Predictive factors of radiation-induced skin toxicity in breast cancer patients

Optimising inter-patient image registration for image-based data mining in breast radiotherapy

Background and purpose

Image-based data mining (IBDM) requires spatial normalisation to reference anatomy, which is challenging in breast radiotherapy due to variations in the treatment position, breast shape and volume. We aim to optimise spatial normalisation for breast IBDM.

Materials and methods

Data from 996 patients treated with radiotherapy for early-stage breast cancer, recruited in the REQUITE study, were included. Patients were treated supine (n = 811), with either bilateral or ipsilateral arm(s) raised (551/260, respectively) or in prone position (n = 185). Four deformable image registration (DIR) configurations for extrathoracic spatial normalisation were tested. We selected the best-performing DIR configuration and further investigated two pathways: i) registering prone/supine cohorts independently and ii) registering all patients to a supine reference. The impact of arm positioning in the supine cohort was quantified. DIR accuracy was estimated using Normalised Cross Correlation (NCC), Dice Similarity Coefficient (DSC), mean Distance to Agreement (MDA), 95 % Hausdorff Distance (95 %HD), and inter-patient landmark registration uncertainty (ILRU).

Results

DIR using B-spline and normalised mutual information (NMI) performed the best across all evaluation metrics. Supine-supine registrations yielded highest accuracy (0.98 ± 0.01, 0.91 ± 0.04, 0.23 ± 0.19 cm, 1.17 ± 1.18 cm, 0.51 ± 0.26 cm for NCC, DSC, MDA, 95 %HD, and ILRU), followed by prone-prone and supine-prone registrations. Arm positioning had no significant impact on registration performance. For the best DIR strategy, uncertainty of 0.44 and 0.81 cm in the breast and shoulder regions was found.

Conclusions

B-spline algorithm using NMI and registered supine and prone cohorts independently provides the most optimal spatial normalisation strategy for breast IBDM.

Incidence and severity of acute radiation induced toxicities among breast cancer patients treated with adjuvant radiotherapy at a major cancer treatment center in Ghana

BACKGROUND

Adjuvant radiotherapy after mastectomy or breast conserving surgery (BCS) is the standard of care for majority of patients with breast cancer. This is however associated with mucosal and epidermal toxicity of organs at risk (OARs). Breast cancer patients are exposed to a plethora of wrong perceptions, misinformation and myths concerning the usefulness and adverse effects of radiotherapy. There is paucity of literature on the incidence and severity of radiation-induced acute toxicities experienced by patients with breast cancer in Ghana.

AIM

To assess the occurrence and severity of four main acute radiation-induced toxicities among female breast cancer patients treated with external beam radiotherapy at a major cancer treatment centre in Ghana.

METHODS

Data on the occurrence of acute toxicities among patients was collected from patients' medical records, through a semi-structured questionnaire and via weekly clinical assessments. The Common Terminology Criteria for Adverse Events (CTCAE) grading scale (version 4.0) was used to grade the severity of these toxicities. Descriptive and inferential statistics using an independent two-sampled t-test (two-tailed), one-way analysis of variance (ANOVA), Pearson's Chi-square and Fisher's exact tests were performed.

RESULTS

Dermatitis, fatigue, pharyngitis, and breast (chest) pain were the radiation toxicities found among the breast cancer patients undergoing treatment on the two machines. The mean predominant radiation doses associated with the onset of dermatitis, fatigue, pharyngitis, and chest pain in the breast cancer patients were 22.32 Gy, 22.48 Gy, 13.59 Gy, and 19.27 Gy respectively for treatment with a statistically significant (p = 0.0173). Radiation dermatitis was the most dominant acute radiation toxicity recorded, and its incidence and severity. The range of Fisher's p-values (0.689-0.999) between the acute radiation toxicities with both machines revealed no statistical significance.

CONCLUSION

Radiation dermatitis was the dominant acute toxicity, both in incidence and severity for patients treated. There was no statistical significance in the incidence and severity of acute radiation side effects.

Mepitel film for the prevention of radiation dermatitis: A comprehensive review of its efficacy, side effects, physics measurements, patient- and clinician-reported outcomes

Objective

This review aimed to summarize the benefits, side effects, physics measurements, and patient- and clinician-reported outcomes of Mepitel film (MF) in preventing radiation dermatitis (RD) for cancer patients.

Methods

The online database PubMed was searched from inception to April 15, 2024 with the search terms "Mepitel film" or "Mepitel." Articles of any study design evaluating MF for the prevention of RD were included. Non-human studies were excluded.

Results

The database search identified 119 articles and 13 of them were included in this review. Across these studies, MF was found to be beneficial in reducing RD and improved patient- and clinician-reported outcomes in breast and head and neck cancers. Side effects of MF included itchiness, acne, allergic reaction, tightness, discomfort, and poor film adherence, but patient dropouts were uncommon. MF did not cause a bolus effect or increased skin dose in physics measurements.

Conclusions

MF is a safe and effective intervention for preventing acute RD. It should be recommended in breast cancer patients where the data is more robust. Further research is needed to evaluate MF's efficacy on patients with different skin tones, its cost-effectiveness, and identifying patients who most benefit from MF relative to other effective interventions.

Investigating and Analyzing Prognostic Factors and Their Impact on Recurrent Cervical Cancers

The incidence of cervical cancer in India is significantly high, and the average recurrence age is much less. The standard line of treatment consists of concurrent chemoradiotherapy. If a recurrence occurs, the treatment options or set of interventions are limited and suboptimal. Through this review, we have analyzed and classified the possible prognostic factors for cervical cancer into three broad categories, viz., (a) disease-related factors, (b) patient-related factors, and (c) treatment-related factors. Disease-related factors include tumor histology, tumor size, stage, parametrial involvement (PMI), Prognostic Nutritional Index (PNI), lymphovascular space invasion (LVSI), and nodal status. Patient-related factors include overall treatment time (OTT), nutritional status, hemoglobin level, comorbidities, and age. Treatment-related factors include addition of chemotherapy, techniques of external beam radiotherapy (EBRT), techniques of brachytherapy, and quality assurance for radiation therapy delivery. Out of these, extremely significant prognostic factors were tumor size and stage, nodal status, PMI, nutritional status, and addition of chemotherapy. Impactful factors include younger age, histology, LVSI, associated comorbidities, hemoglobin level, OTT, and patient-specific quality assurance. The factor that is not related or significant is the technique used for EBRT and brachytherapy delivery.

A dosiomics model for prediction of radiation-induced acute skin toxicity in breast cancer patients: machine learning-based study for a closed bore linac

BACKGROUND

Radiation induced acute skin toxicity (AST) is considered as a common side effect of breast radiation therapy. The goal of this study was to design dosiomics-based machine learning (ML) models for prediction of AST, to enable creating optimized treatment plans for high-risk individuals.

METHODS

Dosiomics features extracted using Pyradiomics tool (v3.0.1), along with treatment plan-derived dose volume histograms (DVHs), and patient-specific treatment-related (PTR) data of breast cancer patients were used for modeling. Clinical scoring was done using the Common Terminology Criteria for Adverse Events (CTCAE) V4.0 criteria for skin-specific symptoms. The 52 breast cancer patients were grouped into AST 2 + (CTCAE ≥ 2) and AST 2 - (CTCAE < 2) toxicity grades to facilitate AST modeling. They were randomly divided into training (70%) and testing (30%) cohorts. Multiple prediction models were assessed through multivariate analysis, incorporating different combinations of feature groups (dosiomics, DVH, and PTR) individually and collectively. In total, seven unique combinations, along with seven classification algorithms, were considered after feature selection. The performance of each model was evaluated on the test group using the area under the receiver operating characteristic curve (AUC) and f1-score. Accuracy, precision, and recall of each model were also studied. Statistical analysis involved features differences between AST 2 - and AST 2 + groups and cutoff value calculations.

RESULTS

Results showed that 44% of the patients developed AST 2 + after Tomotherapy. The dosiomics (DOS) model, developed using dosiomics features, exhibited a noteworthy improvement in AUC (up to 0.78), when spatial information is preserved in the dose distribution, compared to DVH features (up to 0.71). Furthermore, a baseline ML model created using only PTR features for comparison with DOS models showed the significance of dosiomics in early AST prediction. By employing the Extra Tree (ET) classifiers, the DOS + DVH + PTR model achieved a statistically significant improved performance in terms of AUC (0.83; 95% CI 0.71-0.90), accuracy (0.70), precision (0.74) and sensitivity (0.72) compared to other models.

CONCLUSIONS

This study confirmed the benefit of dosiomics-based ML in the prediction of AST. However, the combination of dosiomics, DVH, and PTR yields significant improvement in AST prediction. The results of this study provide the opportunity for timely interventions to prevent the occurrence of radiation induced AST.

A Prospective Study Demonstrating Early Prediction of Skin Toxicity From Radiation Therapy Using Radiomic Features From Optical and Infrared Images

PURPOSE

Approximately 90% of patients undergoing breast cancer radiation therapy experience skin toxicities that are difficult to classify and predict ahead of time. A prediction of toxicity at the early stages of the treatment would provide clinicians with a prompt to intervene. The objectives of this study were to evaluate the correlation between skin toxicity and radiomic features extracted from optical and infrared (thermal) images of skin, and to develop a model for predicting a patient's skin response to radiation.

METHODS AND MATERIALS

Optical and infrared breast and chest-wall images were acquired daily during the course of radiation therapy, as well as weekly for 3 weeks after the end of treatment for 20 patients with breast cancer. Skin-toxicity assessments were conducted weekly until the patients' final visit. Skin color and temperature trends from histogram-based and texture-based radiomic features, extracted from the treatment area, were analyzed, reduced, and used in a cross-validation machine learning model to predict the patients' skin toxicity grades.

RESULTS

A set of 9 independent color and temperature features with significant correlation to skin toxicity were identified from 108 features. The cross-validation accuracy of a cubic Support Vector Machine remained >85% and area under the receiver operating characteristic curve remained >0.75, when reducing the input imaging data to include only the sessions with a biologically effective dose not exceeding 30 Gy (approximately the first third to first half of the total treatment dose).

CONCLUSIONS

The quantitative analysis of radiomic features extracted from optical and infrared (thermal) images of skin was shown to be promising for predicting skin toxicities.

Randomized Pilot Study of a Keratin-based Topical Cream for Radiation Dermatitis in Breast Cancer Patients

Purpose: Radiotherapy (RT) is commonly used in the treatment of breast cancer and often, despite advances in fractionated dosing schedules, produces undesirable skin toxicity. The purpose of this study was to evaluate the feasibility of using a keratin-based topical cream, KeraStat® Cream (KC; KeraNetics, Inc., Winston Salem, NC, USA) to manage the symptoms of radiation dermatitis (RD) in breast cancer patients undergoing RT. Materials and Methods: A total of 24 subjects were enrolled on this single-center, randomized, open-label study. Participants were randomly assigned to KC or standard of care (SOC, patient's choice of a variety of readily available creams or moisturizers). Patients were asked to apply the assigned treatment to the irradiated area twice daily, beginning with day 1 of RT, through 30 days post-RT. The primary outcome was compliance of use. Secondary outcomes included safety and tolerability of KC, as well as RD severity assessed using the Radiation Therapy Oncology Group (RTOG) scale and the patient-reported Dermatology Life Quality Index (DLQI). Results: All subjects in the KC group were assessed as compliant with no adverse events. The rate of RTOG Grade 2 RD was lower in the KC group (30.8%) compared to the SOC group (54.5%, P = .408). At the final RT visit, the mean RTOG RD score was lower in the KC group (1.0) versus the SOC group (1.4). Similarly, patient-reported quality of life measured by the DLQI at the end of RT was improved in the KC group (mean 4.25, small effect) versus the SOC group (mean 6.18, moderate effect, P = .412). Conclusions: KC was safe and well tolerated with no adverse events. Though efficacy measures were not powered to draw definitive conclusions, trends and clinical assessments suggest that there is a benefit of using KC compared to SOC for breast cancer patients treated with RT, and a larger powered study for efficacy is warranted. Trial Registry: This clinical trial is registered as NCT03374995 titled KeraStat(R) Cream for Radiation Dermatitis.

Comparative Study of Plan Robustness for Breast Radiotherapy: Volumetric Modulated Arc Therapy Plans with Robust Optimization versus Manual Flash Approach

A previous study investigated robustness of manual flash (MF) and robust optimized (RO) volumetric modulated arc therapy plans for breast radiotherapy based on five patients in 2020 and indicated that the RO was more robust than the MF, although the MF is still current standard practice. The purpose of this study was to compare their plan robustness in terms of dose variation to clinical target volume (CTV) and organs at risk (OARs) based on a larger sample size. This was a retrospective study involving 34 female patients. Their plan robustness was evaluated based on measured volume/dose difference between nominal and worst scenarios (ΔV/ΔD) for each CTV and OARs parameter, with a smaller difference representing greater robustness. Paired sample t-test was used to compare their robustness values. All parameters (except CTV ΔD98%) of the RO approach had smaller ΔV/ΔD values than those of the MF. Also, the RO approach had statistically significantly smaller ΔV/ΔD values (p < 0.001-0.012) for all CTV parameters except the CTV ΔV95% and ΔD98% and heart ΔDmean. This study's results confirm that the RO approach was more robust than the MF in general. Although both techniques were able to generate clinically acceptable plans for breast radiotherapy, the RO could potentially improve workflow efficiency due to its simpler planning process.

Near-Surface Dose Correlates With Moist Desquamation and Unplanned Reconstructive Surgery in Patients With Implant-Based Reconstruction Receiving Postmastectomy Radiation Therapy

Purpose

Postmastectomy radiation therapy (PMRT) reduces disease recurrence in appropriately selected patients but may compromise implant-based reconstruction. We investigated whether near-surface dose correlates with radiation-related toxic effects in these patients.

Methods and Materials

Patients receiving PMRT at a single institution from 2016 to 2019 were retrospectively reviewed. Patient demographics and treatment information were collected. Three near-surface structures were retrospectively generated, bound by the chest wall tangent beam as well as the skin surface and the skin-3 mm contour (SR3), skin surface and skin-5 mm contour (SR5), or skin-5 and skin-10 mm contours. Dosimetric analysis of these near-surface contours was performed in 2 Gy intervals. Univariate and multivariate analyses were used to identify predictors of moist desquamation, grade 2+ chest wall pain, use of opiate pain medication, unplanned reconstructive surgery, and implant failure. Logistic regression for each outcome and near-surface contour was performed for receiver-operator area under the curve (AUC) analysis and the Youden J Statistic was used to determine the optimal threshold for each dosimetric parameter.

Results

Of 126 patients reviewed, 109 met the study's eligibility criteria. Median follow-up was 2.3 years. Twenty-five patients (23%) underwent unplanned reconstructive surgery, and 10 (9.2%) experienced implant failure. Among clinical variables, low body mass index and history of smoking predicted unplanned surgery on univariate and multivariate analyses, and moist desquamation predicted grade 2+ chest wall pain. The top dosimetric parameters by AUC for moist desquamation, grade 2+ chest wall pain, use of opiates, unplanned reconstructive surgery, and implant failure were SR5 D10 cc (AUC = 0.701, optimal threshold 57.8 Gy, P < .001), SR3 D10 cc (AUC = 0.600, optimal threshold 56.8 Gy, P = .079), SR5 D10 cc (AUC = 0.642, optimal threshold 57.3 Gy, P = .041), SR3 V44 Gy (AUC = 0.711, optimal threshold 81%, P = .001), and SR3 V44 Gy (AUC = 0.688, optimal threshold 82%, P = .052), respectively.

Conclusions

Near-surface dose correlates with moist desquamation and unplanned reconstructive surgery after PMRT. Further evaluation of prospective optimization of dosimetric parameters related to SR3 and SR5 should be considered.

The effect of chemotherapy and radiotherapy on stem cells and wound healing. Current perspectives and challenges for cell-based therapies

Cancers are part of the group of diseases that carry a high mortality rate. According to World Health Organization in 2020 reported 10 million deaths due to cancers. Treatment of oncological patients is focused on chemotherapeutic agents, radiology, or immunology. Surgical interventions are also an important aspect of treatment. The above methods contribute to saving the patients' health and lives. However, cancer treatment possesses side effects. Commonly observed complications are hair loss, mucositis, nausea, diarrhea, or various skin damage. To improve the quality of medical care for cancer patients, new methods of reducing side effects are sought. Strategies include the use of stem cells (SCs). Due to unlimited proliferation potential and differentiating abilities, SCs are used in the treatment of many disease entities, including wounds. One of the most used types of stem cells supposed adipose-derived mesenchymal stromal cells (AD-MSCs). Clinical trials confirm the application of AD-MSCs in wound healing. Furthermore, in vivo studies considered the utilization of AD-MSCs in radiation injury. The use of stem cells in cancer treatment still involves many questions, such as the impact of treatment on SCs' condition and oncological safety. However, development in regenerative medicine research may contribute to the use of stem cells in personalized medicine, customized for the patient. This could represent a breakthrough step in preventing the side effects of cancer therapies, including chronic wounds.

Radiation-induced skin and heart toxicity in patients with breast cancer treated with adjuvant proton radiotherapy: a comparison with photon radiotherapy

This study aimed to investigate the dose parameters and incidence of radiotherapy (RT)-associated toxicity in patients with left breast cancer (LBC) treated with proton-RT, compared with photon-RT. We collected data from 111 patients with LBC who received adjuvant RT in our department between August 2021 and March 2023. Among these patients, 24 underwent proton-RT and 87 underwent photon-RT. In addition to the dosimetric analysis for organs at risk (OARs), we measured NT-proBNP levels before and after RT. Our data showed that proton-RT improved dose conformity and reduced doses to the heart and lungs and was associated with a lower rate of increased NT-proBNP than did photon-RT. Regarding skin toxicity, the Dmax for 1 c.c. and 10 c.c. and the average dose to the skin-OAR had predictive roles in the risk of developing radiation-induced dermatitis. Although pencil beam proton-RT with skin optimization had a dose similar to that of skin-OAR compared with photon-RT, proton-RT still had a higher rate of radiation dermatitis (29%) than did photon RT (11%). Using mice 16 days after irradiation, we demonstrated that proton-RT induced a greater increase in interleukin 6 and transforming growth factor-β1 levels than did photon-RT. Furthermore, topical steroid ointment reduced the inflammatory response and severity of dermatitis induced by RT. In conclusion, we suggest that proton-RT with skin optimization spares high doses to OARs with acceptable skin toxicity. Furthermore, prophylactic topical steroid treatment may decrease radiation dermatitis by alleviating proton-induced inflammatory responses in vivo.

Topical Iron Chelator Therapy: Current Status and Future Prospects

Systemic iron chelation therapy has long been used for iron overload, providing a role in returning iron levels to proper homeostatic concentrations. Recently, topical iron chelation therapy has emerged as a potential strategy for treating skin damage. This narrative review explores the current status and future prospects of topical iron chelation therapy for treating ultraviolet (UV) and non-UV skin damage, as well as its potential application in wound healing. The review was conducted through a literature search across PubMed, Web of Science, and EMBASE databases, spanning publications from 1990 to 2023. The selection of articles was focused on primary research studies, either experimental or clinical, that explored the implications and formulations of topical iron chelators used alone or in conjunction with another therapeutic agent. The search strategy employed a combination of terms, including "topical iron chelation", "topical deferoxamine", "UV", "wound healing", "skin inflammation", "radiation-induced fibrosis", and "skin cancer". Relevant studies, including methods, intervention strategies, measured outcomes, and findings, are summarized. The review also considered the potential challenges in translating research findings into clinical practice. Results indicate that topical iron chelators, such as deferoxamine, are effective in mitigating UV-induced skin damage, reducing tumorigenesis, and decreasing oxidative damage. In addition, the use of these agents in radiation-induced fibrosis has been shown to significantly increase skin elasticity and reduce dermal fibrosis. Several studies also highlight the use of topical iron chelators in difficult-to-treat chronic wounds, such as diabetic neuropathic ulcers and sickle cell ulcers. In conclusion, topical iron chelation therapy represents a novel and promising approach for skin protection and wound healing. Its potential makes it a promising area of future research.

Prophylactic Use of Mepitel® Film to Prevent Radiation-Induced Moist Desquamation in Cancer Patients

Cancer patients had limited treatment options for decades, such as surgery, chemotherapy, and radiation therapy, alone or combined. However, there have been substantial improvements in recent years with the introduction of stem cell therapy, hormone therapy, anti-angiogenic treatments, immunotherapy, dendritic cell-based targeted therapy, ablation therapy, nanoparticles, natural antioxidants, radionics, chemodynamic therapy, sonodynamic therapy, and ferroptosis-based therapy. Radiation therapy, or radiotherapy, is a cancer treatment that employs high doses of radiation to eliminate cancer cells and shrink tumors. This treatment is effective as a primary, adjuvant, or palliative therapy. It is an essential, efficient, cost-effective intervention crucial for providing proper palliative oncology care. Although cancer treatment modalities such as intensity-modulated radiotherapy have advanced, they still risk harming the skin and surrounding healthy tissue. Radiotherapy may induce clinical toxicity leading to chronic or acute radiation dermatitis, depending on the toxicity caused by the therapy. Radiation dermatitis, whether in its chronic or acute form, can cause skin shedding that may result in the formation of wounds. Such shedding can also lead to non-healing ulcers and radionecrosis. Mepitel® film helps control radiation-induced moist desquamation in cancer patients. Clinical trials on the prophylactic use of Mepitel film on radiation-induced moist desquamation did not show similarities among patients from various countries; however, the film-based method is more beneficial than other methods. This review examines the various types of dressings utilized in managing radiation-induced dermatitis to enhance wound healing effectiveness while avoiding harm to newly developing tissues. Additionally, this review compares the effectiveness of using Mepitel film for treating radiation-induced moist desquamation to other methods.

Performance of auto-planning for VMAT hypofractionated left whole-breast irradiation with simultaneous integrated boost

Retrospective analysis of volumetric modulated arc therapy plans for hypofractionated left whole-breast irradiation with simultaneous integrated boost to assess the performance of the auto-planning (AP) engine. Fifteen treatment plans, produced using manual optimization planning approach (MP) were replanned using (AP) approach. Dose-volume parameters were defined to quantify the quality of concurrent treatment plans assessing target coverage and sparing organs at risk (OARs). The Wilcoxon Signed Rank test was used for statistical comparison of all results obtained from the use of the 2 approaches. Dose coverage for both PTVs, PTV_breast, and PTV_boost, were similar with AP showing slightly significantly better results for the homogeneity index for both PTVs, for D_98% of PTV_breast and D_2% of PTV_boost. AP plans provided a significant reduction of dose for ipsilateral lung and contralateral lung. No significant differences were observed for heart and contralateral breast. A percentage difference of -14.0% was found for the mean dose of left coronary artery between AP plans and MP plans. Despite increase of total MU by 4.3% for AP plans, planning time resulted about half of that of the MP approach. Although PTVs doses were similar between MP and AP plans, AP plans generally spared OARs significantly better than MP plans. Furthermore, the shortest AP treatment plan time approach was attractive with respect to the workload.

Systematic review and meta-analysis on interventions for radiation dermatitis prevention and management: an overview of the methods

Over several decades, research on the prevention and management of acute radiation dermatitis (RD) has continued to emerge, yet there remains no "gold standard" treatment for RD care. Recent guidelines on RD prevention and management were published in 2022 by the Oncodermatology Study Group of the Multinational Association of Supportive Care in Cancer (MASCC). As part of this guideline process, a collaborative effort was undertaken by international RD experts to quantitatively compare commonly studied RD skin interventions through meta-analyses and discern superiority of interventional treatments over another intervention, standard-of-care, or placebo in RD prevention and management. This paper summarizes the materials and methodology used in a set of meta-analysis studies that supplement the 2022 MASCC Clinical Practice Guidelines on RD Prevention and Management.

Mepitel Film for the Prevention of Acute Radiation Dermatitis in Breast Cancer: A Randomized Multicenter Open-Label Phase III Trial

PURPOSE

Radiation dermatitis (RD) is common in patients undergoing breast radiotherapy. Mepitel film (MF) can reduce RD, but the results from two randomized controlled trials are conflicting. We aimed to conduct a confirmatory randomized controlled trial in patients at risk of RD.

METHODS

Patients were randomly assigned to receive MF or standard care (2:1 ratio). Patients with large breasts after lumpectomy (bra size ≥ 36 inches or cup size ≥ C) or after mastectomy were eligible. Stratification factors included surgery type, dose fractionation, and administration of boost/bolus. The primary end point was grade (G) 2 or 3 RD using the Common Terminology Criteria for Adverse Events v5.0. Secondary end points included patient- and clinician-reported outcomes.

RESULTS

Between January 2020 and May 2022, 376 patients were included in the modified intention-to-treat analysis. The incidence of G2 or 3 RD was significantly lower in MF patients compared with standard care (n = 39/251, 15.5%; 95% CI, 11.3 to 20.6% v n = 57/125, 45.6%; 95% CI, 36.7 to 54.8% respectively, odds ratio (OR): 0.20, P < .0001). Benefits of MF remained significant in patients who developed G 3 RD (n = 7, 2.8%; 95% CI, 1.1 to 5.7% v n = 17, 13.6%; 95% CI, 8.1 to 20.9%, OR: 0.19) and moist desquamation (n = 20, 8.0%; 95% CI, 4.9 to 12.0% v n = 24, 19.2%; 95% CI, 12.7 to 27.1%, OR: 0.36). When evaluating the combined patient and health care provider score using Radiation-Induced Skin Reaction Assessment Scale, the MF arm had significantly lower scores (P < .0001). Individual items on the Radiation-Induced Skin Reaction Assessment Scale also favored the MF for both patient- and clinician-reported outcomes. Blistering/peeling, erythema, pigmentation, and edema were significantly reduced in the MF arm. Three patients removed the film prematurely because of rash (n = 2) and excessive pruritus (n = 1).

CONCLUSION

MF significantly reduces RD in patients undergoing breast radiotherapy.

Radiation-induced skin changes after breast or chest wall irradiation in patients with breast cancer and skin of color: a systematic review

INTRODUCTION

The purpose of this study is to systematically review data pertaining to breast cancer and radiation-induced skin reactions in patients with skin of color (SOC), as well as data pertaining to objective measurements of skin pigmentation in the assessment of radiation dermatitis (RD).

METHODS AND MATERIALS

We conducted a systematic review utilizing MEDLINE electronic databases to identify published studies until August 2022. Key inclusion criteria included studies that described RD in breast cancer with data pertaining to skin of color and/or characterization of pigmentation changes after radiation.

RESULTS

We identified 17 prospective cohort studies, 7 cross-sectional studies, 5 retrospective studies and 4 randomized controlled trials. Prospective cohort and retrospective series demonstrate worse RD in African American (AA) patients using subjective physician-graded scales. There is more limited data in patients representing other non-White racial subgroups with SOC. 2 studies utilize patient reported outcomes and 15 studies utilize objective methods to characterize pigmentation change after radiation. There are no prospective and randomized studies that objectively describe pigmentation changes with radiotherapy in SOC.

CONCLUSIONS

AA patients appear to have worse RD outcomes, though this is not uniformly observed across all studies. There are no studies that describe objective measures of RD and include baseline skin pigmentation as a variable, limiting the ability to draw uniform conclusions on the rate and impact of RD in SOC. We highlight the importance of objectively characterizing SOC and pigmentation changes before, during and after radiotherapy to understand the incidence and severity of RD in SOC.

Analysis of risk factors related to acute radiation dermatitis in breast cancer patients during radiotherapy

Aims

To investigate the incidence and influencing factors of acute radiation dermatitis (ARD) induced by radiotherapy in postoperative patients with breast cancer.

Methods and Materials

A retrospective analysis was conducted on 598 patients with breast cancer who received postoperative radiotherapy from November 18, 2014 to September 14, 2019. The radiotherapy technology included two-dimensional radiotherapy, three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and tomotherapy. The occurrence of ARD in patients was then followed up and recorded. The independent risk factors for radiation-induced dermatitis were analyzed by using an orderly logistic regression model.

Results

Of the 598 patients, 431 had mild skin reactions, including pigmentation and dry desquamation (grade 1), 151 developed wet desquamation and tender erythema (grade 2), and 16 had severe skin reactions, including flaky wet scaling and erosion (grade 3). There were no grade 4 skin reactions. The severity of ARD was independent of the following factors: Age, diabetes, allergy, quadrant, pathological type, the clinical stage, the tumor stage, triple-negative breast cancer, ki-67 expression, adjuvant chemotherapy, endocrine therapy, targeted therapy, radiotherapy area, and boost irradiation. However, it was found to be dependent on the body mass index, surgery type, radiotherapy technique, node stage, and the prophylactic use of topical agents.

Conclusions

ARD in response to postoperative radiotherapy in patients with breast cancer is common and mild. Clinicians and patients need to cultivate awareness of the potential risk factors involved and then intervene to alleviate skin reactions and improve the quality of life.

Effect of standard skin care treatments on skin barrier function in X-irradiated hairless mice

Objective

The effectiveness of skin care to radiation dermatitis (RD) on patients who received radiotherapy for cancer has not been clarified. The purpose of this study was to investigate the effect of moisturizers and skin washing on skin barrier function possibly leading to the development of RD using X-ray irradiated hairless mice.

Methods

Nine-week-old hairless mice were irradiated with 10 ​Gy of X-rays, and the skin care group had moisturizers applied or skin washing with soap from the day of irradiation during observations. The condition of the skin was observed to evaluate RD. Skin barrier function was evaluated by measuring skin temperature and transepidermal water loss (TEWL) once every two days until 25 days after X-ray irradiation.

Results

RD was not observed in all groups until 25 days after X-ray irradiation. Skin temperature tended to increase in all groups regardless of irradiation or skin care. However, unlike the control group, the measured value of TEWL in the no skin care group tended to increase in the days after the X-ray irradiation. On the other hand, TEWL was increased in the skin care group compared with the no skin care group a few days after X-ray irradiation. While TEWL was constant in the moisturizer group, the skin washing groups showed an increasing tendency of TEWL and it reached a peak at 13 days after X-ray irradiation.

Conclusions

These results suggested that the decrease in skin barrier function was caused by X-ray irradiation and also that skin washing could contribute to the deterioration of skin barrier function after X-ray irradiation.

A clinical trial to compare a 3D-printed bolus with a conventional bolus with the aim of reducing cardiopulmonary exposure in postmastectomy patients with volumetric modulated arc therapy

BACKGROUND

We compared the dosimetry, application, and acute toxicity of a 3D-printed and a conventional bolus for postmastectomy radiotherapy (PMRT) with volumetric modulated arc therapy (VMAT). Materials and Methods Eligible patients (n = 75) with PMRT breast cancer were randomly selected to receive VMAT with a conventional bolus or a 3D-printed bolus. The primary endpoint was a 10% decrease in the mean heart dose to left-sided breast cancer patients. The secondary endpoint was a 5% decrease in the mean ipsilateral lung dose to all patients. A comparative analysis was carried out of the dosimetry, normal tissue complication probability (NTCP), acute skin toxicity, and radiation pneumonitis.

RESULTS

Compared to a conventional bolus, the mean heart dose in left-sided breast cancer was reduced by an average of 0.8 Gy (5.5 ± 1.3 Gy vs. 4.7 ± 0.8 Gy, p = 0.035) and the mean dose to the ipsilateral lung was also reduced by an average of 0.8 Gy (12.4 ± 1.0 Gy vs. 11.6 ± 0.8 Gy, p < 0.001). The values for V_50Gy of the PTV of the chest wall for the 3D-printed and conventional boluses were 95.4 ± 0.6% and 94.8 ± 0.8% (p = 0.026) and the values for the CI of the entire PTV were 0.83 ± 0.02 and 0.80 ± 0.03 (p < 0.001), respectively. The NTCP for the 3D-printed bolus was also reduced to an average of 0.14% (0.32 ± 0.19% vs. 0.18 ± 0.11%, p = 0.017) for the heart and 0.45% (3.70 ± 0.67% vs. 3.25 ± 0.18%, p < 0.001) for the ipsilateral lung. Grade 2 and Grade 1 radiation pneumonitis were 0.0% versus 7.5% and 14.3% versus 20.0%, respectively (p = 0.184).

CONCLUSIONS

The 3D-printed bolus may reduce cardiopulmonary exposure in postmastectomy patients with volumetric modulated arc therapy.

Risk Factors Related to Acute Radiation Dermatitis in Breast Cancer Patients After Radiotherapy: A Systematic Review and Meta-Analysis

Background

Acute radiation dermatitis (ARD) is the most common acute response after adjuvant radiotherapy in breast cancer patients and negatively affects patients’ quality of life. Some studies have reported several risk factors that can predict breast cancer patients who are at a high risk of ARD. This study aimed to identify patient- and treatment-related risk factors associated with ARD.

Methods

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and WanFang literature databases were searched for studies exploring the risk factors in breast cancer patients. The pooled effect sizes, relative risks (RRs), and 95% CIs were calculated using the random-effects model. Potential heterogeneity and sensitivity analyses by study design, ARD evaluation scale, and regions were also performed.

Results

A total of 38 studies composed of 15,623 breast cancer patients were included in the analysis. Of the seven available patient-related risk factors, four factors were significantly associated with ARD: body mass index (BMI) ≥25 kg/m² (RR = 1.11, 95% CI = 1.06–1.16, I² = 57.1%), large breast volume (RR = 1.02, 95% CI = 1.01–1.03, I² = 93.2%), smoking habits (RR = 1.70, 95% CI = 1.24–2.34, I² = 50.7%), and diabetes (RR = 2.24, 95% CI = 1.53–3.27, I² = 0%). Of the seven treatment-related risk factors, we found that hypofractionated radiotherapy reduced the risk of ARD in patients with breast cancer compared with that in conventional fractionated radiotherapy (RR = 0.28, 95% CI = 0.19–0.43, I² = 84.5%). Sequential boost and bolus use was significantly associated with ARD (boost, RR = 1.91, 95% CI = 1.34–2.72, I² = 92.5%; bolus, RR = 1.94, 95% CI = 1.82–4.76, I² = 23.8%). However, chemotherapy regimen (RR = 1.17, 95% CI = 0.95–1.45, I² = 57.2%), hormone therapy (RR = 1.35, 95% CI = 0.94–1.93, I² = 77.1%), trastuzumab therapy (RR = 1.56, 95% CI = 0.18–1.76, I² = 91.9%), and nodal irradiation (RR = 1.57, 95% CI = 0.98–2.53, I² = 72.5%) were not correlated with ARD. Sensitivity analysis results showed that BMI was consistently associated with ARD, while smoking, breast volume, and boost administration were associated with ARD depending on study design, country of study, and toxicity evaluation scale used. Hypofractionation was consistently shown as protective. The differences between study design, toxicity evaluation scale, and regions might explain a little of the sources of heterogeneity.

Conclusion

The results of this systematic review and meta-analysis indicated that BMI ≥ 25 kg/m² was a significant predictor of ARD and that hypofractionation was consistently protective. Depending on country of study, study design, and toxicity scale used, breast volume, smoking habit, diabetes, and sequential boost and bolus use were also predictive of ARD.

Dosimetric and Clinical Factors Associated with Breast Reconstruction Complications in Patients Receiving Post-Mastectomy Radiation

PURPOSE/OBJECTIVE(S)

Approximately 30% of women who receive post-mastectomy radiation therapy (PMRT) in the setting of breast reconstruction suffer from reconstruction complications. This study aims to assess clinical and dosimetric factors associated with the risk of reconstruction complications after PMRT, with the ultimate goal of identifying a dosimetric constraint that can be utilized clinically to limit this risk.

MATERIALS/METHODS

We retrospectively identified 41 patients who underwent modified radical (MRM) or total mastectomy followed by immediate or delayed reconstruction (autologous or implant-based) and radiation at a single institution from 2014-2020. Reconstruction complications were defined as flap or implant failure, necrosis, capsular contracture, cellulitis/infection, implant rupture, implant malposition, leakage/rupture, unplanned operation, and hematoma/seroma. Clinical and dosimetric variables associated with complications were assessed with univariate analyses.

RESULTS

12 patients (29%) suffered reconstruction complications which led to flap or implant failure in 5 patients. Median time to complication following reconstruction was 8 months. 32% of patients with immediate and 20% with delayed reconstruction suffered a complication, respectively. There were no local failures. Smoking (p=0.02), use of bolus (p=0.03), and V107 > 11% (p=0.03) were associated with increased complication rates. The complication rates were 42% when V107 > 11% versus 12% when V107 < 11%; 58% in smokers versus 17% in nonsmokers; and 42% with bolus versus 7% without.

CONCLUSION

Plan heterogeneity appears to be associated with the risk of reconstruction complications. Pending further validation, V107 < 11% may serve as a reasonable guide to limit this risk. Further consideration should be given to the selective use of bolus in this setting and optimization of clinical factors such as smoking cessation.

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.

The Use of Thermal Imaging in the Evaluation of Temperature Effects of Radiotherapy in Patients after Mastectomy-First Study

The aim of the study was to evaluate the temperature parameter of the breast area in patients undergoing radiotherapy at various intervals. The relationship between temperature changes on the patient’s skin and the time after the end of radiotherapy was studied. Measurements with a thermal imaging camera were performed in a group of twelve volunteers. Six of them were healthy women who did not have thermal asymmetry between the breasts, whereas six were diagnosed with breast cancer and underwent mastectomy due to the advanced stage of the disease. The patients were qualified for radiation therapy. Thermographic examinations were performed before treatment, two months later and then six months after the end of the treatment. Temperature differences between the healthy breasts and the treated areas were assessed. Additionally, the correlation between a patient’s skin temperature changes and the time after the end of radiotherapy was analyzed. The highest skin temperature increase (1.47 °C) was observed 6 months after the end of RT compared to the measurement before treatment. It seems that thermovision may bring a new tool for quantitative analyses of the temperature effects of radiotherapy.

New field-in-field with two reference points method for whole breast radiotherapy: Dosimetric analysis and radiation-induced skin toxicities assessment

The usefulness of the field-in-field with two reference points (FIF w/ 2RP) method, in which the dose reference points are set simultaneously at two positions in the irradiation field and the high-dose range is completely eliminated, was examined in the present study with the aim of decreasing acute skin toxicity in adjuvant breast radiotherapy (RT). A total of 573 patients with breast cancer who underwent postoperative whole breast RT were classified into 178 cases with wedge (W) method, 142 cases with field-in-field without 2 reference points (FIF w/o 2RP) method and 253 cases with FIF w/ 2RP method. Using the FIF w/ 2RP method, the high-dose range was the lowest among the three irradiation methods. The planning target volume (PTV) V105% and the breast PTV for evaluation (BPe) V105% decreased to 0.09 and 0.10%, respectively. The FIF w/ 2RP method vs. the FIF w/o 2RP method had a strong association (η) with PTV V105% (η=0.79; P<0.001) and BPe V105% (η=0.76; P<0.001). The FIF w/ 2RP method had a significant impact on lowering the skin toxicity grade in weeks 3 and 4, and increasing the occurrence of skin toxicity grade 0. The FIF w/ 2RP method vs. the W method had a moderate association with skin toxicity grade at week 3 (η=0.49; P<0.001). Using the FIF w/ 2RP method, the high-dose range V105% of the target decreased to 0%, and skin adverse events were decreased in conjunction. For patients with early-stage breast cancer, particularly patients with relatively small-sized breasts, the FIF w/ 2RP method may be an optimal irradiation method.

Quantitative Changes in Skin Composition Parameters after Radiation Therapy According to Surgery Types Among Patients with Breast Cancer: A Prospective Study

BACKGROUND

In the current study, we sought to evaluate and compare the objective changes in biophysical parameters and patient-reported outcomes following radiation therapy (RT) in patients with breast cancer who underwent breast-conserving surgery (BCS) or modified radical mastectomy (MRM).

MATERIALS AND METHODS

Patients older than 18 years, with stage I to III breast cancer, who were expected to receive RT were recruited between August 2015 and March 2019. Skin hydration, sebum content, pigmentation, and elasticity of the irradiated and unirradiated breast or chest wall were assessed using a noninvasive bioengineering device. Assessments were performed before the initiation of RT (T0); after the 5th (T1), 15th (T2), and 25th (T3) fractions; and 1 (T4) and 3 months (T5) after the completion of RT. Patient-reported outcomes were also evaluated using Radiation Dermatitis Assessment for Breast Cancer 11.

RESULTS

Hydration and sebum levels on the irradiated breast decreased during RT and had not returned to baseline at T5. Erythema on the irradiated breast increased two-fold between T0 and T3, and melanin levels were significantly higher than those at baseline and those of the contralateral unirradiated breast until T5 (106.0 vs. 115.8, P = .03). More than half of the patients continued to report skin color changes, dryness, and pain after RT. The erythema in the irradiated site at T1 was significantly higher in the MRM group than in the BCS group (P for interaction = .04), while there were no significant differences in the changes of the other parameters.

CONCLUSION

RT-induced changes in hydration, sebum, and melanin, and the majority of patient-reported pain, color changes, and dryness, even 3 months after the completion of treatment. There were no remarkable differences in the measurable skin parameters according to the surgery type, with the exception of erythema, which was higher in the MRM group 1 week after the start of RT.

Predictive factors associated with radiation dermatitis in breast cancer

PURPOSE

Radiation dermatitis (RD) is a side effect that frequently arises during radiotherapy (RT) in breast cancer patients. The present study investigates possible predictive factors of RD, as well as the use of skin treatments to manage symptoms.

METHODS

Demographic and treatment characteristics were collected retrospectively, while skin symptoms and treatments were collected prospectively for patients who received adjuvant RT between December 2013 and November 2015. Patients were seen weekly by clinicians throughout treatment, during which a clinician-reported survey was completed on RD symptoms and skin treatments. Possible predictive factors were correlated with skin outcomes through a univariate ordinal logistic regression analysis.

RESULTS

A total of 1093 patients were included in this analysis. Predictive factors for erythema included dose fractionation (p<0.0001), tissue volume irradiated by tangential fields (p = 0.01), and administration of a boost (p = 0.005). High BMI (≥30 kg/m²) (p = 0.0004) and boost (p = 0.02) were predictive of edema. A dose of 50 Gy/25 (p<0.0001) and a high irradiated tissue volume (p = 0.0001) were predictive of desquamation. A dose of 50 Gy/25 (p = 0.0005) and high BMI (p = 0.02) were predictors of pain. Bolus use was the only factor associated with bleeding (p = 0.02). Patients who developed desquamation were likely to receive corticosteroids/antihistamines (p<0.0001), topical antibiotics/antifungals (p<0.001), and dressings (p<0.0001).

CONCLUSION

The findings of this study provide evidence of potential predictors of RD and methods of symptom management based on symptom severity. Prevention of RD is needed among high-risk groups, such as patients with a high BMI or receiving a standard fractionation, boost, or bolus.

Impact of Breast Size on Dosimetric Indices in Proton Versus X-ray Radiotherapy for Breast Cancer

Deep inspiration breath hold (DIBH) radiotherapy is a technique used to manage early stage left-sided breast cancer. This study compared dosimetric indices of patient-specific X-ray versus proton therapy DIBH plans to explore differences in target coverage, radiation doses to organs at risk, and the impact of breast size. Radiotherapy plans of sixteen breast cancer patients previously treated with DIBH radiotherapy were re-planned with hybrid inverse-planned intensity modulated X-ray radiotherapy (h-IMRT) and intensity modulated proton therapy (IMPT). The total prescribed dose was 40.05 Gy in 15 fractions for all cases. Comparisons between the clinical, h-IMRT, and IMPT evaluated doses to target volumes, organs at risk, and correlations between doses and breast size. Although no differences were observed in target volume coverage between techniques, the h-IMRT and IMPT were able to produce more even dose distributions and IMPT delivered significantly less dose to all organs at risk than both X-ray techniques. A moderate negative correlation was observed between breast size and dose to the target in X-ray techniques, but not IMPT. Both h-IMRT and IMPT produced plans with more homogeneous dose distribution than forward-planned IMRT and IMPT achieved significantly lower doses to organs at risk compared to X-ray techniques.

How do patient-reported outcomes compare with clinician assessments? A prospective study of radiation dermatitis in breast cancer

BACKGROUND AND PURPOSE

Breast cancer patients frequently develop radiation dermatitis (RD) when undergoing post-operative radiation therapy (RT). Traditional RD assessment methods measure clinician-reported outcomes (CROs), but patient-reported outcomes (PROs) have gained recent popularity. The purpose of this prospective analysis was to compare PROs with CROs of breast RD.

MATERIALS AND METHODS

Demographic and treatment characteristics were prospectively collected for patients receiving post-operative RT between February 2018 to September 2020. Patients and clinicians completed a skin symptom assessment at baseline, weekly during RT, and at a one- to three-month follow-up visit. Skin treatments used by patients were collected. Concordance between each PRO and CRO was determined using percent concordance and concordance index (C-statistic) by logistic regression analysis.

RESULTS

A total of 777 patients were included in the present study. All skin symptom assessment items were significantly underreported by clinicians in comparison to patients (p < 0.0001), with a low to moderate level of concordance (C-statistic range: 0.58-0.70; percent concordance range: 29-50%). The majority of patients used moisturizing creams as a prophylactic measure (65.1%), as per institutional guidelines.

CONCLUSION

There were significant discrepancies between PROs and CROs when assessing breast RD. CROs alone are insufficient in measuring RD as they fail to capture the impact on patient quality of life. The study findings highlight the need for improved RD symptom assessment and support the development of a new tool with both patient and clinician components.

8-Hydroxy-2'-Deoxyguanosine and 8-Nitroguanine Production and Detection in Blood Serum of Breast Cancer Patients in Response to Postoperative Complementary External Ionizing Irradiation of Normal Tissues

It is widely known that ionizing irradiation is strongly linked to the production of reactive oxygen (ROS) and nitrative species (RNS) through which DNA damage products like 8-hydroxy-2-deoxyguanosine (8-OHdG) and 8-nitroguanine (8-NG) are generated, respectively. In the present study, we aimed to investigate the formation of 8-OHdG and 8-NG upon irradiation and to further explore whether alterations in their concentration levels are related to the administered radiation doses and exposure time. Our research work was conducted in blood serum samples collected from 33 breast cancer patients who received adjuvant radiotherapy. The detection of 8-OHdG and 8-NG was assessed by enzyme-linked immunosorbent assay. Our results suggest that both, 8-OHdG and 8-NG, were formed during the radiation regimen. Significant correlations with radiation dose were also demonstrated by the dose-response curves of 8-OHdG and 8-NG, fitted by logarithmic distribution and polynomial regression, respectively. More precisely, 8-OHdG and 8-NG concentrations (ng/mL) were considerably increased when patients received ionizing radiation up to 30 Gy whereas irradiation over 30 Gy did not induce any further increases. The current study supports a) the production of 8-OHdG and 8-NG during radiotherapy and b) significant correlations between either 8-OHdG or 8-NG levels and radiation doses, indicating a radiation-dose-dependent relationship.

A Retrospective Analysis of Dose Distribution and Toxicity in Patients with Left Breast Cancer Treated with Adjuvant Intensity-Modulated Radiotherapy: Comparison with Three-Dimensional Conformal Radiotherapy

Background

A better understanding of the organs-at-risk (OAR) dose metrics and the related toxicity induced by radiotherapy (RT) for left breast cancer (BC) will improve the quality of life. This study addressed the issue for left-BC patients treated with intensity-modulated radiotherapy (IMRT) compared to three-dimensional conformal radiotherapy (3D-CRT).

Patients and Methods

Between 2012 and 2018, 308 left-BC patients underwent adjuvant RT at our hospital. Before June 2015, 134 patients were treated with 3D-CRT. Thereafter, 174 patients underwent IMRT. The patient’s characteristics in the IMRT group did not significantly different compared to those in the 3D-CRT group.

Results

Among the total study population, the incidence of ≥grade 2 radiation dermatitis (RID) was 17.3%. Higher volumes receiving 105% (≥5.7%) and 107% (≥1%) of prescribed dose and 3D-CRT technique were associated with a higher risk of RID. Regarding lung toxicity, the mean lung dose (≥10.2Gy) and V20 (≥20%) of ipsilateral lung were significantly associated with the incidence of RT-induced pulmonary changes. By dosimetry analysis, IMRT achieved better dose conformity and delivered lower mean doses to heart and ipsilateral lung compared to 3D-CRT. Furthermore, propensity sore and multivariate analysis showed that IMRT technique helped to reduce RT-induced dermatitis and lung toxicity.

Conclusion

Our data suggest that the volume of OAR exposed to higher doses is a predictor of RT-induced toxicity. Adjuvant RT with IMRT technique offered better dose conformity and spared high-dose levels to OARs to reduce radiation-related morbidity for BC patients.

Efficacy of topical Calendula officinalis on prevalence of radiation-induced dermatitis: A randomised controlled trial

OBJECTIVES

A randomised controlled trial was undertaken to compare the efficacy of topical Calendula officinalis (Calendula) versus standard of care (Sorbolene: 10% glycerine in cetomacragol cream) in reducing the prevalence of radiation-induced dermatitis in women undergoing breast cancer radiotherapy.

METHODS

A total of 271 women were screened and 82 were randomised. The primary outcome was prevalence of acute radiation-induced dermatitis (RTOG grade 2+) assessed at multiple skin sites. A chi-squared test was conducted for the primary outcome with a worst-case scenario imputation.

RESULTS

The recruitment target (n = 178) was not achieved. A total of n = 81 participants were analysed (n = 40 Calendula; n = 41 Sorbolene). There was no detectable difference in prevalence of radiation-induced dermatitis grade 2+ between the Calendula (53%) and Sorbolene (62%) groups (primary analysis OR = 0.87, 95% CI: [0.36, 2.09], P = 0.92; covariate adjusted complete case analysis OR 0.40, 95% CI: [0.13, 1.20], P = 0.10).

CONCLUSION

This randomised controlled trial showed no difference between Calendula and standard of care (Sorbolene) for the prevention of radiation-induced dermatitis. However, the study was underpowered (limited recruitment) for the primary comparison.

Quantitative Effect of Bolus on Skin Dose in Postmastectomy Radiation Therapy

BACKGROUND

In postmastectomy radiation therapy (PMRT), some centres prescribe the use of a tissue-equivalent bolus to the skin to reduce the risk of chest wall recurrence. The addition of bolus causes an increase in the skin dose, which may lead to increased risk of radiodermatitis. Radiodermatitis can decrease patients' overall quality of life, bringing into question the benefit of using the bolus. The purpose of this retrospective chart review was to quantify the increase in skin dose associated with the use of bolus in the PMRT setting.

MATERIALS AND METHODS

We evaluated 70 patients who underwent PMRT at our institution during 2012-2018. Two similar treatment plans were generated for each patient: one with bolus and one without. Skin dose-volume histogram values were evaluated, and statistical analysis was performed using MATLAB R2015b.

RESULTS

There was no significant difference in the maximum skin dose within a depth of 5 mm for bolus versus nonbolus plans (P = 0.4). However, within a depth of 3 mm, bolus plans had a maximum skin dose 7% ± 2.5% higher than the nonbolus plans (P < .00001). Mean skin dose within depths of 3 and 5 mm were both significantly higher (P < .00001) for bolus plans. The photon beam energy and chest wall separation showed minimal or no effect on skin dose.

CONCLUSION

Given the differing opinions in the literature regarding the role for bolus in PMRT, there is still uncertainty of the optimal treatment method. This retrospective study demonstrates a 20%-30% reduction in mean skin dose when bolus is not used.

Quantitative Thermal Imaging Biomarkers to Detect Acute Skin Toxicity From Breast Radiation Therapy Using Supervised Machine Learning

PURPOSE

Radiation-induced dermatitis is a common side effect of breast radiation therapy (RT). Current methods to evaluate breast skin toxicity include clinical examination, visual inspection, and patient-reported symptoms. Physiological changes associated with radiation-induced dermatitis, such as inflammation, may also increase body-surface temperature, which can be detected by thermal imaging. Quantitative thermal imaging markers were identified and used in supervised machine learning to develop a predictive model for radiation dermatitis.

METHODS AND MATERIALS

Ninety patients treated for adjuvant whole-breast RT (4250 cGy/f_x = 16) were recruited for the study. Thermal images of the treated breast were taken at 4 intervals: before RT, then weekly at f_x = 5, f_x = 10, and f_x = 15. Parametric thermograms were analyzed and yielded 26 thermal-based features that included surface temperature (°C) and texture parameters obtained from (1) gray-level co-occurrence matrix, (2) gray-level run-length matrix, and (3) neighborhood gray-tone difference matrix. Skin toxicity was evaluated at the end of RT using the Common Terminology Criteria for Adverse Events (CTCAE) guidelines (Ver.5). Binary group classes were labeled according to a CTCAE cut-off score of ≥2, and thermal features obtained at f_x = 5 were used for supervised machine learning to predict skin toxicity. The data set was partitioned for model training, independent testing, and validation. Fifteen patients (∼17% of the whole data set) were randomly selected as an unseen test data set, and 75 patients (∼83% of the whole data set) were used for training and validation of the model. A random forest classifier with leave-1-patient-out cross-validation was employed for modeling single and hybrid parameters. The model performance was reported using receiver operating characteristic analysis on patients from an independent test set.

RESULTS

Thirty-seven patients presented with adverse skin effects, denoted by a CTCAE score ≥2, and had significantly higher local increases in skin temperature, reaching 36.06°C at f_x = 10 (P = .029). However, machine-learning models demonstrated early thermal signals associated with skin toxicity after the fifth RT fraction. The cross-validated model showed high prediction accuracy on the independent test data (test accuracy = 0.87) at f_x = 5 for predicting skin toxicity at the end of RT.

CONCLUSIONS

Early thermal markers after 5 fractions of RT are predictive of radiation-induced skin toxicity in breast RT.

Association between C-reactive protein and radiotherapy-related pain in a tri-racial/ethnic population of breast cancer patients: a prospective cohort study

BACKGROUND

Post-surgery adjuvant radiotherapy (RT) significantly improves clinical outcomes in breast cancer patients; however, some patients develop cancer or treatment-related pain that negatively impacts quality of life. This study examined an inflammatory biomarker, C-reactive protein (CRP), in RT-related pain in breast cancer.

METHODS

During 2008 and 2014, breast cancer patients who underwent RT were prospectively evaluated for pre- and post-RT pain. Pre- and post-RT plasma CRP levels were measured using a highly sensitive CRP ELISA kit. Pain score was assessed as the mean of four pain severity items (i.e., pain at its worst, least, average, and now) from the Brief Pain Inventory. Pain scores of 4-10 were classified as clinically relevant pain. Multivariable logistic regression analyses were applied to ascertain the associations between CRP and RT-related pain.

RESULTS

In 366 breast cancer patients (235 Hispanic whites, 73 black/African Americans, and 58 non-Hispanic whites), 17% and 30% of patients reported pre- and post-RT pain, while 23% of patients had RT-related pain. Both pre- and post-RT pain scores differed significantly by race/ethnicity. In multivariable logistic regression analysis, RT-related pain was significantly associated with elevated pre-RT CRP (≥ 10 mg/L) alone (odds ratio (OR) = 2.44; 95% confidence interval (CI) = 1.02, 5.85); or combined with obesity (OR = 4.73; 95% CI = 1.41, 15.81) after adjustment for age and race/ethnicity.

CONCLUSIONS

This is the first pilot study of CRP in RT-related pain, particularly in obese breast cancer patients. Future larger studies are warranted to validate our findings and help guide RT decision-making processes and targeted interventions.

Daily Fractionation of External Beam Accelerated Partial Breast Irradiation to 40 Gy Is Well Tolerated and Locally Effective

PURPOSE

Most studies examining accelerated partial breast irradiation (APBI) have used twice-daily fractionation. Cosmesis with this approach has produced mixed results, and the optimal fractionation scheme remains unknown. We sought to evaluate the safety and efficacy of APBI with a total dose of 40 Gy in 10 daily fractions.

METHODS AND MATERIALS

Between 2010 and 2014, we prospectively enrolled 106 patients to receive APBI after lumpectomy for invasive or in situ node-negative breast cancer. Radiation was administered via 3-dimensional conformal techniques.

RESULTS

The median age was 62 years (range, 39-85), and all patients underwent APBI per protocol. With a median follow-up of 58 months, we evaluated patient-reported local toxicity and recurrence outcomes. Of 106 patients, 16 (15%) experienced grade ≥2 skin toxicity. The most common significant toxicities were acute cutaneous changes at 4 to 9 weeks after radiation therapy, including grade 2 erythema in 2 patients (1.8%) and skin color changes in 4 patients (3.8%). Only 2 instances of grade 3 toxicity were reported, including 1 patient with acute moist desquamation after radiation therapy and another with fibrosis at 2 years. Planning target volume and breast V₂₀ were significantly predictive of skin/subcutaneous toxicity, with evidence that limiting breast V₂₀ to <45% may improve tolerability. Overall, 3 breast cancer recurrences arose: 1 local recurrence in the original quadrant (3 years after APBI), 1 in a different ipsilateral quadrant (5 years after APBI), and 1 with distant disease 2 years after APBI.

CONCLUSIONS

In an appropriately selected group of patients with early stage breast cancer, APBI to a dose of 40 Gy in 10 daily fractions was well tolerated, with most patients (99%) reporting excellent/good cosmesis. Planning target volume and breast V₂₀ should be carefully constrained to limit local morbidity. Longer follow-up will be needed to establish efficacy and subsequent local recurrence rates.

Skin DVHs predict cutaneous toxicity in Head and Neck Cancer patients treated with Tomotherapy

PURPOSE

To explore the association between planning skin dose-volume data and acute cutaneous toxicity after Radio-chemotherapy for Head and Neck (HN) cancer patients.

METHODS

Seventy HN patients were treated with Helical Tomotherapy (HT) with radical intent (SIB technique: 54/66 Gy to PTV1/PTV2 in 30fr) ± chemotherapy superficial body layer 2 mm thick (SL2) was delineated on planning CT. CTCAE v4.0 acute skin toxicity data were available. Absolute average Dose-Volume Histograms (DVH) of SL2 were calculated for patients with severe (G3) and severe/moderate (G3/G2) skin acute toxicities. Differences against patients with none/mild toxicity (G0/G1) were analyzed to define the most discriminative regions of SL2 DVH; univariable and multivariable logistic analyses were performed on DVH values, CTV volume, age, sex, chemotherapy.

RESULTS

Sixty-one % of patients experienced G2/G3 toxicity (rate of G3 = 19%). Differences in skin DVHs were significant in the range 53-68Gy (p-values: 0.005-0.01). V56/V64 were the most predictive parameters for G2/G3 (OR = 1.12, 95%CI = 1.03-1.21, p = 0.001) and G3 (OR = 1.13, 95%CI = 1.01-1.26, p = 0.027) with best cut-off of 7.7cc and 2.7cc respectively. The logistic model for V56 was well calibrated being both, slope and R2, close to 1. Average V64 were 2.2cc and 6cc for the two groups (G3 vs G0-G2 toxicity); the logistic model for V64 was quite well calibrated, with a slope close to 1 and R2 equal to 0.60.

CONCLUSION

SL2 DVH is associated with the risk of acute skin toxicity. Constraining V64 < 3cc (equivalent to a 4x4cm2 skin surface) should keep the risk of G3 toxicity below or around 10%.

Correlation Between Dosimetric Parameters and Acute Dermatitis of Post-operative Radiotherapy in Breast Cancer Patients

BACKGROUND/AIM

To examine the correlation between dosimetric parameters and acute radiation dermatitis in early breast cancer patients subjected to post-operative radiotherapy.

PATIENTS AND METHODS

The data of 84 patients treated with post-operative radiotherapy were analyzed. The total prescribed dose was 50 Gy in 25 fractions over 5 weeks. Radiation dermatitis was assessed according to Common Terminology Criteria for Adverse Events v4.0. We set organ at risk whole body (from neck to abdomen examined by CT images) also as surrogate skin volume (3 mm thickness).

RESULTS

A total of 28 patients showed radiation dermatitis grade equal or higher than 2 at the 50 Gy time point. These 28 patients were compared to 56 matched pair patients with grade 0-1 radiation dermatitis during the same treatment period. The mean of V5-20 and V40 in patient's whole volume and V40-50 in skin volume were significantly higher in patients who presented with acute radiation dermatitis Grades ≥2 than in the other patients who did not. The statistically most significant difference was observed for V40 for skin volume and V5 for patient whole volume. Rate of acute radiation dermatitis grade ≥2 was significantly higher for patients with V5 (whole body) >1,360 cm³ than those with V5 (whole body) <1,360 cm³ (47% vs. 27%, p=0.0353), as well as for patients with V40 (skin volume) >45 cm³ compared with those with V40 (skin volume) <45 cm³ (50% vs. 18%, p=0.0043).

CONCLUSION

Dosimetric parameters were useful to predict radiation dermatitis grade ≥2. V5 (whole body) 1,360 cm³ and V40 (skin volume) 45 cm³ may be dose volume constrain for radiation dermatitis grade ≥2.

Hypofractionated Whole-Breast Irradiation in Large-Breasted Women-Is There a Dosimetric Predictor for Acute Skin Toxicities?

PURPOSE

Underutilization of hypofractionated whole-breast irradiation (HF-WBI) in large-breasted women may be partially explained by concerns about dose heterogeneity. Although modern planning may mitigate this issue, validated dosimetric guidelines are lacking. Our clinical pathway mandates hypofractionation, guided by institutional dosimetric criteria for plan evaluation. We examined acute radiation dermatitis rates with HF-WBI in large-breasted patients when our guidelines are followed and evaluated factors predictive for dermatitis.

METHODS AND MATERIALS

Patients with whole-breast clinical target volumes (WB-CTV) of ≥1000 cm3 treated with HF-WBI were reviewed. WB-CTV V105, V107, and V110 were assessed. Our guidelines recommend limiting V105 to <10% to 15% and V110 to 0%. The highest grade of acute dermatitis was recorded. Potential clinical and dosimetric predictors of dermatitis were analyzed using logistic regression.

RESULTS

From 2012 to 2017, 505 breasts in 502 patients were treated with HF-WBI. The median WB-CTV was 1261.3 cm3 (interquartile range [IQR], 1115.3-1510.0). Most plans (99%) delivered 42.56 Gy in 16 fractions. A cavity boost of 10 Gy in 4 fractions was delivered in 99% of plans. Electrons were used in 69% of boost plans. Three-dimensional field-in-field technique was used in 68% of plans and inverse-planned intensity modulated radiation therapy in 32%. The median WB-CTV V105 was 9.7% (IQR, 5.6%-13.3%); the median WB-CTV V107 was 0.8% (IQR, 0.0%-2.5%). The WB-CTV V110 was 0% in 97.4% of plans (median, 0.0%; IQR, 0.0%-0.0%). Grade 1, 2, and 3 dermatitis rates were 55.0%, 40.8%, and 3.4%, respectively. On multivariate analysis, age >64 years (P = .016; odds ratio [OR] 4.0; 95% confidence interval [CI], 1.3-12.3), WB-CTV >1500 cm3 (P = .006; OR, 4.3; 95% CI, 1.5-12.3), body mass index ≥34 (P = .044; OR, 3.9; 95% CI, 1.0-14.5), and WB-CTV V105 >10% (P = .011; OR, 5.3; 95% CI, 1.5-19.3) predicted for grade 3 dermatitis.

CONCLUSIONS

With our institutional dosimetric guidelines, grade 3 dermatitis rates with HF-WBI in large-breasted women was <5%. WB-CTV V105 should be optimized to <10% to keep grade 3 dermatitis rates <2%.

Soy Isoflavones Protect Normal Tissues While Enhancing Radiation Responses

Soy isoflavones have demonstrated chemopreventive and anticancer properties in epidemiology and biological studies, in addition to their function as antioxidants in prevention of cardiovascular disease. We have explored the potential of soy isoflavones, as a safe biological approach, to enhance the efficacy of radiotherapy for local tumor control and limit normal tissue damage in solid tumors. This review presents studies investigating the interaction between soy isoflavones and radiation in different malignancies, including prostate cancer, renal cell carcinoma, and nonsmall cell lung cancer. Soy isoflavones were found to be potent sensitizers of cancer cells to radiation causing increased cell killing in vitro in human tumor cell lines and greater tumor inhibition in vivo in preclinical orthotopic murine tumor models. In the course of these studies, radioprotection of normal tissues and organs in the field of radiation was observed both in a clinical trial for prostate cancer and in preclinical models. The mechanisms of radiosensitization and radioprotection mediated by soy isoflavones are discussed and emphasize the role of soy isoflavones in increasing radiation effect on tumor and mitigating inflammatory responses induced by radiation in normal tissues. Soy isoflavones could be used as a safe, nontoxic complementary strategy that simultaneously increases radiation effectiveness on the malignancy while reducing damage in normal tissues in the field of radiation.

Radiation-induced skin reactions: mechanism and treatment

Radiotherapy (RT) is a major treatment for malignant tumors. The latest data show that >70% of patients with malignant tumors need RT at different periods. Skin changes can be experienced by up to 95% of patients who underwent RT. Inflammation and oxidative stress (OS) have been shown to be generally associated with radiation-induced skin reactions (RISRs). Inflammatory response and OS interact and promote each other during RISRs. Severe skin reactions often have a great impact on the progress of RT. The treatment of RISRs is particularly critical because advanced RT technology can also lead to skin reactions. RISRs are classified into acute and chronic reactions. The treatment methods for acute RISRs include steroid treatment, creams, ointments, and hydrocolloid dressings, depending on the reaction grading. Chronic RISRs includes chronic ulcerations, telangiectasias, and fibrosis of the skin, and advanced treatments such as mesenchymal stem cells, hyperbaric oxygen therapy, superoxide dismutase, and low-intensity laser therapy can be considered. Here, we review and summarize the important mechanisms that cause RISRs as well as the standard and advanced treatments for RISRs.

Acute radiodermatitis in modern adjuvant 3D conformal radiotherapy for breast cancer - the impact of dose distribution and patient related factors

Purpose

This study was performed to evaluate skin toxicity during modern three-dimensional conformal radiotherapy (3D-CRT) and to evaluate the importance of dose distribution and patient related factors.

Material and methods

This study comprises 255 patients with breast cancer treated with tangential three-dimensional conformal radiotherapy (3D-CRT) after breast conserving surgery between 03/2012 and 05/2017. The median prescribed dose was 50.4 Gy (range 50–50.4) and 92.2% of the patients received a sequential boost of 10–16 Gy. Adverse skin toxicities (according to CTCAE v. 4.03 and the occurrence of moist desquamations) were assessed at the end of treatment. The dose distribution in the skin (5 mm strip from the patient outline) and in the CTV was evaluated and correlated to the CTCAE scores and the occurrence of moist desquamation.

Results

42.4% of the patients developed grade I, 55.7% grade II and 2% grade III skin toxicities. Moist desquamation was observed in 59 cases (23.1%). Dose distribution within the CTV and skin was homogenous with only small areas receiving 107% of the prescribed dose (median: 0.7 cm³) in the CTV and 105% (median 0.5 cm³) in the skin. On univariate analysis breast size as well as V107%(CTV), V105%(skin) and V80%(skin) correlated significantly (p < 0.05) with the incidence of skin toxicity. On multivariate analysis only V80%(skin) was confirmed as independent risk factor.

Conclusion

Modern tangential multi-field 3D-CRT allows a homogeneous dose distribution with similar skin toxicity as compared to studies performing IMRT. Dose distribution within the skin (V80%) might have a relevant impact on the severity of skin toxicity and the occurrence of moist desquamation.

Comparison of radiation dermatitis between hypofractionated and conventionally fractionated postoperative radiotherapy: objective, longitudinal assessment of skin color

This study aimed to quantitatively compare radiation dermatitis due to hypofractionated (Hypo) and conventionally fractionated (Conv) external-beam radiotherapy in patients who underwent postoperative radiotherapy after breast-conserving surgery. Skin color changes, in terms of L* (brightness, white-black), a* (red-green), and b* (yellow-blue) values, due to external-beam radiotherapy were examined at alternate fractions using an objective method. Twenty-six patients were included in the Hypo group (42.56 Gy/16 fractions) and 46 in the Conv group (50 Gy/25 fractions). Radiotherapy decreased the L* value (darker) and increased the a* value (redder) gradually. These color alterations progressed linearly according to elapsed fractions and were similar between Hypo and Conv per fraction. The Hypo group showed significantly milder alterations in L* and a* values than the Conv group. The maximal dosage was significantly correlated to alterations in L* and a* values. Common Terminology Criteria for Adverse Events v4 assessment did not show a statistically significant difference between the Hypo (Grade 0:1:2 = 2:24:1) and Conv (1:39:6, p = 0.25) groups. The results of our objective analysis revealed that patients undergoing Hypo show milder color alteration than those undergoing Conv and that the maximal dosage is a useful predicator of color alteration.

Relationships among patient characteristics, irradiation treatment planning parameters, and treatment toxicity of acute radiation dermatitis after breast hybrid intensity modulation radiation therapy

To evaluate the relationships among patient characteristics, irradiation treatment planning parameters, and treatment toxicity of acute radiation dermatitis (RD) after breast hybrid intensity modulation radiation therapy (IMRT). The study cohort consisted of 95 breast cancer patients treated with hybrid IMRT. RD grade ≥2 (2⁺) toxicity was defined as clinically significant. Patient characteristics and the irradiation treatment planning parameters were used as the initial candidate factors. Prognostic factors were identified using the least absolute shrinkage and selection operator (LASSO)-based normal tissue complication probability (NTCP) model. A univariate cut-off dose NTCP model was developed to find the dose-volume limitation. Fifty-two (54.7%) of ninety-five patients experienced acute RD grade 2⁺ toxicity. The volume of skin receiving a dose >35 Gy (V₃₅) was the most significant dosimetric predictor associated with RD grade 2⁺ toxicity. The NTCP model parameters for V_35Gy were TV₅₀ = 85.7 mL and γ₅₀ = 0.77, where TV₅₀ was defined as the volume corresponding to a 50% incidence of complications, and γ₅₀ was the normalized slope of the volume-response curve. Additional potential predictive patient characteristics were energy and surgery, but the results were not statistically significant.

To ensure a better quality of life and compliance for breast hybrid IMRT patients, the skin volume receiving a dose >35 Gy should be limited to <85.7 mL to keep the incidence of RD grade 2⁺ toxicities below 50%. To avoid RD toxicity, the volume of skin receiving a dose >35 Gy should follow sparing tolerance and the inherent patient characteristics should be considered.

Clinical Advantage of Chest-wall Post-mastectomy Radiation Therapy Without Bolus

BACKGROUND/AIM

The clinical outcomes of post-mastectomy radiation therapy (PMRT) without bolus remain to be fully examined, so that we evaluated clinical outcomes of PMRT without bolus and to measure the chest-wall dose surface histogram (DSH) parameters.

PATIENTS AND METHODS

Fifty-two patients with breast cancer who received PMRT without bolus were retrospectively analyzed. DSH values of the percentage of maximum dose (D_max) were measured.

RESULTS

All patients completed the treatment; the median follow-up period was 22.1 months. The 2-year overall survival and local control rates were 85% and 95%. Five patients developed grade 2 acute radiation dermatitis, and none developed grade 2 or higher late radiation dermatitis. The median D_max in patients who developed grade 0-1 and grade 2 acute radiation dermatitis was 5,178 and 5,365 cGy (p=0.03).

CONCLUSION

PMRT without bolus resulted in a low frequency of grade 2 or higher radiation dermatitis without increasing locoregional recurrences, and the D_max was the contributing factor for developing acute radiation dermatitis.

Prognostic factors of radiation dermatitis following passive-scattering proton therapy for breast cancer

BACKGROUND

To identify prognostic factors for grade 3 radiation dermatitis following passive-scattering proton therapy for breast cancer.

METHODS

This retrospective study included data on 23 (11 post-mastectomy and 12 post-lumpectomy) breast cancer patients who underwent proton therapy with the passive scattering technique in our institute from 2012 to 2016. Each patient received 50-50.4 cobalt Gy equivalent (CGE) at 1.8 or 2 CGE per daily fraction. Logistic regression analysis was performed to identify prognostic factors for grade 3 skin toxicity. Receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC) were used to evaluate the performance of the models.

RESULTS

43% of the studied patients developed grade 3 radiation dermatitis. The dose-volume histogram (DVH) parameters of V52.5CGE and D10cm³ to skin5mm were correlated with grade 3 radiation dermatitis in both univariate and multivariate logistic regression analyses. Univariate logistic regression analysis suggested that D10cm³ to skin5mm (AUC = 0.69) and V52.5CGE to skin5mm (AUC = 0.70) were prognostic for grade 3 skin toxicity. The models using the combination of D10cm³ to skin5mm or V52.5CGE to skin5mm with breast volume marginally increased the AUC to 0.72 and 0.73, respectively. Models using the combination of D10cm³ to skin5mm or V52.5CGE to skin5mm with history of smoking increased the AUC to 0.75 and 0.83, respectively.

CONCLUSION

In the current study, we identified prognostic factors for grade 3 radiation dermatitis in patients treated with passive-scattering proton therapy for breast cancer. This study provides promising tool for identifying high risk patients for whom treatment plan adjustment could be done to reduce the risk of radiation-induced grade 3 skin toxicity.

Topical Treatment of Skin Injury Inflicted in Mice by X-Ray Irradiation

BACKGROUND/AIMS

There is no treatment, without side effects, efficiently preventing or curing skin burns, caused by radiotherapy. A new experimental topical treatment protocol was assessed in mice receiving orthovoltage X-rays at an equivalent dose to that applied to human breast cancer patients in conventional radiotherapy.

METHODS

SKH-HR2 female hairless mice were irradiated on their dorsum with a total dose of 4,300 cGy during a 1-month period (20 fractions). The treatment group received a combination of 3 topical products, an oil-in-water cream, a gel containing Pinus halepensis bark aqueous extract, and an ointment containing olive oil extract of the marine isopod Ceratothoa oestroides. The positive control group was treated with a conventionally used commercial gel, whereas the negative control group did not receive any topical treatment. Skin alterations were evaluated by macroscopic examinations, measurements of transepidermal water loss (TEWL), melanin content, erythema intensity, hydration, and histopathology assessment.

RESULTS

Sixty days after radiation, TEWL and hydration values were abnormal and elements of acute, chronic, and granulomatous inflammation were present in all cases. The severest damage was detected in the deeper dermis. Treatment showed a comparatively beneficial effect on chronic and granulomatous inflammation while positive control was beneficial on acute inflammation.

CONCLUSION

Skin anti-inflammatory treatment was the most effective but must be applied for several months. Further preclinical studies should be conducted, assimilating a human cancer radiation therapeutic schema with the aim of optimizing skin inflammation treatment.

The incidence of postoperative radiotherapy-induced acute dermatitis in breast cancer and its influencing factors for Chinese women

Purpose

To investigate the incidence of skin acute reaction and its influencing factors in postoperative breast cancer radiotherapy patients.

Methods

One hundred and seventy three cases of breast cancer patients treated with postoperative radiotherapy were consecutively enrolled from June 1, 2016 to July 31, 2017 in our breast cancer center. Irradiation technology includes conformal intensity-modulated radiotherapy and a conventional two-dimensional one with conventional fraction. Any acute radiation dermatitis was recorded and the influencing factors were analyzed at the end of the radiation treatment.

Results

Radiotherapy-induced acute dermatitis in patients with breast-conserving surgery was relatively mild. Among the 173 patients, 33 cases had no obvious changes in the skin (grade 0); 121 cases had grade 1 skin reactions, manifested as local dark erythema and dry peeling; 29 cases had grade 2 skin reactions, characterized by edema, hyperemia, or erosion part; no grade 3 cases of skin reactions were observed. The incidence of grade 0, grade 1, and grade 2 reactions in all patients was 19.1%, 69.9%, and 11.0%, respectively. The severity of skin acute reaction is independent of the tumor sites, molecular subtypes, patients’ age, and irradiation modalities, but it depends on the surgical types, fields treated, and planned total radiation. There is a trend favoring no chemotherapy over chemotherapy, though p-value is 0.074.

Conclusion

Skin acute reaction in postoperative radiotherapy breast cancer patients is generally common but mild, and there are quite a few patients who need interruption or cessation of the radiotherapy process. The patients need to be well informed and made aware that any skin reaction will likely be mild, especially for the breast-conserving patients.

Modifiable risk factors for acute skin toxicity in adjuvant breast radiotherapy: Dosimetric analysis and review of the literature

Acute skin toxicity in adjuvant breast radiation can be reduced with modern radiotherapy (RT) techniques. However, having reviewed the literature, we found no dosimetric constraint for acute skin toxicity that would be applicable to modern RT planning. This study aimed to identify dosimetric factors that are associated with higher rates of acute skin toxicity. A retrospective review was carried out including women who received adjuvant forward-planned intensity-modulated radiotherapy (IMRT) after breast-conserving surgery. Acute skin toxicity grade was prospectively recorded. A total of 131 patients were analyzed. On multivariate analysis, the V105% > 30 cc (p = 0.013) and the use of conventional fractionation (CF) (p = 0.001) were statistically significant for acute skin toxicity. On literature review, current quantitative dosimetric parameters that have shown statistical significance include a V107% > 3 cc in hypofractionation (HF), V107% > 9 cc in CF, treated volume 110% > 5.13%, and V107% > 28.6%. There is little evidence on the predictive value of clinically applicable dosimetric factors in acute skin toxicity. Given the recent improvements in RT planning, we would consider a V107% or a V110% too high a dosimetric value to be useful for the majority of patients. We have shown that a V105% of greater than 30 cc is significantly associated with acute skin toxicity, controlling for other variables. We suggest that this is currently the most useful modifiable parameter available to reduce skin toxicity and is applicable to modern RT planning. We also suggest that consideration be given to hypofractionated schedules to further reduce acute skin toxicity.