Heart-sparing radiotherapy techniques in breast cancer patients: a recommendation of the breast cancer expert panel of the German society of radiation oncology (DEGRO)

Is intensive training with a time interval between instruction and planning CT necessary for deep inspiration breath-hold radiotherapy in breast cancer?

BACKGROUND

Breathing instruction and exercises and a time gap between training and planning CT scans (pCT) is recommended as part of deep inspiration breath-hold (DIBH) assisted radiotherapy (RT). However, this is associated with additional time expenditure.

MATERIALS AND METHODS

In two of the authors' treatment centers (TC), patient training took place before the planning CT of DIBH-assisted therapy. In TC 1, a further appointment was made with a minimum interval of 2 days to perform the planning CT. At TC 2, the planning CT was performed immediately after the first patient instruction. A retrospective evaluation of the clinical parameters of the therapy was carried out to investigate the relevance of the time gap between DIBH exercises and pCT.

RESULTS

A total of 72 patients were included, 35 of whom were treated in TC 1 and 37 in TC 2. In TC 1, an average interval of ~4 days was observed between patient training and planning CT, while in TC 2, training and CT were performed immediately after each other. No significant differences in radiation dose exposure of the lung on the treated side, the whole lung, or the heart were found between the two centers. Furthermore, there was no significant difference in the application of the daily RT fraction. The requirement for daily positioning checks was also the same at both treatment centers.

CONCLUSION

This study does not show any advantages for a time gap between instruction/training and pCT. Skipping the time break does not deteriorate any clinically relevant endpoints.

Incidental dose distribution to contralateral internal mammary nodes in breast cancer patients undergoing adjuvant radiotherapy

Background and purpose

In a relevant number of primary breast cancer patients, lymphatic drainage to the contralateral internal mammary nodes (cIMN) is being observed. Nevertheless, so far lymphatic drainage pathway to the cIMN is largely neglected during adjuvant radiotherapy.

Materials and methods

This study evaluated the incidental dose to the cIMN for 120 volumetric modulated arc therapy (VMAT) treatment plans for node positive breast in dependence of internal mammary node irradiation (IMNI) and deep inspiration breath hold (DIBH). Additionally, incidental dose distribution to the cIMN based on the field design in the MA20, EORTC22922/10925 and AMAROS trials was assessed.

Results

The incidental dose (Dmean ± SD) to the cIMN-CTV was 13.0 (±4.7) Gy with a maximum dose of < 30 Gy in 113/120 cases. If IMNI was included (n = 80), the Dmean to the cIMN-CTV was significantly higher compared to no IMNI, but still comparably low (n = 40; 14.3 Gy vs. 9.6 Gy; p = 0.0001). Furthermore, the dose in the cIMN during free breathing (n = 80) was higher compared to DIBH (n = 40; 13.9 Gy vs. 11.2 Gy; p = 0.002).Simulated treatment plans based on the randomized RNI trials revealed neglectable dose coverage of the cIMN (Dmean 1.0-1.8 Gy) for all protocols.

Conclusion

Neither in the randomized RNI trials nor during contemporary treatment techniques clinically relevant dose distribution to the cIMN was observed. Further studies are warranted to assess the potential impact of intended irradiation of cIMN in high-risk patients.

Deep Inspiration Breath Hold in Left-Sided Breast Radiotherapy: A Balance Between Side Effects and Costs

Background

Deep inspiration breath hold (DIBH) is an effective technique for reducing heart exposure during radiotherapy for left-sided breast cancer. Despite its benefits, cost considerations and its impact on workflow remain significant barriers to widespread adoption.

Objectives

This study aimed to assess the cost-effectiveness of DIBH and compare its operational, financial, and clinical outcomes with free breathing (FB) in breast cancer treatment.

Methods

Treatment plans for 100 patients with left-sided breast cancer were generated using both DIBH and FB techniques. Dosimetric data, including the average mean heart dose, were calculated for each technique and used to estimate the cardiotoxicity of radiotherapy. A state-transition microsimulation model based on SCORE2 (Systematic Coronary Risk Evaluation) algorithms projected the effects of DIBH on cardiovascular outcomes and quality-adjusted life-years (QALYs). Costs were calculated from a provider perspective using time-driven activity-based costing, applying a willingness-to-pay threshold of €40,000 for cost-effectiveness assessment. A discrete event simulation model assessed the impacts of DIBH vs FB on throughput and waiting times in the radiotherapy workflow.

Results

In the base case scenario, DIBH was associated with an absolute risk reduction of 1.72% (95% CI: 1.67%-1.76%) in total cardiovascular events and 0.69% (95% CI: 0.67%-0.72%) in fatal cardiovascular events over 20 years. Additionally, DIBH was estimated to provide an incremental 0.04 QALYs (95% CI: 0.05-0.05) per left-sided breast cancer patient over the same time period. However, DIBH increased treatment times, reducing maximum achievable throughput by 12.48% (95% CI: 12.36%-12.75%) and increasing costs by €617 per left-sided breast cancer patient (95% CI: €615-€619). The incremental cost-effectiveness ratio was €14,023 per QALY.

Conclusions

Despite time investments, DIBH is cost-effective in the Belgian population. The growing adoption of DIBH may benefit long-term cardiovascular health in breast cancer survivors.

Cardiac doses with deep inspiration breath hold in breast cancer radiotherapy: direct comparison between WBI, PBI, and interstitial APBI

Background

The optimal radiotherapy technique for cardiac sparing in left-sided early breast cancer (EBC) is not clear. In this context, the aim of our dosimetric study was to compare cardiac and lung doses according to the type of radiotherapy - whole breast irradiation (WBI), external partial breast irradiation (PBI), and multicatheter interstitial brachytherapy-accelerated partial breast irradiation (MIB-APBI). The dosimetric results with the WBI and PBI were calculated with and without DIBH.

Materials and methods

Dosimetric study of 23 patients treated with WBI, PBI, with and without DIBH, or MIB-APBI. The prescribed dose was 40 Gy in 15 fractions for WBI and PBI and 34 Gy in 10 fractions (bid) for MIB-APBI. Doses to the organs-at-risk (OAR) - heart, left anterior descending coronary artery (LAD), left ventricle (LV), and left lung - were recalculated to the equivalent dose in 2-Gy fractions (EQD2).

Results

The addition of DIBH significantly reduced EQD2 doses to all OARs (except for the left lung maximal dose) in WBI and PBI. MHD values were 0.72 Gy for DIBH-WBI, 1.01 Gy for MIB-APBI and 0.24 Gy for DIBH-PBI. There were no significant differences in cardiac doses between WBI with DIBH and PBI without DIBH. DIBH-PBI resulted in significantly lower mean doses to all OARs (except for maximum lung dose) compared to MIB-APBI. Conclusions: These results show that the use of DIBH significantly reduces cardiac doses in patients with left EBC. Partial irradiation techniques (PBI, MIB-APBI) significantly reduced cardiac doses due to the smaller clinical target volume. The best results were obtained with DIBH-PBI.

Surface-guided radiotherapy systems in locoregional deep inspiration breath hold radiotherapy for breast cancer - a multicenter study on the setup accuracy

Background

Daily image-guided radiotherapy (IGRT) and deep inspiration breath hold (DIBH) technique are recommended for locoregional RT of breast cancer. The optimal workflow for a combination of surface-guided RT (SGRT) with DIBH technique is of current clinical interest.

Materials and methods

The setup accuracy at three hospitals was evaluated using different SGRT workflows. A total of 150 patients (2269 image pairs) were analyzed in three groups: patient setup with the AlignRT® SGRT system in Tampere (Site 1, n = 50), the Catalyst™ SGRT system in Turku (Site 2, n = 50) and the Catalyst™ SGRT system in Jönköping (Site 3, n = 50). Each site used their routine workflow with SGRT-based setup and IGRT positioning. Residual errors of the bony chest wall, thoracic vertebra (Th 1) and humeral head were evaluated using IGRT images.

Results

Systematic residual errors in the cranio-caudal (CC) direction and in pitch were generally larger at Site 2 than those at Sites 1 and 3 (p = 0.01-0.7). With daily IGRT, only a small difference (p = 0.01-0.9) was observed in residual random errors of bony structures in other directions between sites.

Conclusion

The introduction of SGRT and the use of daily IGRT lead to small residual errors when combining the best workflow practices from different hospitals. Our multicenter evaluation led to improved workflow by tightening the SGRT tolerances on Site 2 and fixation modification. Because of mainly small random errors, systematic posture errors in the images need to be corrected after posture correction with new setup surfaces. We recommend tight SGRT tolerances, good fixation and correction of systematic errors.

Unveiling innovative therapeutic strategies and future trajectories on stimuli-responsive drug delivery systems for targeted treatment of breast carcinoma

This comprehensive review delineates the latest advancements in stimuli-responsive drug delivery systems engineered for the targeted treatment of breast carcinoma. The manuscript commences by introducing mammary carcinoma and the current therapeutic methodologies, underscoring the urgency for innovative therapeutic strategies. Subsequently, it elucidates the logic behind the employment of stimuli-responsive drug delivery systems, which promise targeted drug administration and the minimization of adverse reactions. The review proffers an in-depth analysis of diverse types of stimuli-responsive systems, including thermoresponsive, pH-responsive, and enzyme-responsive nanocarriers. The paramount importance of material choice, biocompatibility, and drug loading strategies in the design of these systems is accentuated. The review explores characterization methodologies for stimuli-responsive nanocarriers and probes preclinical evaluations of their efficacy, toxicity, pharmacokinetics, and biodistribution in mammary carcinoma models. Clinical applications of stimuli-responsive systems, ongoing clinical trials, the potential of combination therapies, and the utility of multifunctional nanocarriers for the co-delivery of assorted drugs and therapies are also discussed. The manuscript addresses the persistent challenge of drug resistance in mammary carcinoma and the potential of stimuli-responsive systems in surmounting it. Regulatory and safety considerations, including FDA guidelines and biocompatibility assessments, are outlined. The review concludes by spotlighting future trajectories and emergent technologies in stimuli-responsive drug delivery, focusing on pioneering approaches, advancements in nanotechnology, and personalized medicine considerations. This review aims to serve as a valuable compendium for researchers and clinicians interested in the development of efficacious and safe stimuli-responsive drug delivery systems for the treatment of breast carcinoma.

Organ-sparing techniques and dose-volume constrains used in breast cancer radiation therapy - Results from European and Latin American surveys

Background

Advances in local and systemic therapies have improved the outcomes of patients with breast cancer (BC), leading to a possible increased risk for postoperative radiation therapy (RT) late adverse events. The most adequate technologies and dose constraints for organs at risk (OAR) in BC RT have yet to be defined.

Methods

An online survey was distributed to radiation oncologists (ROs) practicing in Europe and Latin America including the Caribbean (LAC) through personal contacts, RO and BC professional groups' networks. Demographic data and clinical practice information were collected.

Results

 The study included 585 responses from ROs practicing in 57 different countries. The most frequently contoured OAR by European and LAC participants were the whole heart (96.6 % and 97.7 %), the ipsilateral (84.3 % and 90.8 %), and contralateral lung (71.3 % and 77.4 %), whole lung (69.8 % and 72.9 %), and the contralateral breast (66.4 % and. 83.2 %). ESTRO guidelines were preferred in Europe (33.3 %) and the RTOG contouring guideline was the most popular in LAC (62.2 %), while some participants used both recommendations (13.2 % and 19.2 %). IMRT (68.6 % and 59.1 %) and VMAT (65.6 % and 60.2 %) were the preferred modalities used in heart sparing strategies, followed by deep inspiration breath-hold (DIBH) (54.8 % and 37.4 %) and partial breast irradiation (PBI) (41.6 % and 24.6 %). Only a small percentage of all ROs reported the dose-volume constraints for OAR used in routine clinical practice. A mean heart dose (Heart-Dmean) between 4 and 5 Gy was the most frequently reported parameter (17.2 % and 39.3 %).

Conclusion

 The delineation approaches and sparing techniques for OAR in BC RT vary between ROs worldwide. The low response rate to the dose constraints subset of queries reflects the uncertainty surrounding this topic and supports the need for detailed consensus recommendations in the clinical practice.

Cardiac structure, function, and coronary anatomy 10 years after isolated contemporary adjuvant radiotherapy in breast cancer patients with low cardiovascular baseline risk

AIMS

The effects of isolated contemporary low-dose breast cancer (BC) radiotherapy (RT) on the heart remain poorly understood. This study aims to assess the long-term impacts of BC-RT on cardiac structure and function.

METHODS AND RESULTS

Seventy-six women (62 ± 7 years) without history of prior heart disease, who had undergone RT for either first left (n = 36) or right (n = 40) BC, without additional medical oncology therapy apart from hormonal treatment 11 ± 1 years earlier, underwent transthoracic echocardiography, cardiac magnetic resonance imaging (CMR), computed tomography coronary angiography (CTCA), NT-proBNP, and a 6-min walk test (6MWT). They were compared with 54 age-matched healthy female controls. By CTCA, 68% of BC patients exhibited no or very mild coronary disease, while only 11% had moderate stenosis (50-69%) and 3% had significant stenosis (>70%). Despite slightly reduced regional echocardiographic midventricular strains, BC patients exhibited similar global left and right ventricular volumes, ejection fractions, and global strains by echocardiography and CMR as controls. Mitral E/e' ratios were slightly higher, and mitral deceleration times were slightly lower, but NT-proBNP was similar to controls. Also, 6MWT was normal. None had late gadolinium enhancement, and extracellular volume fraction was similar in BC (28 ± 3 vs. 29 ± 3, P = 0.15) and controls. No differences were observed relative to dose or side of RT.

CONCLUSION

Aside from minor alterations of regional strains and diastolic parameters, women who received isolated RT for BC had low prevalence of coronary disease, normal global systolic function, NT-proBNP, and exercise capacity and showed no structural changes by CMR, refuting significant long-term cardiotoxicity in such low-risk patients.

Exploring Helium Ions' Potential for Post-Mastectomy Left-Sided Breast Cancer Radiotherapy

Proton therapy presents a promising modality for treating left-sided breast cancer due to its unique dose distribution. Helium ions provide increased conformality thanks to a reduced lateral scattering. Consequently, the potential clinical benefit of both techniques was explored. An explorative treatment planning study involving ten patients, previously treated with VMAT (Volumetric Modulated Arc Therapy) for 50 Gy in 25 fractions for locally advanced, node-positive breast cancer, was carried out using proton pencil beam therapy with a fixed relative biological effectiveness (RBE) of 1.1 and helium therapy with a variable RBE described by the mMKM (modified microdosimetric kinetic model). Results indicated that target coverage was improved with particle therapy for both the clinical target volume and especially the internal mammary lymph nodes compared to VMAT. Median dose value analysis revealed that proton and helium plans provided lower dose on the left anterior descending artery (LAD), heart, lungs and right breast than VMAT. Notably, helium therapy exhibited improved ipsilateral lung sparing over protons. Employing NTCP models as available in the literature, helium therapy showed a lower probability of grade ≤ 2 radiation pneumonitis (22% for photons, 5% for protons and 2% for helium ions), while both proton and helium ions reduce the probability of major coronary events with respect to VMAT.

Robustness analysis of surface-guided DIBH left breast radiotherapy: personalized dosimetric effect of real intrafractional motion within the beam gating thresholds

PURPOSE

The robustness of surface-guided (SG) deep-inspiration breath-hold (DIBH) radiotherapy (RT) for left breast cancer was evaluated by investigating any potential dosimetric effects due to the residual intrafractional motion allowed by the selected beam gating thresholds. The potential reduction of DIBH benefits in terms of organs at risk (OARs) sparing and target coverage was evaluated for conformational (3DCRT) and intensity-modulated radiation therapy (IMRT) techniques.

METHODS

A total of 192 fractions of SGRT DIBH left breast 3DCRT treatment for 12 patients were analyzed. For each fraction, the average of the real-time displacement between the isocenter on the daily reference surface and on the live surface ("SGRT shift") during beam-on was evaluated and applied to the original plan isocenter. The dose distribution for the treatment beams with the new isocenter point was then calculated and the total plan dose distribution was obtained by summing the estimated perturbed dose for each fraction. Then, for each patient, the original plan and the perturbed one were compared by means of Wilcoxon test for target coverage and OAR dose-volume histogram (DVH) metrics. A global plan quality score was calculated to assess the overall plan robustness against intrafractional motion of both 3DCRT and IMRT techniques.

RESULTS

Target coverage and OAR DVH metrics did not show significant variations between the original and the perturbed plan for the IMRT techniques. 3DCRT plans showed significant variations for the left descending coronary artery (LAD) and the humerus only. However, none of the dose metrics exceeded the mandatory dose constraints for any of the analyzed plans. The global plan quality analysis indicated that both 3DCRT and IMRT techniques were affected by the isocenter shifts in the same way and, generally, the residual isocenter shifts more likely tend to worsen the plan in all cases.

CONCLUSION

The DIBH technique proved to be robust against residual intrafractional isocenter shifts allowed by the selected SGRT beam-hold thresholds. Small-volume OARs located near high dose gradients showed significant marginal deteriorations in the perturbed plans with the 3DCRT technique only. Global plan quality was mainly influenced by patient anatomy and treatment beam geometry rather than the technique adopted.

Breast Volume Is a Predictor of Higher Heart Dose in Whole-Breast Supine Free-Breathing Volumetric-Modulated Arc Therapy Planning

In breast cancer volumetric-modulated arc therapy (VMAT) planning, the rotation of the gantry around the target implies a greater dose spreading to the whole heart, compared to tangential-field standard treatment. A consecutive cohort of 121 breast cancer patients treated with the VMAT technique was investigated. The correlation of breast volume, heart volume and lung volume with mean heart dose (mHD) and mean and maximum LAD dose (mLAD dose, MLAD dose) was tested, and a subsequent a linear regression analysis was carried out. VMAT treatment plans from 56 left breast cancer and 65 right breast cancer patients were analyzed. For right-sided patients, breast volume was significantly correlated with mHD, mLAD and MLAD dose, while for left-sided patients, breast volume was significantly correlated with mHD and mLAD, while heart volume and lung volume were correlated with mHD, mLAD and MLAD dose. Breast volume was the only predictor of increased heart and LAD dose (p ≤ 0.001) for right-sided patients. In left-sided patients, heart and lung were also predictors of increased mHD (p = 0.005, p ≤ 0.001) and mean LAD dose (p = 0.009, p ≤ 0.001). In this study, we observed an increase in heart and LAD doses in larger-breasted patients treated with VMAT planning. In right-sided patients, breast volume was shown to be the only predictor of increased heart dose and LAD dose.

Association of radiation dose to cardiac substructures with major ischaemic events following breast cancer radiotherapy

BACKGROUND AND AIMS

Patients with left-sided breast cancer receive a higher mean heart dose (MHD) after radiotherapy, with subsequent risk of ischaemic heart disease. However, the optimum dosimetric predictor among cardiac substructures has not yet been determined.

METHODS AND RESULTS

This study retrospectively reviewed 2158 women with breast cancer receiving adjuvant radiotherapy. The primary endpoint was a major ischaemic event. The dose-volume parameters of each delineated cardiac substructure were calculated. The risk factors for major ischaemic events and the association between MHD and major ischaemic events were analysed by Cox regression. The optimum dose-volume predictors among cardiac substructures were explored in multivariable models by comparing performance metrics of each model. At a median follow-up of 7.9 years (interquartile range 5.6-10.8 years), 89 patients developed major ischaemic events. The cumulative incidence rate of major ischaemic events was significantly higher in left-sided disease (P = 0.044). Overall, MHD increased the risk of major ischaemic events by 6.2% per Gy (hazard ratio 1.062, 95% confidence interval 1.01-1.12; P = 0.012). The model containing the volume of the left ventricle receiving 25 Gy (LV V25) with the cut-point of 4% presented with the best goodness of fit and discrimination performance in left-sided breast cancer. Age, chronic kidney disease, and hyperlipidaemia were also significant risk factors.

CONCLUSION

Risk of major ischaemic events exist in the era of modern radiotherapy. LV V25 ≥ 4% appeared to be the optimum parameter and was superior to MHD in predicting major ischaemic events. This dose constraint could aid in achieving better heart protection in breast cancer radiotherapy, though a further validation study is warranted.

Preventing Cardiotoxicity in Personalized Breast Irradiation

BACKGROUND

This study aims to assess the benefit of a deep inspiration breath hold (DIBH) over the standard irradiation technique, and eventually to identify anatomical and/or treatment preplanning characteristics correlated with the LAD dose.

METHODS

Patients with left-sided breast cancer undergoing whole breast radiotherapy with DIBH were analyzed. All patients included in the analysis had plans in DIBH and free-breathing (FB). Receiving operating characteristics (ROC analysis) were used to identify the cut-off point of parameters to predict the LAD maximum dose > 10 Gy and LAD mean dose > 4 Gy, and the areas under the curve (AUCs) were computed. Post-test probability has been performed to evaluate the effect of parameters' combination.

RESULTS

One hundred ninety-seven patients were analyzed. The LAD dose was significantly reduced in DIBH plans with the maximum and mean dose reduced by 31.7% (mean value 3.5 Gy vs. 4.8 Gy, p ≤ 0.001) and 28.1% (mean value 8.2 Gy vs. 12.8 Gy, p ≤ 0.001) in DIBH plans compared to FB plans. The strongest predictor of the LAD dose (maximum > 10 Gy and mean > 4 Gy) was the minimum distance of LAD from tangent open fields. Other parameters were lung volume and heart volume (LAD Dmax > 10 Gy) and lung volume, heart volume, and breast separation (LAD Dmean > 4 Gy).

CONCLUSION

The dosimetric advantage of DIBH is clear in all patients and DIBH should always be preferred.

Estimating follow-up CTs from geometric deformations of catheter implants in interstitial breast brachytherapy: A feasibility study using electromagnetic tracking

BACKGROUND

Electromagnetic tracking (EMT) systems have been shown to provide valuable information on the geometry of catheter implants in breast cancer patients undergoing interstitial brachytherapy (iBT). In the context of an extended patient-specific, pre-treatment verification, EMT can play a key role in determining the potential need and, if applicable, the appropriate time for treatment adaptation. To detect dosimetric shortcomings the relative position between catheters, and target volume and critical structures must be known. Since EMT cannot provide the anatomical context and standard imaging techniques such as cone-beam CT are not yet available in most brachytherapy suites, it is not possible to detect anatomic changes on a daily or fraction basis, so the need for adaptive planning cannot be identified.

PURPOSE

The aim of this feasibility study is to develop and evaluate a technique capable of estimating follow-up CTs at any time based on the initial treatment planning CT (PCT) and surrogate information about changes of the implant geometry from an EMT system.

METHODS

A deformation vector field is calculated from two different implant reconstructions acquired in treatment position through EMT, the first immediately after the PCT and the second at another time point during the course of treatment. The calculation is based on discrete displacement vectors of pairs of control and target points. These are extrapolated by means of different radial basis functions in order to cover the entire CT volume. The adequate parameters for the calculation of the deformation field were identified. By warping the PCT according to the deformation field, one obtains an estimated CT (ECT) that reflects the geometric changes. For the proof of concept, ECTs were computed for the time point of the clinical follow-up CT (FCT) that is embedded in the treatment workflow after the fourth fraction.

RESULTS

ECT and clinical FCTs of 20 patients were compared to each other quantitatively in terms of absolute Hounsfield unit differences in the planning target volume (PTV) and in a convex hull (CH) enclosing the catheters. The median differences were 31.2  and 29.5 HU for the CH and the PTV, respectively.

CONCLUSION

The proposed ECT approach was able to approximate the "anatomy of the day" and therefore, in principle, allows a dosimetric appraisal of the treatment plan quality before each fraction. In this way, it can contribute to a more detailed patient-specific quality assurance in iBT of the breast and help to identify the timing for a potential treatment adaptation.

Regional nodal irradiation in breast cancer patients: Effects of deep inspiration breath hold on the internal mammary chain location

The purpose of this study was to investigate the impact of deep inspiration breath hold (DIBH) on the positioning of thoracic structures and provide treatment planning recommendations for internal mammary chain (IMC) irradiation in breast cancer patients. Thirty-two breast cancer patients from our database underwent both DIBH and free breathing (FB) treatment planning. Contouring of the axillary lymph node clinical target volumes (CTVs: level I, II, III, IV, and IMC according to ESTRO), the internal mammary artery (IMA), the heart, and the left anterior descending artery (LAD) was performed. The following were then analyzed: the distance between the IMA and the heart, the craniocaudal distance in which IMC-CTV and heart coexist, the craniocaudal distance between the lower end of the of level III and IV and the upper end of the heart. Several significant geometric differences were observed between DIBH and FB that explain the efficacy of the DIBH for regional nodal irradiation. In >80% of patients the cranial origin of the LAD lies below the lower edge of the IMC-CTV in DIBH. In addition the slices in which the heart/LAD and IMC-CTV coexist decrease during DIBH. The IMA-heart distance is significantly larger in DIBH. Also the craniocaudal distance between the lower border of the CTV level III and IV and the upper border of the heart is larger in DIBH. The observed mechanisms during DIBH contribute significantly to the dose reduction in regional nodal irradiation. To further enhance the benefits of DIBH for the irradiation of the IMC-CTV, it is recommended to implement steep dose gradients in the caudal plane.

Innate Immune System in the Context of Radiation Therapy for Cancer

Radiation therapy (RT) remains an integral component of modern oncology care, with most cancer patients receiving radiation as a part of their treatment plan. The main goal of ionizing RT is to control the local tumor burden by inducing DNA damage and apoptosis within the tumor cells. The advancement in RT, including intensity-modulated RT (IMRT), stereotactic body RT (SBRT), image-guided RT, and proton therapy, have increased the efficacy of RT, equipping clinicians with techniques to ensure precise and safe administration of radiation doses to tumor cells. In this review, we present the technological advancement in various types of RT methods and highlight their clinical utility and associated limitations. This review provides insights into how RT modulates innate immune signaling and the key players involved in modulating innate immune responses, which have not been well documented earlier. Apoptosis of cancer cells following RT triggers immune systems that contribute to the eradication of tumors through innate and adoptive immunity. The innate immune system consists of various cell types, including macrophages, dendritic cells, and natural killer cells, which serve as key mediators of innate immunity in response to RT. This review will concentrate on the significance of the innate myeloid and lymphoid lineages in anti-tumorigenic processes triggered by RT. Furthermore, we will explore essential strategies to enhance RT efficacy. This review can serve as a platform for researchers to comprehend the clinical application and limitations of various RT methods and provides insights into how RT modulates innate immune signaling.

Accelerated Atherosclerosis and Cardiovascular Toxicity Induced by Radiotherapy in Breast Cancer

The number of patients diagnosed with breast cancer and cardiovascular disease is continuously rising. Treatment options for breast cancer have greatly evolved, but radiotherapy (RT) still has a key role in it. Despite many advances in RT techniques, cardiotoxicity is one of the most important side effects. The new cardio-oncology guidelines recommend a baseline evaluation, risk stratification and follow-up of these patients. Cardiotoxicity induced by RT can be represented by almost all forms of cardiovascular disease, with atherosclerosis being the most frequent. An interdisciplinary team should manage these patients, in order to have maximum therapeutic effect and minimum cardiovascular toxicity. This review will summarize the current incidence, risk factors, mechanisms and follow-up of RT-induced cardiovascular toxicity.

Evaluation of Cardiac Substructures Exposure of DIBH-3DCRT, FB-HT, and FB-3DCRT in Hypofractionated Radiotherapy for Left-Sided Breast Cancer after Breast-Conserving Surgery: An In Silico Planning Study

Left-sided breast cancer radiotherapy can lead to late cardiovascular complications, including ischemic events. To mitigate these risks, cardiac-sparing techniques such as deep-inspiration breath-hold (DIBH) and intensity-modulated radiotherapy (IMRT) have been developed. However, recent studies have shown that mean heart dose is not a sufficient dosimetric parameter for assessing cardiac exposure. In this study, we aimed to compare the radiation exposure to cardiac substructures for ten patients who underwent hypofractionated radiotherapy using DIBH three-dimensional conformal radiation therapy (3DCRT), free-breathing (FB)-3DCRT, and FB helical tomotherapy (HT). Dosimetric parameters of cardiac substructures were analyzed, and the results were statistically compared using the Wilcoxon signed-rank test. This study found a significant reduction in the dose to the heart, left anterior descending coronary artery, and ventricles with DIBH-3DCRT and FB-HT compared to FB-3DCRT. While DIBH-3DCRT was very effective in sparing the heart, in some cases, it provided little or no cardiac sparing. FB-HT can be an interesting treatment modality to reduce the dose to major coronary vessels and ventricles and may be of interest for patients with cardiovascular risks who do not benefit from or cannot perform DIBH. These findings highlight the importance of cardiac-sparing techniques for precise delivery of radiation therapy.

Deep inspiration breath-hold radiation therapy in left-sided breast cancer patients: a single-institution retrospective dosimetric analysis of organs at risk doses

BACKGROUND

Radiotherapy can induce cardiac injury in left-sided breast cancer cases. Cardiac-sparing irradiation using the deep inspiration breath-hold (DIBH) technique can achieve substantial dose reduction to vulnerable cardiac substructures compared with free breathing (FB). This study evaluated the dosimetric differences between both techniques at a single institution.

METHODS

From 2017 to 2019, 130 patients with left-sided breast cancer underwent breast-conserving surgery (BCS; n = 121, 93.1%) or mastectomy (ME; n = 9, 6.9%) along with axillary lymph node staging (n = 105, 80.8%), followed by adjuvant irradiation in DIBH technique; adjuvant systemic therapy was included if applicable. 106 (81.5%) patients received conventional and 24 (18.5%) hypofractionated irradiation. Additionally, 12 patients received regional nodal irradiation. Computed tomography (CT) scans in FB and DIBH position were performed for all patients. Intrafractional 3D position monitoring of the patient surface in deep inspiration and breath gating was performed using Sentinel and Catalyst HD 3D surface scanning systems (C-RAD, Catalyst, C‑RAD AB, Uppsala, Sweden). Individual coaching and determination of breathing amplitude during the radiation planning CT was performed. Three-dimensional treatment planning was performed using standard tangential treatment portals (6 or 18 MV). The delineation of cardiac structures and both lungs was done in both the FB and the DIBH scan.

RESULTS

All dosimetric parameters for cardiac structures were significantly reduced (p < 0.01 for all). The mean heart dose (Dmean) in the DIBH group was 1.3 Gy (range 0.5-3.6) vs. 2.2 Gy (range 0.9-8.8) in the FB group (p < 0.001). The Dmean for the left ventricle (LV) in DIBH was 1.5 Gy (range 0.6-4.5), as compared to 2.8 Gy (1.1-9.5) with FB (p < 0.001). The parameters for LV (V10 Gy, V15 Gy, V20 Gy, V23 Gy, V25 Gy, V30 Gy) were reduced by about 100% (p < 0.001). The LAD Dmean in the DIBH group was 4.1 Gy (range 1.2-33.3) and 14.3 Gy (range 2.4-37.5) in the FB group (p < 0.001). The median values for LAD such as V15 Gy, V20 Gy, V25 Gy, V30 Gy, and V40 Gy decreased by roughly 100% (p < 0.001). An increasing volume of left lung in the DIBH position resulted in dose sparing of cardiac structures.

CONCLUSION

For all ascertained dosimetric parameters, a significant dose reduction could be achieved in DIBH technique.

Low doses to the heart in daily practice for treating left-sided breast cancer using accelerated partial-breast irradiation by multicatheter brachytherapy and deep-inspiration breath-hold using a SIB

PURPOSE

The aim of this study was to analyze the heart dose for left-sided breast cancer that can be achieved during daily practice in patients treated with multicatheter brachytherapy (MCBT) accelerated partial-breast irradiation (APBI) and deep-inspiration breath-hold (DIBH) whole-breast irradiation (WBI) using a simultaneous integrated tumor bed boost (SIB)-two different concepts which nonetheless share some patient overlap.

MATERIALS AND METHODS

We analyzed the nominal average dose (Dmean) to the heart as well as the biologically effective dose (BED) and the equivalent dose in 2‑Gy fractions (EQD2) for an α/β of 3 in 30 MCBT-APBI patients and 22 patients treated with DIBH plus SIB. For further dosimetric comparison, we contoured the breast planning target volume (PTV) in each of the brachytherapy planning CTs according to the ESTRO guidelines and computed tangential field plans. Mean dose (Dmean), EQD2 Dmean, and BED Dmean for three dosing schemes were calculated: 50 Gy/25 fractions and two hypofractionated regimens, i.e., 40.05 Gy/15 fractions and 26 Gy/5 fractions. Furthermore, we calculated tangential field plans without a boost for the 22 cases treated with SIB with the standard dosing scheme of 40.05 Gy/15 fractions.

RESULTS

MCBT and DIBH radiation therapy both show low-dose exposure of the heart. As expected, hypofractionation leads to sparing of the heart dose. Although MCBT plans were not optimized regarding dose to the heart, Dmean differed significantly between MCBT and DIBH (1.28 Gy vs. 1.91 Gy, p < 0.001) in favor of MCBT, even if the Dmean in each group was very low. In MCBT radiation, the PTV-heart distance is significantly associated with the dose to the heart (p < 0.001), but it is not in DIBH radiotherapy using SIB.

CONCLUSION

In daily practice, both DIBH radiation therapy as well as MCBT show a very low heart exposure and may thus reduce long term cardiac morbidity as compared to currently available long-term clinical data of patients treated with conventional tangential field plans in free breathing. Our analysis confirms particularly good cardiac sparing with MCBT-APBI, so that this technique should be offered to patients with left-sided breast cancer if the tumor-associated eligibility criteria are fulfilled.

Accuracy of a time-of-flight (ToF) imaging system for monitoring deep-inspiration breath-hold radiotherapy (DIBH-RT) for left breast cancer patients

Deep inspiration breath-hold radiotherapy (DIBH-RT) reduces cardiac dose by over 50%. However, poor breath-hold reproducibility could result in target miss which compromises the treatment success. This study aimed to benchmark the accuracy of a Time-of-Flight (ToF) imaging system for monitoring breath-hold during DIBH-RT. The accuracy of an Argos P330 3D ToF camera (Bluetechnix, Austria) was evaluated for patient setup verification and intra-fraction monitoring among 13 DIBH-RT left breast cancer patients. The ToF imaging was performed simultaneously with in-room cone beam computed tomography (CBCT) and electronic portal imaging device (EPID) imaging systems during patient setup and treatment delivery, respectively. Patient surface depths (PSD) during setup were extracted from the ToF and the CBCT images during free breathing and DIBH using MATLAB (MathWorks, Natick, MA) and the chest surface displacement were compared. The mean difference ± standard deviation, correlation coefficient, and limit of agreement between the CBCT and ToF were 2.88 ± 5.89 mm, 0.92, and - 7.36, 1.60 mm, respectively. The breath-hold stability and reproducibility were estimated using the central lung depth extracted from the EPID images during treatment and compared with the PSD from the ToF. The average correlation between ToF and EPID was - 0.84. The average intra-field reproducibility for all the fields was within 2.70 mm. The average intra-fraction reproducibility and stability were 3.74 mm, and 0.80 mm, respectively. The study demonstrated the feasibility of using ToF camera for monitoring breath-hold during DIBH-RT and shows good breath-hold reproducibility and stability during the treatment delivery.

Linac-Based Ultrahypofractionated Partial Breast Irradiation (APBI) in Low-Risk Breast Cancer: First Results of a Monoinstitutional Observational Analysis

Purpose: For adjuvant radiotherapy of low-risk breast cancer after breast-conserving surgery, there have been many trials of hypofractionation and partial breast irradiation (PBI) over the years, with proven mild long-term toxicity. The aim of this study was to introduce a short-course dose-adapted concept, proven in whole breast irradiation (WBI) for use in accelerated partial breast irradiation (APBI), while monitoring dosimetric data and toxicity. Methods: From April 2020 to March 2022, 61 patients with low-risk breast cancer or ductal carcinoma in situ (DCIS) were treated at a single institution with percutaneous APBI of 26 Gy in five fractions every other day after breast-conserving surgery. Dosimetric data for target volume and organs at risk were determined retrospectively. Acute toxicity was evaluated. Results: The target volume of radiotherapy comprised an average of 19% of the ipsilateral mamma. The burden on the heart and lungs was very low. The mean cardiac dose during irradiation of the left breast was only 0.6 Gy. Two out of three patients remained without any acute side effects. Conclusions: Linac-based APBI is an attractive treatment option for patients with low-risk breast cancer in whom neither WBI nor complete omission of radiotherapy appears to be an adequate alternative.

Surface-guided DIBH radiotherapy for left breast cancer: impact of different thresholds on intrafractional motion monitoring and DIBH stability

PURPOSE

To compare two left breast cancer patient cohorts (tangential vs. locoregional deep-inspiration breath-hold - DIBH treatment) with different predefined beam gating thresholds and to evaluate their impact on motion management and DIBH stability.

METHODS

An SGRT-based clinical workflow was adopted for the DIBH treatment. Intrafractional monitoring was performed by tracking both the respiratory signal and the real-time displacement between the isocenter on the daily reference surface and on the live surface ("SGRT shift"). Beam gating tolerances were 5 mm/4 mm for the SGRT shifts and 5 mm/3 mm for the gating window amplitude for breast tangential and breast + lymph nodes locoregional treatments, respectively. A total of 24 patients, 12 treated with a tangential technique and 12 with a locoregional technique, were evaluated for a total number of 684 fractions. Statistical distributions of SGRT shift and respiratory signal for each treatment fraction, for each patient treatment, and for the two population samples were generated.

RESULTS

Lateral cumulative distributions of SGRT shifts for both locoregional and tangential samples were consistent with a null shift, whereas longitudinal and vertical ones were slightly negative (mean values < 1 mm). The distribution of the percentage of beam on time with SGRT shift > 3 mm, > 4 mm, or > 5 mm was extended toward higher values for the tangential sample than for the locoregional sample. The variability in the DIBH respiration signal was significantly greater for the tangential sample.

CONCLUSION

Different beam gating thresholds for surface-guided DIBH treatment of left breast cancer can impact motion management and DIBH stability by reducing the frequency of the maximum SGRT shift and increasing respiration signal stability when tighter thresholds are adopted.

Three-dimensional conformal radiotherapy (3D-CRT) vs. volumetric modulated arc therapy (VMAT) in deep inspiration breath-hold (DIBH) technique in left-sided breast cancer patients-comparative analysis of dose distribution and estimation of projected secondary cancer risk

PURPOSE

The purpose of this study was to compare two techniques of irradiation of left-sided breast cancer patients who underwent breast-conserving surgery, three-dimensional conformal radiotherapy technique (3D-CRT) and volumetric modulated arc therapy (VMAT), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim of the study was estimation of the projected risk of radiation-induced secondary cancer for both radiotherapy techniques.

MATERIALS AND METHODS

For 25 patients who underwent CT simulation in deep inspiration breath-hold (DIBH), three treatment plans were generated: one using a three-dimensional conformal radiotherapy technique and two using volumetric modulated arc therapy. First VMAT-DIBH geometry consisted of three partial arcs (ARC-DIBH 3A) and second consisted of four partial arcs (ARC-DIBH 4A). Cumulative dose-volume histograms (DVHs) were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], ipsilateral and contralateral lung [IL, CL], and contralateral breast [CB]). Normal tissue complication probabilities (NTCPs) and organ equivalent doses (OEDs) were calculated using the differential DVHs. Excess absolute risks (EARs) for second cancers were estimated using Schneider's full mechanistic dose-response model.

RESULTS

All plans fulfilled the criterium for PTV V95% ≥ 95%. The PTV coverage, homogeneity, and conformity indices were significantly better for VMAT-DIBH. VMAT showed a significantly increased mean dose and V5Gy for all OARs, but reduced LAD D_max by 15 Gy. For IL, CL, and CB, the 3D-CRT DIBH method achieved the lowest values of EAR: 28.38 per 10,000 PYs, 2.55 per 10,000 PYs, and 4.48 per 10,000 PYs (p < 0.001), compared to 40.29 per 10,000 PYs, 15.62 per 10,000 PYs, and 23.44 per 10,000 PYs for ARC-DIBH 3A plans and 41.12 per 10,000 PYs, 15.59 per 10,000 PYs, and 22.73 per 10,000 PYs for ARC-DIBH 4A plans. Both techniques provided negligibly low NTCPs for all OARs.

CONCLUSION

The study shows that VMAT-DIBH provides better OAR sparing against high doses. However, the large low-dose-bath (≤ 5 Gy) is still a concern due to the fact that a larger volume of normal tissues exposed to lower doses may increase a radiation-induced risk of secondary cancer.

Safely completed radiotherapy in a patient with breast cancer and right axillary vein approach cardiac pacemaker implantation: A case report

Pacemaker implantation is becoming increasingly common in patients with breast cancer. Comprehensive treatment options, such as surgery, chemotherapy, radiation therapy, targeted therapy and immunotherapy, have greatly improved the prognosis of patients with breast cancer. In particular, radiotherapy is an important means of comprehensive breast cancer treatment that can reduce recurrence and prolong survival in high-risk patients who underwent mastectomy. The pacemaker electrical pulse generator is typically implanted subcutaneously in the left subclavian area above the pectoral muscle through the subclavian vein. The present report implemented a new method of 'temporary pacemaker electrode and permanent artificial pacemaker placement' through the right axillary vein in a patient with breast cancer. An electrical pulse generator was placed in the right subcutaneous subclavian tissue. The pacemaker was placed under the right clavicle, and the pacemaker was included as organ at risk (OAR). Dose of planning organ at risk volume (PRV) with additional 6 mm margin to the pacemaker was limited during radiotherapy planning design. This patient with breast cancer, who was also complicated with other underlying comorbidities (such as atrial fibrillation, coronary atherosclerosis, cardiac insufficiency, hypertension, type 2 diabetes mellitus) and implanted with a cardiac pacemaker, was treated with safe (means that the patient has not developed heart disease because of the pacemaker problem) and effective (tumor can be effectively controlled under the condition that the pacemaker does not malfunction) radiotherapy. At present, the patient has successfully completed radiation therapy for breast cancer with no recurrence or metastasis. To the best of our knowledge, the present report is the first to document this application, demonstrating the treatment of a patient with breast cancer and cardiac pacemaker implantation, which is worthy of further study and continuous improvement in clinical practice.

ESO-ESMO fifth international consensus guidelines for breast cancer in young women (BCY5)

We dedicate this manuscript in memory of a dear friend and colleague Bella Kaufman. The fifth International Consensus Symposium for Breast Cancer in Young Women (BCY5) took place virtually in October 2020, organized by the European School of Oncology (ESO) and the European Society of Medical Oncology (ESMO). Consensus recommendations for the management of breast cancer in young women were updated from BCY4 with incorporation of new evidence to inform the guidelines. Areas of research priorities as well as specificities in different geographic and minority populations were identified. This manuscript summarizes the ESO-ESMO international consensus recommendations, which are also endorsed by the European Society of Breast Specialists (EUSOMA).

Four irradiation and three positioning techniques for whole-breast radiotherapy: Is sophisticated always better?

PURPOSE

We report on a dosimetrical study of three patient positions (supine, prone dive, and prone crawl) and four irradiation techniques for whole-breast irradiation (WBI): wedged-tangential fields (W-TF), tangential-field intensity-modulated radiotherapy (TF-IMRT), multi-beam IMRT (MB-IMRT), and intensity-modulated arc therapy (IMAT). This is the first study to evaluate prone crawl positioning in WBI and the first study to quantify dosimetrical and anatomical differences with prone dive positioning.

METHODS

We analyzed five datasets with left- and right-sided patients (n = 51). One dataset also included deep-inspiration breath hold (DIBH) data. A total of 252 new treatment plans were composed. Dose-volume parameters and indices of conformity were calculated for the planning target volume (PTV) and organs-at-risk (OARs). Furthermore, anatomical differences among patient positions were quantified to explain dosimetrical differences.

RESULTS

Target coverage was inferior for W-TF and supine position. W-TF proved overall inferior, and IMAT proved foremost effective in supine position. TF-IMRT proved competitive to the more demanding MB-IMRT and IMAT in prone dive, but not in prone crawl position. The lung-sparing effect was overall confirmed for both prone dive and prone crawl positioning and was largest for prone crawl. For the heart, no differences were found between prone dive and supine positioning, whereas prone crawl showed cardiac advantages, although minor compared to the established heart-sparing effect of DIBH. Dose differences for contralateral breast were minor among the patient positions. In prone crawl position, the ipsilateral breast sags deeper and the PTV is further away from the OARs than in prone dive position.

CONCLUSIONS

The prone dive and prone crawl position are valid alternatives to the supine position in WBI, with largest advantages for lung structures. For the heart, differences are small, which establishes the role of DIBH in different patient positions. These results may be of particular interest to radiotherapy centers with limited technical resources.

Breast Cancer in Geriatric Patients: Current Landscape and Future Prospects

Breast cancer is the most common cancer diagnosed among women worldwide and more than half are diagnosed above the age of 60 years. Life expectancy is increasing and the number of breast cancer cases diagnosed among older women are expected to increase. Undertreatment, mostly due to unjustifiable fears of advanced-age and associated comorbidities, is commonly practiced in this group of patients who are under-represented in clinical trials and their management is not properly addressed in clinical practice guidelines. With modern surgery and anesthesia, breast surgeries are considered safe and is usually associated with very low complication rates, regardless of extent of surgery. However, oncoplastic surgery and management of the axilla can be tailored based on patients'- and disease-related factors. Most of chemotherapeutic agents, along with targeted therapy and anti-Human epidermal growth factor receptor-2 (HER2) drugs can be safely given for older patients, however, dose adjustment and close monitoring of potential adverse events might be needed. The recently introduced cyclin-D kinase (CDK) 4/6-inhibitors in combination with aromatase inhibitors (AI) or fulvestrant, which changed the landscape of breast cancer therapy, are both safe and effective in older patients and had substituted more aggressive and potentially toxic interventions. Despite its proven efficacy, adjusting or even omitting adjuvant radiation therapy, at least in low-risk older patients, is safe and frequently practiced. In this paper, we review existing data related to breast cancer management among older patients across the continuum; from resection of the primary tumor through adjuvant chemotherapy, radiation and endocrine therapy up to the management of recurrent and advanced-stage disease.

Comparison of fulfilling the criteria for critical organs in irradiation of patients with breast cancer using the deep inspiration breath-hold and free breathing techniques

Introduction: The aim of the study was to evaluate organ-at-risk dose sparing in treatment plans for patients with left-sided breast cancer irradiated with Deep Inspiration Breath Hold (DIBH) and Free Breathing (FB) techniques.

Material and methods: Twenty patients with left-sided breast cancer were analyzed and divided into two groups. Group A included 10 patients with non-metastatic breast cancer, while group B involved 10 patients with metastatic breast cancer spreading to regional lymph nodes. All patients went through the DIBH coaching. For planning purposes, CT scans were obtained in both DIBH and FB. Mean heart dose (Dmean,heart), mean heart volume receiving 50% of the prescribed dose (V50), V20 (V20L.lung), V10 (V10L.lung) and V5 for left lung (V5L.lung), the volume of the PTV receiving a dose greater than or equal to 95% of the prescribed dose (V95 [%]), the maximum point dose (Dmax), and the volume of PTV receiving 107% of the prescribed dose were reported.

Results: In all 20 analyzed pairs of plans, a reduction by more than half in the mean heart dose in DIBH technique plans was achieved, as well as a significant reduction was found in DIBH plans for the heart V50. In 19 patients, the use of the DIBH technique also reduced the volume of the left lung receiving doses of 20 Gy, 10 Gy, and 5 Gy compared to the FB technique.

Conclusions: Dosimetric analysis showed that the free breathing plans don’t fulfill the criteria for a mean heart dose (group B) and the left lung receiving a 20 Gy dose (group A) compared to the DIBH plans. Radiation therapy of left breast cancer with the use of the DIBH technique results in a significant dose reduction in the heart and also reduces the dose in the left lung in the majority of patients, compared to the FB procedure.

Retrospective Analysis for Dose Reduction to Organs at Risk with New Personalized Breast Holder (PERSBRA) in Left Breast IMRT

This study evaluated dose differences in normal organs at risk, such as the lungs, heart, left anterior descending artery (LAD), right coronary artery, left ventricle, and right breast under personalized breast holder (PERSBRA), when using intensity-modulated radiation therapy (IMRT). This study evaluated the radiation protection offered by PERSBRA in left breast cancer radiation therapy. Here, we retrospectively collected data from 24 patients with left breast cancer who underwent breast-conserving surgery as well as IMRT radiotherapy. We compared the dose differences in target coverage and organs at risk with and without PERSBRA. For target coverage, tumor prescribed dose 95% coverage, conformity index, and homogeneity index were evaluated. For organs at risk, we compared the mean heart dose, mean left ventricle dose, LAD maximum and mean dose, mean left lung receiving 20 Gy, 10 Gy, and 5 Gy of left lung volume, maximum and mean coronary artery of the right, maximum of right breast, and mean dose. Good target coverage was achieved with and without PERSBRA. When PERSBRA was used with IMRT, the mean dose of the heart decreased by 42%, the maximum dose of LAD decreased by 26.4%, and the mean dose of LAD decreased by 47.0%. The mean dose of the left ventricle decreased by 54.1%, the volume (V₂₀) of the left lung that received 20 Gy decreased by 22.8%, the volume (V₁₀) of the left lung that received 10 Gy decreased by 19.8%, the volume (V₅) of the left lung that received 5 Gy decreased by 15.7%, and the mean dose of the left lung decreased by 23.3%. Using PERSBRA with IMRT greatly decreases the dose to organs at risk (left lung, heart, left ventricle, and LAD). This study found that PERSBRA with IMRT can achieve results similar to deep inspiration breath-hold radiotherapy (DIBH) in terms of reducing the heart radiation dose and the risk of developing heart disease in patients with left breast cancer who cannot undergo DIBH.

Volumetric modulated arc therapy (VMAT): a review of clinical outcomes—what is the clinical evidence for the most effective implementation?

Modern conformal radiation therapy using techniques such as modulation, image guidance and motion management have changed the face of radiotherapy today offering superior conformity, efficiency, and reproducibility to clinics worldwide. This review assesses the impact of these advanced radiotherapy techniques on patient toxicity and survival rates reported from January 2017 to September 2020. The main aims are to establish if dosimetric and efficiency gains correlate with improved survival and reduced toxicities and to answer the question ‘What is the clinical evidence for the most effective implementation of VMAT?’. Compared with 3DCRT, improvements have been reported with VMAT in prostate, locally advanced cervical carcinoma and various head and neck applications, leading to the shift in technology to VMAT. Other sites such as thoracic neoplasms and nasopharyngeal carcinomas have observed some improvement with VMAT although not in line with improved dosimetric measures, and the burden of toxicity and the incidence of cancer related deaths remain high, signaling the need to further mitigate toxicity and increase survival. As technological advancement continues, large randomised long-term clinical trials are required to determine the way-forward and offer site-specific recommendations. These studies are usually expensive and time consuming, therefore utilising pooled real-world data in a prospective nature can be an alternative solution to comprehensively assess the efficacy of modern radiotherapy techniques.

Comparison of Heart and Lung Doses According to Tumor Bed Boost Techniques in Early-Stage Left-Sided Breast Cancer: Simultaneous Integrated Boost versus Sequential Boost

Background and Objectives: The boost dose to the tumor bed after whole breast irradiation (WBI) can be divided into sequential boost (SEQ) and simultaneous integrated boost (SIB). SIB using modern radiation therapy (RT) techniques, such as volumetric modulated arc therapy, allow the delivery of a highly conformal dose to the target volume and has a salient ability to spare at-risk organs. This study aimed to compare the radiation dose delivered to the heart and lungs according to boost technique and tumor bed location. Materials and Methods: RT planning data of 20 patients with early-stage left-sided breast cancer were used in this study. All patients were treated with volumetric modulated arc therapy after breast-conserving surgery with a sentinel lymph node biopsy. For each patient, two different plans, whole breast irradiation with simultaneous integrated boost (WBI-SIB) and sequential boost after WBI (WBI-SEQ), were generated. To compare the dose received by each organ at risk (OAR), dose-volume histogram data were analyzed. The mean dose (Dmean) and volume of each organ that received x Gy (Vx) were calculated and compared. Results: For the heart, the V10 was lower for the WBI-SIB plan than for the WBI-SEQ plan (5.223 ± 1.947% vs. 6.409 ± 2.545%, p = 0.008). For the left lung, the V5 was lower in the WBI-SIB plan than for the WBI-SEQ plan (27.385 ± 3.871% vs. 32.092 ± 3.545%, p < 0.001). The Dmean for the heart and left lung was lower for the WBI-SIB plan than for the WBI-SEQ plan (heart: 339.745 ± 46.889 cGy vs. 413.030 ± 52.456 cGy, p < 0.001; left lung: 550.445 ± 65.094 cGy vs. 602.270 ± 55.775 cGy, p < 0.001). Conclusions: The WBI-SIB plan delivered lower radiation doses to the heart and left lung than the WBI-SEQ plan in terms of Dmean and low-dose volume in hypofractionated RT of early-stage left-sided breast cancer patients. Furthermore, a large radiation dose per day may be advantageous, considering the radiobiologic aspects of breast cancer. Long-term follow-up data are needed to determine whether the dosimetric advantages of the WBI-SIB plan can lead to clinically improved patient outcomes and reduced late side effects.

Incidental irradiation of the regional lymph nodes during deep inspiration breath-hold radiation therapy in left-sided breast cancer patients: a dosimetric analysis

Background

Radiotherapy using the deep inspiration breath-hold (DIBH) technique compared with free breathing (FB) can achieve substantial reduction of heart and lung doses in left-sided breast cancer cases. The anatomical organ movement in deep inspiration also cause unintended exposure of locoregional lymph nodes to the irradiation field.

Methods

From 2017–2020, 148 patients with left-sided breast cancer underwent breast conserving surgery (BCS) or mastectomy (ME) with axillary lymph node staging, followed by adjuvant irradiation in DIBH technique. Neoadjuvant or adjuvant systemic therapy was administered depending on hormone receptor and HER2-status.

CT scans in FB and DIBH position with individual coaching and determination of the breathing amplitude during the radiation planning CT were performed for all patients. Intrafractional 3D position monitoring of the patient surface in deep inspiration and gating was performed using Sentinel and Catalyst HD 3D surface scanning systems (C-RAD, Catalyst, C-RAD AB, Uppsala, Sweden). Three-dimensional treatment planning was performed using standard tangential treatment portals (6 or 18 MV). The delineation of ipsilateral locoregional lymph nodes was done on the FB and the DIBH CT-scan according to the RTOG recommendations.

Results

The mean doses (D_mean) in axillary lymph node (AL) level I, II and III in DIBH were 32.28 Gy (range 2.87–51.7), 20.1 Gy (range 0.44–53.84) and 3.84 Gy (range 0.25–39.23) vs. 34.93 Gy (range 10.52–50.40), 16.40 Gy (range 0.38–52.40) and 3.06 Gy (range 0.21–40.48) in FB (p < 0.0001). Accordingly, in DIBH the D_mean for AL level I were reduced by 7.59%, whereas for AL level II and III increased by 22.56% and 25.49%, respectively.

The D_mean for the supraclavicular lymph nodes (SC) in DIBH was 0.82 Gy (range 0.23–4.11), as compared to 0.84 Gy (range 0.22–10.80) with FB (p = 0.002). This results in a mean dose reduction of 2.38% in DIBH.

The D_mean for internal mammary lymph nodes (IM) was 12.77 Gy (range 1.45–39.09) in DIBH vs. 11.17 Gy (range 1.34–44.24) in FB (p = 0.005). This yields a mean dose increase of 14.32% in DIBH.

Conclusions

The DIBH technique may result in changes in the incidental dose exposure of regional lymph node areas.

Dosimetric Evaluation of Incidental Irradiation to the Internal Mammary Chain After Surgery in Breast Cancer Patients

Background and Purpose

The low rate of internal mammary node (IMN) recurrence was attributed to systemic therapy and internal mammary chain (IMC) coverage by the tangential fields of irradiation. This study aimed to evaluate the incidental irradiation dose to the IMC in breast cancer patients after surgery and to estimate the clinical predictive parameters affecting the magnitude of the IMC.

Materials and Methods

A total of 138 patients treated with postmastectomy radiotherapy and 210 patients undergoing radiotherapy after breast-conserving surgery (BCS) in our hospital were retrospectively analyzed. The mean dose (Dmean) to the IMC and the first to third intercostal spaces of IMC levels (ICS1–3) were evaluated. We evaluated the IMC coverage according to the type of surgery and whether the ipsilateral supraclavicular fossa (SCF) was included in the irradiation field.

Results

The incidental radiation dose to the IMC was 29.69 Gy, and the dose delivered to the IMC, ICS1, and ICS2 showed a greater coverage in the modified radical mastectomy (MRM) group when compared with the BCS group (32.85 vs. 27.1 Gy, 26.6 vs. 12.5 Gy, 34.63 vs. 30.42 Gy). The dose delivered to ICS3 showed no difference between the MRM and BCS groups (37.41 vs. 36.24 Gy). Furthermore, 131 patients (37.64%) received radiotherapy to the chest wall and ipsilateral SCF. In the univariate analysis, both surgery type and SCF irradiation were parameters affecting the Dmean of incidental radiation to the IMC (r = −0.179, P = 0.001; r = −0.175, P = 0.001). In the multivariate analysis, surgery type was the only correlative factor that affected incidental radiation dose to the IMC (r = –3.534, P = 0.000).

Conclusion

The real influencing factor of incidental dose to the IMC was the surgery form rather than the accession of SCF irradiation.

Anxiety and depression in patients with breast cancer undergoing radiotherapy: the role of intelligence, life history, and social support-preliminary results from a monocentric analysis

Purpose

It is known that the diagnosis of breast cancer often causes anxiety and depression. Radiotherapy of the breast as an obligatory part of a breast-conserving treatment concept can markedly increase these psychological symptoms in many, but not all patients. In this clinical observational study, we aimed at identifying cognitive, health-related and social factors that may either enhance or reduce the emergence of anxiety and depression.

Methods

Using a longitudinal study design with 25 women (mean age: 52.9 years; SD = 10.6; age range 29–70 years) with a first diagnosis of nonmetastatic breast cancer, measures of anxiety, depression, situational emotional states, intelligence, and aspects of social frameworks were assessed before, during, and after radiotherapy of the breast. At 4 time-points, standard and self-constructed questionnaires were used to assess the course of anxiety and depressive symptoms across the radiotherapy intervention.

Results

We found that anxiety is highest immediately before the start of radiation therapy, while the anxiety level was lowest on the day that therapy was completed. Anxiety and depression were enhanced in women with a lifetime history of chronic diseases at all time points of measurement. Moreover, women with high intelligence and low social support had stronger symptoms of depression than women with low intelligence and a stable family background at some time points of measurement. The degree of anxiety was neither related to intelligence nor to social support.

Conclusion

For the first time, we demonstrate empirical pilot data on cognitive and social modulators of anxiety and depression in women with breast cancer over the course of radiotherapy. Our results may help to optimize clinical procedures and thereby reduce symptoms of anxiety and depression in these patients.

Supplementary Information

The online version of this article (10.1007/s00066-022-01904-7) contains supplementary material, which is available to authorized users.

Influence and compensation of patient motion in electromagnetic tracking based quality assurance in interstitial brachytherapy of the breast

PURPOSE

Electromagnetic tracking (EMT) is a versatile and viable technique for various quality assurance (QA) tasks in interstitial brachytherapy (iBT). As the duration of EMT measurements in iBT is on the order of minutes, they can be strongly affected by patient motion, especially breathing, which gives rise to motion artefacts. Since the centrepiece of EMT related QA in iBT is to assess the geometry of the iBT implant or applicator, the absence of adequate motion compensation techniques could impede the use of EMT for QA purposes. A common way to compensate for this is to reference the data to either external or internal reference sensors (ERS, IRS) which are fixated on the patient's body or inside the applicator and therefore move with the patient. The purpose of the presented study is to provide a quantitative and in-depth analysis on the use of reference sensors for motion compensation.

METHODS

First, the need for adequate motion compensation is identified both qualitatively and quantitatively using a phantom subjected to simulated breathing motion. An evaluation routine is developed to assess the influence of motion compensation using reference sensors on the acquired EMT data. The evaluation metric is based on the observed displacement of the EMT sensor from its mean position while dwelling at a dwell position (DP) for a dwell time of 1 s. After that the routine is applied to a cohort of 54 breast cancer patients treated with iBT and the quality of an ERS based compensation approach is assessed. In a subgroup of four patients, an IRS is inserted into the iBT implant and IRS based compensation is compared to the ERS based approach. Moreover, a correlation analysis of the ERS and IRS approach is performed, also including respiratory signals derived from the trajectories of the different reference sensors.

RESULTS

It was found that motion compensation with ERS effectively reduced the mean sensor displacement per DP to median values as low as 0.11 mm in both phantom and patient measurements, which is below the precision of the EMT system (0.48 mm). Compensation using the IRS yielded comparable results and was as good as compensation with ERS. The results obtained from both approaches showed a strong correlation. Also the respiratory signals calculated from the different reference sensors were well correlated in most cases.

CONCLUSION

These results indicate that motion compensation with ERS can effectively remove motion artefacts in EMT data. While compensation with an IRS leads to comparable results, the IRS occupies one catheter whose geometry hence cannot be assessed. The use of ERS has proven to be both effective and practical in clinical routine. This article is protected by copyright. All rights reserved.

Prone versus supine free-breathing for right-sided whole breast radiotherapy

Prone setup has been advocated to improve organ sparing in whole breast radiotherapy without impairing breast coverage. We evaluate the dosimetric advantage of prone setup for the right breast and look for predictors of the gain. Right breast cancer patients treated in 2010-2013 who had a dual supine and prone planning were retrospectively identified. A penalty score was computed from the mean absolute dose deviation to heart, lungs, breasts, and tumor bed for each patient's supine and prone plan. Dosimetric advantage of prone was assessed by the reduction of penalty score from supine to prone. The effect of patients' characteristics on the reduction of penalty was analyzed using robust linear regression. A total of 146 patients with right breast dual plans were identified. Prone compared to supine reduced the penalty score in 119 patients (81.5%). Lung doses were reduced by 70.8%, from 4.8 Gy supine to 1.4 Gy prone. Among patient's characteristics, the only significant predictors were the breast volumes, but no cutoff could identify when prone would be less advantageous than supine. Prone was associated with a dosimetric advantage in most patients. It sets a benchmark of achievable lung dose reduction.Trial registration: ClinicalTrials.gov NCT02237469, HUGProne, September 11, 2014, retrospectively registered.

A Comprehensive Prospective Comparison of Acute Skin Toxicity after Hypofractionated and Normofractionated Radiation Therapy in Breast Cancer

Simple Summary

Moderate hypofractionated radiotherapy (HF) has become the standard fractionation scheme for most breast cancer patients. Despite comprehensive data from large, randomized trials, standardized assessment of patient reported outcome (PRO) and physiological changes after HF are largely missing. In this prospective trial focusing on radiodermatitis, HF and conventional normofractionated radiotherapy (CF) were compared using standardized Skindex-16 questionnaire in addition to CTCAE assessment and ultrasound measurement of the skin. The results of the current study complement and confirm existing evidence that HF leads to a lower degree of acute radiodermatitis and better patient reported outcome compared to CF.

Abstract

The current study aims to determine whether hypofractionated radiotherapy (HF) leads to lower rates of acute radiodermatitis compared to conventional normofractionated radiotherapy (CF). A total of 166 patients with invasive breast cancer or DCIS were included in a prospective cohort study. Evaluation of acute radiodermatitis was obtained before radiotherapy, at the end of the treatment (T1), and 6 weeks after the treatment (T2) using CTCAE (v5.0) scores, the Skindex-16 questionnaire, and ultrasound measurement of the skin. CTCAE and Skindex-16 scores in the CF-group were significantly higher compared to the HF group indicating more pronounced side effects at the end of the treatment (CTCAE: CF-RT 1.0 (IQR: 0.0) vs. HF-RT 0.0 (0.25); p = 0.03; Skindex-16: CF: 20.8 (IQR: 25.8); HF: 8.3 (27.1); p = 0.04). At 6 weeks after the treatment, no significant differences between the two fractionation schemes were observed. Ultrasound based assessment showed that the skin thickness in the treated breast was higher compared to the healthy breast at all time-points. However, no significant difference between HF and CF was seen either at T1 or T2. The current study complements and confirms pre-existing evidence that HF leads to a lower degree of acute radiodermatitis and better patient reported outcome compared to CF at the end of treatment. This should be considered whenever fractionation of adjuvant breast cancer treatment is being discussed.

Mammary Chain Irradiation in Left-Sided Breast Cancer: Can We Reduce the Risk of Secondary Cancer and Ischaemic Heart Disease with Modern Intensity-Modulated Radiotherapy Techniques?

Introduction

The aim of the present study was to estimate the impact of the addition of internal mammary chain (IMC) irradiation in node-positive left-sided breast cancer (BC) patients undergoing regional nodal irradiation (RNI) and comparatively evaluate excess relative and absolute risks of radiation-induced lung cancer/BC and ischaemic heart disease for intensity-modulated radiotherapy (IMRT) versus 3D conformal radiotherapy (3D-CRT).

Methods

Four treatment plans were created (3D-CRT and IMRT -/+ IMC) for each of the 10 evaluated patients, and estimates of excess relative risk (ERR) and 10-year excess absolute risk (EAR) were calculated for radiation-induced lung cancer/BC and coronary events using linear, linear-exponential and plateau models.

Results

The addition of IMC irradiation to RNI significantly increased the dose exposure of the heart, lung and contralateral breast using both techniques, increasing ERR for secondary lung cancer (58 vs. 44%, p = 0.002), contralateral BC (49 vs. 31%, p = 0.002) and ischaemic heart disease (41 vs. 27%, p = 0.002, IMRT plans). IMRT significantly reduced the mean cardiac dose and mean lung dose as compared to 3D-CRT, decreasing ERR for major coronary events (64% 3D-CRT vs. 41% IMRT, p = 0.002) and ERR for secondary lung cancer (75 vs. 58%, p = 0.004) in IMC irradiation, without a significant impact on secondary contralateral BC risks.

Conclusion

Although IMC irradiation has been shown to increase survival rates in node-positive BC patients, it increased dose exposure of organs at risk in left-sided BC, resulting in significantly increased risks for secondary lung cancer/contralateral BC and ischaemic heart disease. In this setting, the adoption of IMRT seems advantageous when compared to 3D-CRT.

Radiation Induces Valvular Interstitial Cell Calcific Response in an in vitro Model of Calcific Aortic Valve Disease

Background: Mediastinal ionizing radiotherapy is associated with an increased risk of valvular disease, which demonstrates pathological hallmarks similar to calcific aortic valve disease (CAVD). Despite advances in radiotherapy techniques, the prevalence of comorbidities such as radiation-associated valvular disease is still increasing due to improved survival of patients receiving radiotherapy. However, the mechanisms of radiation-associated valvular disease are largely unknown. CAVD is considered to be an actively regulated disease process, mainly controlled by valvular interstitial cells (VICs). We hypothesize that radiation exposure catalyzes the calcific response of VICs and, therefore, contributes to the development of radiation-associated valvular disease.

Methods and Results: To delineate the relationship between radiation and VIC behavior (morphology, calcification, and matrix turnover), two different in vitro models were established: (1) VICs were cultured two-dimensional (2D) on coverslips in control medium (CM) or osteogenic medium (OM) and irradiated with 0, 2, 4, 8, or 16 Gray (Gy); and (2) three-dimensional (3D) hydrogel system was designed, loaded with VICs and exposed to 0, 4, or 16 Gy of radiation. In both models, a dose-dependent decrease in cell viability and proliferation was observed in CM and OM. Radiation exposure caused myofibroblast-like morphological changes and differentiation of VICs, as characterized by decreased αSMA expression. Calcification, as defined by increased alkaline phosphatase activity, was mostly present in the 2D irradiated VICs exposed to 4 Gy, while after exposure to higher doses VICs acquired a unique giant fibroblast-like cell morphology. Finally, matrix turnover was significantly affected by radiation exposure in the 3D irradiated VICs, as shown by decreased collagen staining and increased MMP-2 and MMP-9 activity.

Conclusions: The presented work demonstrates that radiation exposure enhances the calcific response in VICs, a hallmark of CAVD. In addition, high radiation exposure induces differentiation of VICs into a terminally differentiated giant-cell fibroblast. Further studies are essential to elucidate the underlying mechanisms of these radiation-induced valvular changes.

A dosimetric and radiobiological evaluation of VMAT following mastectomy for patients with left-sided breast cancer

Background

To compare the dosimetric, normal tissue complication probability (NTCP), secondary cancer complication probabilities (SCCP), and excess absolute risk (EAR) differences of volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for left-sided breast cancer after mastectomy.

Methods and materials

Thirty patients with left-sided breast cancer treated with post-mastectomy radiation therapy (PMRT) were randomly enrolled in this study. Both IMRT and VMAT treatment plans were created for each patient. Planning target volume (PTV) doses for the chest wall and internal mammary nodes, PTV1, and PTV of the supraclavicular nodes, PTV2, of 50 Gy were prescribed in 25 fractions. The plans were evaluated based on PTV1 and PTV2 coverage, homogeneity index (HI), conformity index, conformity number (CN), dose to organs at risk, NTCP, SCCP, EAR, number of monitors units, and beam delivery time.

Results

VMAT resulted in more homogeneous chest wall coverage than did IMRT. The percent volume of PTV1 that received the prescribed dose of VMRT and IMRT was 95.9 ± 1.2% and 94.5 ± 1.6%, respectively (p < 0.001). The HI was 0.11 ± 0.01 for VMAT and 0.12 ± 0.02 for IMRT, respectively (p = 0.001). The VMAT plan had better conformity (CN: 0.84 ± 0.02 vs. 0.78 ± 0.04, p < 0.001) in PTV compared with IMRT. As opposed to IMRT plans, VMAT delivered a lower mean dose to the ipsilateral lung (11.5 Gy vs 12.6 Gy) and heart (5.2 Gy vs 6.0 Gy) and significantly reduced the V₅, V₁₀, V_20, V_30, and V₄₀ of the ipsilateral lung and heart; only the differences in V₅ of the ipsilateral lung did not reach statistical significance (p = 0.409). Although the volume of the ipsilateral lung and heart encompassed by the 2.5 Gy isodose line (V_2.5) was increased by 6.7% and 7.7% (p < 0.001, p = 0.002), the NTCP was decreased by 0.8% and 0.6%, and SCCP and EAR were decreased by 1.9% and 0.1% for the ipsilateral lung. No significant differences were observed in the contralateral lung/breast V_2.5, V_5, V₁₀, V₂₀, mean dose, SCCP, and EAR. Finally, VMAT reduced the number of monitor units by 31.5% and the treatment time by 71.4%, as compared with IMRT.

Conclusions

Compared with IMRT, VMAT is the optimal technique for PMRT patients with left-sided breast cancer due to better target coverage, a lower dose delivered, NTCP, SCCP, and EAR to the ipsilateral lung and heart, similar doses delivered to the contralateral lung and breast, fewer monitor units and a shorter delivery time.

Harmonization of breast cancer radiotherapy treatment planning in the Netherlands

PURPOSE

The aim was to reach consensus in The Netherlands on which parameters should be used to evaluate breast cancer radiotherapy (RT) plans.

MATERIALS AND METHODS

A Benchmark Case with delineated planning target volumes (PTVs) and Organs At Risk (OARs) was sent to all Dutch radiotherapy centres in combination with a questionnaire, with the request to generate RT plans prescribing 15 times 2.67 Gy for four different treatment indications according to the institutional irradiation technique. The plans and accompanying questionnaire answers were analysed using descriptive statistics. These results, together with a harmonisation proposal, were sent to all centres. The proposal was discussed at a meeting of the Dutch Society of Radiation Oncology breast cancer platform. Distinct parameters were accepted if consensus on them was reached.

RESULTS

19 out of 20 Dutch departments participated in this study. PTV coverage varied considerably, with D98% between 63% and 99% for the breast and between 37% and 97% for the internal mammary nodes (IMN). Also substantial OAR dose differences were observed, with e.g. mean heart doses ranging between 1.85 Gy and 5.42 Gy in case the IMN were included in the PTV. For evaluation of the PTVs D98%, D2% and Dmean were chosen to report on, with target values of ≥ 95% (90% for the PTV_IMN), ≤ 107%, and 99-101%, respectively. For OARs, consensus was reached on the parameters to be evaluated, without target values: Dmean of the heart, Dmean and V5% of the lungs, and in case of periclavicular radiotherapy V30Gy of the thyroid gland. For patients younger than 40 years a contralateral mean breast dose of ≤ 1 Gy was agreed upon.

CONCLUSION

A new Dutch consensus guideline for evaluation of breast cancer RT plans has been established.

The advantages of abdominal compression with shallow breathing during left-sided postmastectomy radiotherapy by Helical TomoTherapy

BACKGROUND

Left-sided post-mastectomy radiotherapy (PMRT) certainly precedes some radiation dose to the cardiopulmonary organs causing many side effects. To reduce the cardiopulmonary dose, we created a new option of the breathing adapted technique by using abdominal compression applied with a patient in deep inspiration phase utilizing shallow breathing. This study aimed to compare the use of abdominal compression with shallow breathing (ACSB) with the free breathing (FB) technique in the left-sided PMRT.

MATERIALS AND METHODS

Twenty left-sided breast cancer patients scheduled for PMRT were enrolled. CT simulation was performed with ACSB and FB technique in each patient. All treatment plans were created on a TomoTherapy planning station. The target volume and dose, cardiopulmonary organ volume and dose were analyzed. A linear correlation between cardiopulmonary organ volumes and doses were also tested.

RESULTS

Regarding the target volumes and dose coverage, there were no significant differences between ACSB and FB technique. For organs at risk, using ACSB resulted in a significant decrease in mean (9.17 vs 9.81 Gy, p<0.0001) and maximum heart dose (43.79 vs 45.45 Gy, p = 0.0144) along with significant reductions in most of the evaluated volumetric parameters. LAD doses were also significantly reduced by ACSB with mean dose 19.24 vs 21.85 Gy (p = 0.0036) and the dose to 2% of the volume (D2%) 34.46 vs 37.33 Gy (p = 0.0174) for ACSB and FB technique, respectively. On the contrary, the lung dose metrics did not show any differences except the mean V5 of ipsilateral lung. The positive correlations were found between increasing the whole lung volume and mean heart dose (p = 0.05) as well as mean LAD dose (p = 0.041) reduction.

CONCLUSIONS

The ACSB technique significantly reduced the cardiac dose compared with the FB technique in left-sided PMRT treated by Helical TomoTherapy. Our technique is uncomplicated, well-tolerated, and can be applied in limited resource center.

Final analysis of a Multicenter Single-Arm Confirmatory Trial of hypofractionated whole breast irradiation after breast-conserving surgery in Japan: JCOG0906

OBJECTIVE

To evaluate the safety and efficacy of hypofractionated whole breast irradiation for Asian women after breast-conserving surgery. This is an updated report with 5-year follow-up.

METHODS AND MATERIALS

Asian women who had invasive breast cancer with clinical tumor size ≤3 cm, pN0-1c and negative inked margins were enrolled. Hypofractionated whole breast irradiation of 42.56 Gy/16 fractions was delivered, and boost irradiation of 10.64 Gy/4 fractions was added when the surgical margin was ≤5 mm. The primary endpoint was the proportion of grade ≥ 2 late adverse reactions within 3 years. Secondary endpoints included early adverse events, overall survival, disease-free survival, ipsilateral breast relapse-free survival, late adverse reactions and cosmetic outcome. Toxicities were evaluated using CTCAE ver3.0. Cosmetic outcomes were assessed using a 4-point scale and CTCAE ver3.0 for hyper/hypopigmentation, breast nipple/areolar deformity and breast volume/deformity.

RESULTS

Between February 2010 and August 2012, 312 patients were enrolled, and 306 received hypofractionated whole breast irradiation. Median follow-up was 70.5 (range 7.6-88.9) months. The proportion of grade ≥ 2 late adverse reactions within 3 years was 4.3% (90% confidence interval 2.5-6.7%). Grade 2 early adverse events occurred in 38 (12.4%); none had grade 3/4. Five-year overall survival, disease-free survival and ipsilateral breast relapse-free survival were 98.7, 95.4 and 98.0%, respectively. Of the 304 evaluable patients, 29 (9.5%; 95% confidence interval 6.5-13.4%) had grade 2/3 late adverse reactions; none had grade 4/5. At 5 years, 70/289 (24.2%) showed any worsening of breast cosmetic changes.

CONCLUSIONS

Hypofractionated whole breast irradiation is considered a standard treatment for Asian women with margin-negative invasive breast cancer after breast-conserving surgery.

Is it advantageous to use deep inspiration breath hold (DIBH) over free breathing for FAST-Forward dose fractionation scheme in treating carcinoma of left-sided breast? A dosimetric study

Aim:

To study the effect of deep inspiration breath hold (DIBH) on Fast-Forward trial for left-sided breast radiotherapy dosimetrically using tangential field-in-field (FiF), flattening filtered volumetric-modulated arc therapy (FF-VMAT) and flattening filter free volumetric-modulated arc therapy (FFF-VMAT) in comparison with free breathing (FB).

Methods:

Computed tomography images were acquired on 15 patients with carcinoma of left breast in FB and DIBH. Planning target volume (PTV) and organs at risk were contoured on both image sets. Dose of 26 Gy in five daily fractions was prescribed to PTV. FiF, FF-VMAT and FFF-VMAT plans were created in treatment planning system on both FB and DIBH. PTV V95%, V107%, D0·1 cc, CI and HI, heart V1·5 Gy, V7 Gy, lung left V8 Gy, monitor units (MU) and beam ON time were used for evaluation. Different technique analysis in same breathing condition and FB versus DIBH for same planning technique were performed.

Results:

Mean of all 15 patients was reported as mean ± 1 standard deviation. PTV V95% was 97·55 ± 0·10 (FiF), 95·75 ± 0·66 (FF-VMAT) and 96·15 ± 0·46 (FFF-VMAT) in FB while 97·34 ± 0·50 (FiF), 96·03 ± 0·71 (FF-VMAT) and 95·86 ± 0·63 (FFF-VMAT) in DIBH. Heart V7 Gy was 8·53 ± 4·26 (FiF), 8·86 ± 2·20 (FF-VMAT) and 9·27 ± 2·46 (FFF-VMAT) in FB while 6·30 ± 2·98 (FiF), 5·23 ± 2·20 (FF-VMAT) and 4·68 ± 2·01 (FFF-VMAT) in DIBH. p-value of heart V7 Gy between FB and DIBH was 0·278 (FiF), 0·009 (FF-VMAT) and 0·003 (FFF-VMAT). Beam ON time for FFF-VMAT was reduced by 65% (FF-VMAT) and 11% (FiF).

Conclusion:

Conformal dose to PTV was achieved better with VMAT plans. FFF-VMAT was delivered in less time compared to FF-VMAT and FiF for 26 Gy in five fractions. Heart dose can be significantly minimised with DIBH for VMAT plans.