Dosimetric Effect of Thymus on Radiation-Induced Lymphopenia in Breast Cancer Patients Who Received Adjuvant Radiotherapy

Longitudinal Analyses and Predictive Factors of Radiation-Induced Lymphopenia After Postmastectomy Hypofractionated Radiation Therapy for Breast Cancer: A Pooled Cohort Study of 2 Prospective Trials.

Accelerated Adaptation of Ultrahypofractionated Radiation Therapy for Breast Cancer at the Time of the COVID-19 Pandemic

Background: It has been demonstrated that radiation therapy lowers both the death rate from breast cancer and its recurrence. Precise calculation of the radiation dose is crucial for treating the target site as well as protecting vital organs like the heart since large doses of radiation therapy significantly increase patient morbidity and death. Objective: To compare the mean heart dose of radiation in breast cancer patients between breast-conserving surgery versus mastectomy, between different radiotherapy doses and fractionation schedules, and between right and left breast cancer irradiation. Patients and Methods: This is a cross-sectional descriptive retrospective comparative study that was conducted in Baghdad Radiotherapy Center from January 2018 to June 2018, carried on 174 breast cancer patients of different age groups selected randomly and their mean heart dose data collected from their files and database in Baghdad Radiotherapy Center. Results: The overall average of the mean dose was 372 cGy (range from 76.4 to 716.2). The greatest difference in the mean heart dose was between (BCS) patients who received 5000 cGy with regional nodal irradiation and (BCS) patients who received 4005 cGy also with regional nodal irradiation (difference in the mean is 639.8, the P – value <0.001). Regarding the side of breast cancer, the greatest difference in mean heart dose was seen between left and right breast cancer patients who did the same type of surgery (MRM) and received the same dose of radiotherapy (4256 cGy) (difference in the mean is 565cGy and the P – value <0.001). No statistically significant difference in the mean dose between breast-conserving surgery and mastectomy was recorded. Conclusion: The mean heart dose of radiotherapy is significantly increased in left-sided breast cancer irradiation as compared to the right side. A dose of 5000 cGy has the greatest effect on the dose received by the heart, especially in left breast cancer. The type of surgery whether breast-conserving surgery or mastectomy did not affect the mean dose received by the heart. Keywords: Breast cancer, cardiac radiation dose, breast cancer surgery, breast cancer treatment.

The role of radiation therapy in the management of primary breast cancer

Topical Agents for Radiation Dermatitis in Breast Cancer: 50 Shades of Red or Same Old, Same Old?

e12567 Background: Radiation-induced lymphopenia accompanied with radiation therapy is associated with inferior clinical outcomes in a wide variety of solid malignancies. This study aimed to examine the potential determines of radiation-induced lymphocyte decrease and radiation-induced lymphopenia in breast cancer patients who underwent radiotherapy. Methods: Patients with breast cancer treated who underwent radiotherapy were enrolled in University of Hong Kong-Shenzhen Hospital (our cohort). Circulating lymphocyte levels were evaluated within 7 days prior to and end of radiation therapy. Feature groups including clinical data, tumor characteristics, radiotherapy dosimetrics, treatment regiments were also collected. We applied machine learning algorithms (Extreme Gradient Boosting, XGboost) to predict the ratio of lymphocyte level after radiotherapy to baseline lymphocyte level and the event of lymphopenia and compared with Lasso regression approaches. Next, we used Shapley additive explanation (SHAP) to explore the directional contribution of each feature for lymphocyte decrease and lymphopenia. For the purpose of model validation and proof-of-concept validation, an independent cohort of patients enrolled in prospective trial was eligible (IP cohort). Results: A total of 589 patients were enrolled in our cohort and 203 patients in IP cohort. XGboost models which trained in our cohort with performances of a mean RMSE: 0.157 and R2: 53.9% for the ratio of lymphocyte levels; a mean accuracy: 0.757 and ROC-AUC: 0.733 for the lymphopenia events, separately. These models can predict the ratio of lymphocyte levels with a mean RMSE: 0.175 and R2: 47%; predict the lymphopenia events with a mean accuracy: 0.739 and ROC-AUC: 0.737 in the totally independent IP cohort. The feature group of dosimetrics had the largest predictive power with RMSE: 0.192, R2: 29.8%, accuracy: 0.678 and ROC-AUC: 0.667; followed by the group of baseline blood cells with predictive power as RMSE: 0.207, R2: 18.9%, accuracy: 0.669 and ROC-AUC: 0.645. Next, by SHAP value analysis, we investigated that integral dose of the total body, V5 dose, mean lung dose and V20 dose of ipsilateral lung/bilateral lungs were in consequence important promote factors for lymphocyte decrease and for the event of lymphopenia, while the features of baseline monocyte, mean heart dose and tumor size played a role of protection at some extend. Conclusions: In this study, we constructed robust XGboost models for predicting the lymphocyte decrease and the event of lymphopenia in breast cancer patients who underwent radiation therapy. We also applied SHAP analysis for revealing the directional contribution of features. These results are important either for the understanding the contributions of dosimetrics on immune response or for the refine of radiation dosimetrics before treatment in future clinical usages.

A Population-Based Model of Local Control and Survival Benefit of Radiation Therapy for Breast Cancer

Lymphocyte Count Kinetics and the Effect of Different Radiotherapy Techniques on Radiation-Induced Lymphopenia in Patients with Breast Cancer Receiving Hypofractionated Postmastectomy Radiotherapy

MD, FRCS, FRCRMeyerstein Institute of Oncology and Academic Department of Surgery, University College London Hospitals NHS Trust,London, UKIn Time magazine’s extensively researched breast cancerissue (June 10, 2002), one particular quote had a specialresonance for us. In the introduction to a remarkablycomprehensive article, Dr Julie Gralow, an Oncologist atthe Fred Hutchinson Cancer Research Centre in Seattle,stated ‘‘We may be far overtreating our patients… We’venow got women being diagnosed with tumours that wouldprobably never have been treated if we didn’t havemammography. They probably would have lived long,natural, healthy lives never knowing they had breastcancer’’ (J Gralow, quoted in [1]).For some years it has been apparent that, for manypatients, powerful treatment by surgery (even when limitedto tumour excision with breast preservation) together witha 6 week programme of radiation therapy may be morethan sufficient. We already know a good deal (althoughnot of course enough) about the profile of a typical breastcancer patient with low risk of local and distant recur-rence: a small, low or moderate grade tumour, surgicallycompletely excised, positive for oestrogen and/or proges-terone receptors, negative for HER2 and with negativeaxillary nodes. Post-menopausal patients clearly have alower incidence of local recurrence; for example, in thelarge study by Bartelink et al [2], patients over the age of60 years had a rate of local recurrence following 50 Gywhole breast radiation of only 4% (without an additionalboost), the rate reducing still further to 2.5% with anadditional 16 Gy given by electron beam therapy. Forpatients aged 41 to 50 years, the rates were 9.5% and 5.8%,respectively (median follow-up 5.1 years). What’s more, anever increasing number of patients now present with smalltumours (,1 cm) identified on mammographic screening,of whom approximately three-quarters will have oestrogenreceptor (ER)/progesterone receptor (PR) positive tumours,for which targeted hormone therapy with tamoxifen offerssustained long-term benefit for both local and distantrelapse [3, 4]. Using a well tolerated oral aromataseinhibitor such as Anastrazole reduces the risk still further(for both local and distant relapse), also, incidentally,reducing by three-quarters the risk of development of acontralateral primary breast cancer [5].For all these reasons, we strongly support Gralow’sview. Even in younger women known to be at higher riskof relapse, including those with axillary node-positivedisease, the use of systemic adjuvant cytotoxics sharplyreduces the risk of recurrence [3, 4, 6]. For hormonereceptor-positive patients, i.e. the large majority, adjuvanthormone therapy as well as surgical or medical oophor-ectomy all add further benefit [2–4, 6].What is the consequence of Gralow’s observation? Inthe past, it has been regarded as mere flight of fancy toimagine that we can identify patients at such low risk ofrecurrence that a less intensive form of treatment thanlocal surgical excision followed by whole breast irradiationcould be regarded as ‘‘adequate’’. In this sense, thisgeneral policy remains little different in principle from theequally compelling (in its day) policy of radical, then lessdamaging forms of mastectomy – although admittedly,using local excision, breast preservation and post-operativeradiotherapy is generally regarded as more ‘‘humane’’ eventhough attempts at demonstrating an improved quality oflife have been largely elusive [7]. None the less, theevolving history of local treatment for early breast cancerhas centred on an ever increasing recognition of theimportance of breast conservation for body image andcosmesis, an essential requirement for most women. Thishas largely been achieved by the increasing acceptance ofbreast-conserving surgery with post-operative radiotherapy[8]. Yet despite this ready acceptance, recent data from theworld’s largest ever randomized breast cancer study, withexcellent quality control and a high level of expertise,confirm a mastectomy rate approaching 50% [ATACTrialists Group, unpublished data].We believe that the time has come to move on further.For many patients, particularly those presenting over theage of 50 years with small, low grade, ER positive, axillarynode negative tumours, it is surely right to question thenecessity of a lengthy and sometimes damaging course ofradiation therapy. Radiation oncologists who are totallysatisfied with their often excellent cosmetic results and lowrelapse rates following standard treatment should bearin mind the work of the Oxford-based Early BreastCancer Trialists’ Collaborative Group, namely that despitea lower breast cancer cause-specific death rate in irradiatedpatients, the increased mortality for other non-cancercauses wipes out this advantage [9]. The assumption thatthe excess non-cancer-related deaths in this large meta-analysis were due essentially to reliance on older outmodedradiation techniques may be correct – but it remains anassumption only, and considerable additional data attestto the cardiac, pulmonary and neurological dangers ofwhole breast irradiation [10–12]. Moreover, the use ofanthracycline-based chemotherapy regimens apparentlyincreases some of these risks still further [13].

Interpretable deep learning insights: Unveiling the role of 1 Gy volume on lymphopenia after radiotherapy in breast cancer

Low local recurrence rate without postmastectomy radiation in node-negative breast cancer patients with tumors 5 cm and larger

Beyond Mean Heart Dose: Cardiac Metrics for the Modern Era

Risk and severity of SARS-CoV-2 infection in breast cancer patients undergoing a structured infection screening program at the University and Hospital Trust of Verona

Introduction: Breast cancer remains the most frequently diagnosed malignancy among women worldwide, with approximately 2 million new cases annually. Radiotherapy (RT) significantly reduces local recurrence and breast cancer related mortality; however, incidental irradiation of cardiac sub-structures can lead to radiation-induced heart disease (RIHD). Despite substantial advances in treatment planning and dose optimization, a considerable proportion of patients remain at risk of cardiac toxicity. Current evidence suggests a linear relationship between mean heart dose (MHD) and cardiac events, with an excess relative risk of approximately 4–7% per Gy increase in MHD. This narrative review aims to establish evidence regarding dose-response relationships, cardiac substructure sensitivity, modern heart-sparing techniques, early detection strategies, and the balance between oncologic benefit and cardiovascular risk in breast cancer radiotherapy. Methodology: A comprehensive literature search was conducted from January 2015 to September 2025 using the Cochrane Library, PubMed Central, and Google Scholar. Studies involving breast cancer patients treated with adjuvant radiotherapy to the breast/chest wall with or without regional nodal irradiation and reporting cardiac outcomes were included. Over 250 records were identified; after removal of duplicates and screening, 31 relevant studies were incorporated. Landmark randomized trials, meta-analyses, dosimetric studies, and prospective imaging-based investigations were narratively analyzed. The narrative review was synthesized across four domains: epidemiology and risk magnitude, dose-response relationships and substructure dosimetry, impact of modern RT techniques, and early cardiac injury detection and risk stratification. Results: A consistent linear dose-response relationship between MHD and major coronary events was observed, with an excess MHD of approximately 7.4% per Gy. Radiotherapy was associated with a 6.4% increase in 10-year cardiovascular event risk. Randomized trial data by Taylor et al. demonstrated an excess relative risk of 0.04 per Gy for cardiac mortality. Meta-analytic evidence showed that left-sided RT significantly increased the risk of coronary heart disease (RR 1.29) and cardiac death (RR 1.22) compared with right-sided RT. Cardiac substructures, particularly the left anterior descending artery (LAD) and left ventricle (LV), appeared more predictive of ischemic risk than whole-heart dose alone. Dosimetric studies demonstrated that deep inspiration breath-hold (DIBH) reduced LAD maximum and mean doses by 31.7% and 28.1%, respectively, compared with free-breathing plans (p ≤ 0.001), supporting its routine clinical implementation. Advanced techniques such as VMAT achieved acceptable target coverage while facilitating cardiac dose reduction as compared to 3D-CRT. Although RT provides an absolute survival benefit of approximately 4–5% against breast cancer mortality, it is associated with a modest increase in cardiovascular mortality of about 0.2–0.3%, underscoring the importance of individualized risk–benefit assessment. Advanced echocardiographic techniques, including strain imaging, demonstrated early subclinical myocardial dysfunction within six months of RT, highlighting opportunities for early intervention. Conclusion: This review provides an insight into the current prevalence of radiotherapy induced cardiotoxicity in breast cancer patients and most commonly used approaches to possibly alleviate the adverse effects of radiation. Despite clear evidence linking radiation induced cardiotoxicity, a clear consensus on dose constraints, radiotherapy volumes for cardiac sparing is required. Cardio-oncology, as an emerging multidisciplinary field might serve as a bridge in the current gaps of researches on cardio-protection and cardiotoxicity.

The most common malignancy among Indian women is carcinoma of the breast. In the management of breast cancer (BC), radiation therapy (RT) is given to breast or chest wall and supraclavicular lymph nodal (SCLN) area, with at least part of the thyroid receiving RT dose.There is an increased incidence of hypothyroidism (HT) among BC patients after RT involving the SCLN area. Moreover, the incidence of HT in India is higher than in the West. The aim of our study is to dosimetrically evaluate the thyroid doses during RT for BC. This is a single institute prospective study (n = 131). Radiation was planned by three-dimensional conformal radiation therapy (3D-CRT) technique and dose-volume parameters for thyroid gland were noted. The median thyroid gland volume was 7.4 cc. The median of the mean dose to thyroid gland was 2068 cGy, V10 was 42%, and V40 was 33%. In other studies, BC patients with smaller thyroid gland were more prone to HT (volume <8 cc). In our study, we have seen that the median thyroid volume was 7.4 cc. Our study showed a lower mean dose to the thyroid gland and smaller volume thyroid glands than in the literature. As the incidence of HT is higher in India, compared to the west and our patients had small volume thyroid glands, they could be at higher risk of developing HT RT. So BC patients should be monitored for HT and should be given a dose constraint while planning RT.