, D98%= 29.9 ± 1.7 Gy). For geometrical reasons, OAR sparing was noticeable but not significant better using 2s-VMAT, particularly heart and contralateral breast. The heart received a mean dose of 4.4 ± 0.8 Gy using 1s-VMAT and 3.3 ± 1.0 Gy using 2s-VMAT; the contralateral breast received 1.5 ± 0.3 Gy and 0.9 ± 0.3 Gy, respectively.

CONCLUSIONS

A VMAT technique based on two small tangential arc segments enables improved OAR sparing; the differences between the two techniques in target coverage and homogeneity are minor. Patient age and -anatomy must be considered for each individual case when deciding which technique to be used.

Comparison of Chest Wall and Lymphatic Radiotherapy Techniques in Patients with Left Breast Carcinoma

OBJECTIVE

The aim of this study was to find the most appropriate technique for postmastectomy chest wall (CW) and lymphatic irradiation.

MATERIALS AND METHODS

Partially wide tangent, 30/70 photon/electron mix, 20/80 photon/electron mix and CW and internal mammary en face electron field, were studied on computerized tomography (CT) scans of 10 left breast carcinoma patients and dosimetric calculations have been studied. Dose volume histograms (DVH) obtained from treatment planning system (TPS) were used for minimal, maximal and mean doses received by the clinical target volumes and critical structures.

RESULTS

Partially wide tangent field resulted in the most homogeneous dose distribution for the CW and a significantly lower lung and heart doses compared with all other techniques. However, right breast dose was significantly higher for partially wide tangent technique than that each of the other techniques. Approximately 0.6-7.9% differences were found between thermoluminescent dosimeter (TLD) and treatment planning system (TPS). The daily surface doses calculating using Gafchromic® external beam therapy (EBT) dosimetry films were 161.8±2.7 cGy for the naked, 241.0±1.5 cGy when 0.5 cm bolus was used and 255.3±2.7 cGy when 1 cm bolus was used.

CONCLUSION

As a result of this study, partially wide tangent field was found to be the most appropriate technique in terms of the dose distribution, treatment planning and set-up procedure. The main disadvantage of this technique was the higher dose to the contralateral breast comparing the other techniques.

[Radiation therapy of cardiac sarcomas]

PURPOSE

Primary cardiac sarcomas represent less than 10 yearly cases in France. Their median survival is approximately 18 months. The treatment consists of surgery when possible. The role of chemotherapy and radiation therapy is controversial, especially with respect to limiting cardiac radiation dose that is theoretically incompatible with the requirement of a tumoricidal dose for sarcoma. A recent series of 124 cases of the French Sarcoma Group suggested a benefit of radiation therapy on progression-free survival.

PATIENTS AND METHODS

The dosimetric data of 12 patients were analyzed.

RESULTS

There was variety in radiotherapy modalities and definition of target volumes, doses and techniques are evolving more conformal plans. Irradiation appeared feasible with conventional fractionation with respect to toxicities (although probably underestimated due to short follow-up and dismal prognosis) and previously demonstrated benefit of radiotherapy for primitive cardiac sarcomas.

CONCLUSION

A scheme of 45Gy in 1.8Gy per fraction to a preoperative volume with an additional dose of 14Gy in 7 fractions on areas at risk or residual disease and margins 1cm, may be proposed based on the preliminary data of this study. Intensity modulated radiotherapy with daily cone-beam CT-scanner should be evaluated.

Therapeutic radiation dose delivered to the low axilla during whole breast radiation therapy in the prone position: implications for targeting the undissected axilla

PURPOSE

One interpretation of the American College of Surgeons Oncology Group Z0011 trial is that whole breast radiation therapy, known to treat a portion of the low axilla when delivered in the supine position, can treat residual microscopic disease in patients with involved axillary nodes that were not removed by axillary dissection. The purpose of this study was to quantify radiation dose delivered to the axilla for patients treated in the prone position.

METHODS AND MATERIALS

We analyzed treatment plans from 40 consecutive patients who received radiation targeting the intact breast with tangent fields in the prone position. Axillary levels were contoured using Radiation Therapy Oncology Group (RTOG) definitions and radiation dose- volume calculations were made for axillary levels, heart, and lungs. We generated revised plans for 10 patients by modifying the tangent beams to increase axillary dose and compared original with modified plans.

RESULTS

The median proportion of the axilla covered by 90% of the prescription dose was 13% of level I (range, 0%-61%), 0% of level II (range, 0%-6%), and 0% of level III (range, 0%-0%). More of the level I axilla was covered in obese compared with nonobese patients (P = .013). Level I coverage did not differ significantly by laterality (P = .740) or tumor location (P = .527). Modification of the treatment plans significantly increased level I coverage (P = .005) with all modified plans delivering 90% of the prescription dose to at least 96% of the level I axilla. The modified plans had increased lung (P = .005) and heart (P = .028) dose, which were within acceptable RTOG normal tissue constraints.

CONCLUSIONS

Most patients treated with standard whole breast tangential radiation in the prone position receive subtherapeutic dose to the level I and II axilla. Patients treated in the prone position who require therapeutic radiation dose to the low axilla need treatment field modification; this is feasible for many patients using tangent fields.

No difference in dose distribution in organs at risk in postmastectomy radiotherapy with or without breast implant reconstruction

The aim of this study was to quantify the variation in doses to organs at risk (ipsilateral lung and heart) and the clinical target volume (CTV) in the presence of breast implants. In this retrospective cohort study, patients were identified through the National Breast Cancer Register. Consecutive breast cancer patients undergoing mastectomy between 2009 and 2011 and completing a full course of postmastectomy radiotherapy (PMRT) were eligible. All included patients (n = 818) were identified in the ARIA© oncology information system and further stratified for immediate breast reconstruction (IBR+, n = 162) and no immediate breast reconstruction (IBR-, n = 656). Dose statistics for ipsilateral lung, heart and CTV were retrieved from the system. Radiation plans for patients with chest wall (CW) only (n = 242) and CW plus lymph nodes (n = 576) irradiation were studied separately.

The outcome variables were dichotomized as follows: lung, V_20Gy ≤ 30% vs. V_20Gy > 30%; heart, D_mean ≤ 5 Gy vs. D_mean > 5 Gy; CTV, V_95% ≥ median vs. V_95% < median.

In the univariate and multivariate regression models no correlation between potential confounders (i.e. breast reconstruction, side of PMRT, CW index) and the outcome variables was found. Multivariate analysis of CW plus lymph nodes radiation plans, for example, showed no association of breast reconstruction with dosimetric outcomes in neither lung nor heart- lung V_20Gy (odds ratio [OR]: 0.6, 95%CI, 0.4 to 1.0, p = 0.07) or heart D_mean (OR: 1.2, 95%CI, 0.5 to 3.1, p = 0.72), respectively.

CTV was statistically significantly larger in the IBR+ group (i.e. included breast implant), but no correlation between the implant type and dosimetric characteristics of the organs at risk was revealed.

In the current study, the presence of breast implants during postmastectomy radiotherapy was not associated with increased doses to ipsilateral lung and heart, but CTV definition and its dosimetric characteristics urge further evaluation.

Comparison of Different Techniques in Breast Cancer Radiotherapy Planning

OBJECTIVE

This study aimed to minimize the radiation dose to organs other than the target tissue during adjuvant therapy applied for breast cancer, by using different planning methods.

MATERIALS AND METHODS

30 women with T1-2 N1-3 M0 breast cancer were included in the study. Planning was performed using four different methods to the supraclavicular area, internal, and external tangential fields. All planning was done in a virtual environment by and the requested data was obtained. All patients were treated by the 1st method. Method 1: Different isocenter, complete supraclavicular area, breast half beam. Method 2: Different isocenter, half supraclavicular area, breast half beam. Method 3: Single isocenter, half supraclavicular area, breast half beam. Method 4: Different isocenter, supraclavicular area full beam, breast full beam.

RESULTS

Evaluation of PTV values showed a statistically significant reduction in D-max, 110% and 115% values by method III. Lower doses in other parameters were not statistically significant.

CONCLUSION

Based on these results, the application of single isocenter, 3D radiotherapy in breast cancer provides significant advantages especially in PTV and pulmonary dosages.

The feasibility of evaluating radiation dose to the heart by integrating kilovoltage-cone beam computed tomography in stereotactic body radiotherapy of early non-small-cell lung cancer patients

BACKGROUND

To investigate the feasibility of contouring the planning risk organ volume (PRV) for the heart, and to determine the probability of evaluating radiation dose to the heart using kilovoltage-cone beam computed tomography (kV-CBCT) in early-stage non-small-cell lung cancer (NSCLC) patients, who received stereotactic body radiotherapy (SBRT).

MATERIALS AND METHODS

Seventeen NSCLC patients who received SBRT (5Gy/f × 10f dose) were enrolled and subjected to CBCT and CT imaging analyses to plan treatment. Sequential planning CBCT images of individual patient's hearts were analyzed for reproducibility of heart contouring and volume. Comparative analyses were made between the planning CT- and CBCT-detected heart margins and dose-volume indices for treatment.

RESULTS

The heart volume from planning CT images was significantly smaller than that from CBCT scans (p < 0.05), and the volumes based on the different series of CBCT images were similar (p > 0.05).The overlap of the heart region on the same anatomical section between the first series of CBCT scans and other scans reached 0.985 ± 0.020 without statistically significant differences (p > 0.05). The mean margins of the heart from planning CT and CBCT scans were 10.5 ± 2.8 mm in the left direction, 5.9 ± 2.8 mm in the right direction, 2.2 ± 1.6 mm in the direction of the head, 3.3 ± 2.2 mm in the direction of the foot, 6.7 ± 1.1 mm in the anterior direction, and 4.5 mm ± 2.5 mm in the posterior direction. All relative and absolute dose-volume indices obtained from CBCT images were significantly larger than those from planning CT scans (p < 0.05), with the exception of the volume in the 5Gy region.

CONCLUSION

The PRV of heart contouring based on kV-CBCT is feasible with good reproducibility. More accurate and objective dose-volume indices may be obtained for NSCLC patients by using kV-CBCT, instead of CT, to plan SBRT.

Dosimetric and clinical advantages of deep inspiration breath-hold (DIBH) during radiotherapy of breast cancer

BACKGROUND

To investigate the potential dosimetric and clinical benefits of Deep Inspiration Breath-Hold (DIBH) technique during radiotherapy of breast cancer compared with Free Breathing (FB).

METHODS

Eight left-sided breast cancer patients underwent a supervised breath hold during treatment. For each patient, two CT scans were acquired with and without breath hold, and virtual simulation was performed for conventional tangential fields, utilizing 6 or 15 MV photon fields. The resulting dose-volume histograms were calculated, and the volumes of heart/lung irradiated to given doses were assessed. The left anterior descending coronary artery (LAD) mean and maximum doses were calculated, together with tumour control probability (TCP) and normal tissue complication probabilities (NTCP) for lung and heart.

RESULTS

For all patients a reduction of at least 16% in lung mean dose and at least 20% in irradiated pulmonary volumes was observed when DIBH was applied. Heart and LAD maximum doses were decreased by more than 78% with DIBH. The NTCP values for pneumonitis and long term cardiac mortality were also reduced by about 11% with DIBH. The NTCP values for pericarditis were zero for both DIBH and FB.

CONCLUSION

Delivering radiation in DIBH conditions the dose to the surrounding normal structures could be reduced, in particular heart, LAD and lung, due to increased distance between target and heart, and to reduced lung density.

Cardiovascular effects after low-dose exposure and radiotherapy: what research is needed?

The authors of this report met at the Head Quarter of the International Atomic Energy Agency (IAEA) in Vienna, Austria, on 2-4 July 2012, for intensive discussions of an abundance of original publications on new epidemiological studies on cardiovascular effects after low-dose exposure and radiotherapy and radiobiological experiments as well as several comprehensive reviews that were published since the previous meeting by experts sponsored by the IAEA in June 2006. The data necessitated a re-evaluation of the situation with special emphasis on the consequences current experimental and clinical data may have for clinical oncology/radiotherapy and radiobiological research. The authors jointly arrived at the conclusions and recommendations presented here.

Primary cardiac sarcomas: a retrospective study of the French Sarcoma Group

INTRODUCTION

Primary cardiac sarcomas (PCS) are rare tumours of dismal prognosis.

METHODS

Data of 124 patients with PCS referred to institutions of the French Sarcoma Group (FSG) from 1977 and 2010 were reviewed.

RESULTS

Median age was 48.8years. PCS were poorly-differentiated sarcomas (N=45, 36.3%), angiosarcomas (N=40, 32.3%), leiomyosarcomas (N=16, 12.9%) and others (N=23, 18.6%). At diagnosis, 100 patients (80.6%) were localised and 24 (19.4%) metastatic. Tumours were located in the right (N=47, 38.8%), left atrial cavities (N=45, 37.2%) or encompassed several locations in nine cases (7.4%). Surgery was performed in 81 cases (65.3%). Heart transplant was performed in five patients. Radiotherapy adjuvant (N=18, 14.5%) or alone (N=6, 4.8%) was performed in non-metastatic patients only (N=24, 19.4%). With a median follow-up of 51.2months, median overall survival (OS) was 17.2months for the entire cohort, 38.8months after complete resection versus 18.2 after incomplete resection and 11.2months in non-resected patients. Radiotherapy was associated with improved progression-free survival (PFS) on multivariate analysis. Chemotherapy was significantly associated with better OS only in non-operated patients but not in operated patients. In non-metastatic patients, surgery (hazard ratio [HR]=0.42, p<0.001), male gender (HR=0.56, p=.032) was associated with better OS and surgery (HR=0.61; p=.076), radiotherapy (HR=0.43; p=.004) and chemotherapy (HR=0.30, p=.003) improved PFS.

CONCLUSION

Only surgical resection is associated with a perspective of prolonged survival. Chemotherapy is associated with a better outcome in non-resected patients.

Estimation of the displacement of cardiac substructures and the motion of the coronary arteries using electrocardiographic gating

Purpose

The aim of this study was to quantify the displacement of cardiac substructures, including the anterior myocardial territory (AMT), left ventricle, and coronary arteries during a normal cardiac cycle.

Materials and methods

Computed tomography (CT) images with retrospective electrocardiographic gating of 17 eligible patients were obtained. All images were reconstructed automatically for the end-diastolic and end-systolic phases. CT scanning without contrast at a random phase and a selected vertebral body were used as references to measure three-dimensionaldisplacements of the cardiac substructures.

Results

The displacement between the end-diastolic and end-systolic phases (D_d-s) was greater than that between the end-systolic and random phases and between the end-diastolic and random cardiac phases. The largest displacements for the heart were in the left, posterior, and inferior directions with an average D_d-s of approximately 4–6 mm. The average D_d-s for the AMT and left ventricle was 1.2–2.7 mm in the anterior and right directions, 4.3–7.8 mm in left and posterior directions, and 4.9–6.3 mm in superior and inferior directions. For the coronary arteries, the average D_d-s was 2.8–5.9 mm in the anterior-posterior direction, 3.5–6.6 mm in left-right direction, and 3.8–5.3 mm in the superior-inferior direction. Inter-observer agreement was excellent for the heart, AMT, and left ventricle (kappa coefficient, >0.75 for all) and good for most coronary arteries in three dimensions (kappa coefficient, 0.511–0.687). The D_d-s did not differ significantly between men and women.

Conclusion

Most average displacements of the cardiac substructures and coronary arteries were 3–8 mm in three dimensions. These findings will be useful to accurately estimate the radiation dose to cardiac substructures during thoracic radiation and to evaluate the risk of radiation-related heart disease.

Internal mammary node management in breast cancer. A review

BACKGROUND

Internal mammary nodes visualized during sentinel node biopsy for breast cancer, remain an unresolved management issue. Further, both internal mammary node (IMN) radiotherapy and biopsy have attendant risks and hence should be used with caution. The purpose of this review is to highlight the available data and evidence.

METHODS AND RESULTS

A PubMed database from 1960 to 2012 using key words: internal mammary nodes, breast cancer radiotherapy planning, adjuvant radiotherapy, sentinel node biopsy in breast cancer and selected publications on the significance of internal mammary nodes in breast cancer treatment, published data and approaches used. We found 14513 relevant papers and we selected 30 that clearly investigated the management of internal mammary nodes during sentinel node search. We focused on the incidence of IMN metastasis (6 papers), risk factors associated with IMN drainage (9 reports), management of IMN and the impact on disease free and overall patient survival (15 papers).

CONCLUSIONS

The evidence for breast cancer axillary nodes management is good but the data for other draining nodes such as internal mammary nodes are far less conclusive and further research is needed.

Helical tomotherapy for inoperable breast cancer: a new promising tool

BACKGROUND

We investigated the feasibility of helical tomotherapy (HT) for inoperable large breast tumors, after failing to achieve adequate treatment planning with conformal radiation techniques.

MATERIAL AND METHODS

Five consecutive patients with locally advanced breast cancer (LABC) were treated by preoperative HT. All patients received up-front chemotherapy before HT. Irradiated volumes included breast and nodal areas (45-50 Gy) in 4 patients. One patient received a simultaneous integrated boost (55 Gy) to gross tumor volume (GTV) without lymph node irradiation. Acute toxicity was assessed with Common Toxicity Criteria for Adverse Events v.4. Patients were evaluated for surgery at the end of treatment.

RESULTS

Patients were staged IIB to IIIC (according to the AJCC staging system 2010). HT was associated in 4 patients with concomitant chemotherapy (5-fluorouracil and vinorelbine). Two patients were scored with grade 3 skin toxicity (had not completed HT) and one with grade 3 febrile neutropenia. One patient stopped HT with grade 2 skin toxicity. All patients were able to undergo mastectomy at a median interval of 43 days (31-52) from HT. Pathological partial response was seen in all patients.

CONCLUSIONS

HT is feasible with acceptable toxicity profiles, potentially increased by chemotherapy. These preliminary results prompt us to consider a phase II study.