Personal characteristics, therapy modalities and individual DNA repair capacity as predictive factors of acute skin toxicity in an unselected cohort of breast cancer patients receiving radiotherapy

Incidence of radiodermatitis and factors associated with its severity in women with breast cancer: a cohort study

BACKGROUND

One of the main adverse reactions of adjuvant radiotherapy for breast cancer is radiodermatitis.

OBJECTIVE

To assess the incidence of radiodermatitis in women with breast cancer, identify factors associated with its severity and determine the time at which this event occurs.

METHODS

Prospective cohort study in 113 women with breast cancer who were evaluated before radiotherapy and at every fifth session until the end of treatment. Logistic regression and Cox proportional regression model were used for the assessment of risk factors; P values < 0.05 were considered significant.

RESULTS

The incidence rate of radiodermatitis was 98.2% and it was demonstrated that for each additional point of the Body Mass Index (BMI), the chance of occurrence of grades II to IV radiodermatitis increases by 14% (OR=1.14 [95% CI 1.04-1.26]; p=0.004) and statin use increases the risk of more severe skin lesions by four-fold (OR=4.27 [95% CI 1.11-16.42]; p=0.035). The exclusive use of hydrogel for skin hydration was an independent factor in delaying the onset of radiodermatitis (HR=0.55 [95% CI 0.36-0.82]; p=0.004).

STUDY LIMITATIONS

The main limitation of this study was its external validity. The identified factors should be considered for services and populations similar to those in this study.

CONCLUSIONS

There was a high incidence of radiodermatitis and its severity was related to higher BMI, statin use; there was a protective effect of hydrogel use.

Topical Ectoin Versus Topical Dexpanthenol for Managing Acute Radiodermatitis Associated With Breast Cancer Radiotherapy: A Randomized Double-Blind Study

Background: Radiodermatitis is a common side effect of breast cancer radiotherapy; however, there is no current consensus regarding an effective standard therapy. Objective: To evaluate the efficacy of topical ectoin versus dexpanthenol in the management of acute radiodermatitis after breast cancer radiotherapy. Methods: Fifty patients randomly used dexpanthenol 5% cream (25 patients), or ectoin 7% cream (25 patients), applied twice daily to the irradiated area during and for 2 weeks after radiotherapy. The study was stratified by the radiotherapy schedule and was double-blind. Radiodermatitis grade, radiation-associated symptoms, and adverse events were assessed weekly during radiotherapy and 2 weeks thereafter. Skin-related quality of life (QOL) scores were measured using the Skindex-16 questionnaire. Results: Both agents were effective in preventing severe radiodermatitis (≥G3). Ectoin had a lower radiodermatitis grade level than dexpanthenol, with a significant difference at week 2 (P = 0.008). Radiation-associated pain (P = 0.003) and itching (P = 0.001) were lower with ectoin than dexpanthenol. Side effects were not significantly different between the 2 treatments (P = 0.107). Ectoin showed less QOL impairment than dexpanthenol. The radiation schedule was an independent predictor for radiodermatitis persistence. Conclusion: Ectoin showed some clinical benefit over dexpanthenol in improving radiation dermatitis and the radiation schedule is a predictor of radiodermatitis persistence.

Longitudinal changes of health-related quality of life over 10 years in breast cancer patients treated with radiotherapy following breast-conserving surgery

PURPOSES

The study intended to (1) assess changes of health-related quality of life (HRQoL) between early treatment-related time points and 10 years post-treatment in a cohort of breast cancer (BC) patients who received radiotherapy (RT), (2) to evaluate differences in HRQoL between long-term BC survivors and unaffected women from the same geographical region and (3) to identify determinants of long-term HRQoL in the survivor cohort.

METHODS

292 BC patients were recruited prior to RT after breast-conserving surgery between 1998 and 2001 in Germany and prospectively followed up for a median of 11.4 years (range 10.3-12.8 years). HRQoL was assessed using EORTC QLQ-C30 at pre-RT (baseline), during RT, 6 weeks after RT, and at the 10-year follow-up. Changes in mean HRQoL scores over time were assessed using linear-mixed models. HRQoL in long-term survivors and controls was compared using Wilcoxon rank-sum test, stratified by age groups. Multivariable linear regression models were used to identify determinants for HRQoL in long-term BC survivors.

RESULTS

Compared to baseline level (mean summary score of 64.9), global health status/quality of life (GHS/QoL) declined during RT (62.4) and improved 6 weeks after RT (69.9) before decreasing to baseline level at the 10-year follow-up (66.7). Most functional domains deteriorated or remained stable at 10 years post-diagnosis compared to post-RT scores, except for role functioning which improved, while dyspnea and diarrhea significantly deteriorated between those two time points. There were no significant differences in long-term GHS/QoL between BC survivors 10 years post-RT and controls for all age groups (p > 0.05). However, deficits in specific HRQoL domains such as emotional burden, sleep problems or fatigue were found to more strongly affect survivors, in particular those younger than 65 years, compared to controls. In the determinant analysis, being overweight was associated with lower GHS/QoL and physical functioning, while living with others was found to be associated with better physical functioning, and decreased dyspnea and pain levels. Certain comorbidities such as depression had a strong association with multiple HRQoL domains, including lower GHS/QoL and functioning as well as a higher level of fatigue, pain, sleep/intestinal problems, and financial difficulties. Side effects such as lymphedema/pain and fibrosis were associated with worse physical and social functioning, respectively.

CONCLUSION

The long-term GHS/QoL remained comparable when compared with the control population while restrictions in certain functional and symptoms domains in long-term BC survivors persisted over 10 years, in particular among younger survivors. Targeted screening to identify cancer survivors at risk for psychosocial/other impairment accounting also for comorbidities and treatment side effects may be warranted in long-term aftercare to address unmet health needs.

Machine-learning prediction model for acute skin toxicity after breast radiation therapy using spectrophotometry

Purpose

Radiation-induced skin toxicity is a common and distressing side effect of breast radiation therapy (RT). We investigated the use of quantitative spectrophotometric markers as input parameters in supervised machine learning models to develop a predictive model for acute radiation toxicity.

Methods and materials

One hundred twenty-nine patients treated for adjuvant whole-breast radiotherapy were evaluated. Two spectrophotometer variables, i.e. the melanin (I_M) and erythema (I_E) indices, were used to quantitatively assess the skin physical changes. Measurements were performed at 4-time intervals: before RT, at the end of RT and 1 and 6 months after the end of RT. Together with clinical covariates, melanin and erythema indices were correlated with skin toxicity, evaluated using the Radiation Therapy Oncology Group (RTOG) guidelines. Binary group classes were labeled according to a RTOG cut-off score of ≥ 2. The patient's dataset was randomly split into a training and testing set used for model development/validation and testing (75%/25% split). A 5-times repeated holdout cross-validation was performed. Three supervised machine learning models, including support vector machine (SVM), classification and regression tree analysis (CART) and logistic regression (LR), were employed for modeling and skin toxicity prediction purposes.

Results

Thirty-four (26.4%) patients presented with adverse skin effects (RTOG ≥2) at the end of treatment. The two spectrophotometric variables at the beginning of RT (I_M,T0 and I_E,T0), together with the volumes of breast (PTV2) and boost surgical cavity (PTV1), the body mass index (BMI) and the dose fractionation scheme (FRAC) were found significantly associated with the RTOG score groups (p<0.05) in univariate analysis. The diagnostic performances measured by the area-under-curve (AUC) were 0.816, 0.734, 0.714, 0.691 and 0.664 for IM, IE, PTV2, PTV1 and BMI, respectively. Classification performances reported precision, recall and F1-values greater than 0.8 for all models. The SVM classifier using the RBF kernel had the best performance, with accuracy, precision, recall and F-score equal to 89.8%, 88.7%, 98.6% and 93.3%, respectively. CART analysis classified patients with I_M,T0 ≥ 99 to be associated with RTOG ≥ 2 toxicity; subsequently, PTV1 and PTV2 played a significant role in increasing the classification rate. The CART model provided a very high diagnostic performance of AUC=0.959.

Conclusions

Spectrophotometry is an objective and reliable tool able to assess radiation induced skin tissue injury. Using a machine learning approach, we were able to predict grade RTOG ≥2 skin toxicity in patients undergoing breast RT. This approach may prove useful for treatment management aiming to improve patient quality of life.

Photobiomodulation therapy in management of cancer therapy-induced side effects: WALT position paper 2022

Disclaimer

This article is based on recommendations from the 12th WALT Congress, Nice, October 3-6, 2018, and a follow-up review of the existing data and the clinical observations of an international multidisciplinary panel of clinicians and researchers with expertise in the area of supportive care in cancer and/or PBM clinical application and dosimetry. This article is informational in nature. As with all clinical materials, this paper should be used with a clear understanding that continued research and practice could result in new insights and recommendations. The review reflects the collective opinion and, as such, does not necessarily represent the opinion of any individual author. In no event shall the authors be liable for any decision made or action taken in reliance on the proposed protocols.

Objective

This position paper reviews the potential prophylactic and therapeutic effects of photobiomodulation (PBM) on side effects of cancer therapy, including chemotherapy (CT), radiation therapy (RT), and hematopoietic stem cell transplantation (HSCT).

Background

There is a considerable body of evidence supporting the efficacy of PBM for preventing oral mucositis (OM) in patients undergoing RT for head and neck cancer (HNC), CT, or HSCT. This could enhance patients’ quality of life, adherence to the prescribed cancer therapy, and treatment outcomes while reducing the cost of cancer care.

Methods

A literature review on PBM effectiveness and dosimetry considerations for managing certain complications of cancer therapy were conducted. A systematic review was conducted when numerous randomized controlled trials were available. Results were presented and discussed at an international consensus meeting at the World Association of photobiomoduLation Therapy (WALT) meeting in 2018 that included world expert oncologists, radiation oncologists, oral oncologists, and oral medicine professionals, physicists, engineers, and oncology researchers. The potential mechanism of action of PBM and evidence of PBM efficacy through reported outcomes for individual indications were assessed.

Results

There is a large body of evidence demonstrating the efficacy of PBM for preventing OM in certain cancer patient populations, as recently outlined by the Multinational Association for Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). Building on these, the WALT group outlines evidence and prescribed PBM treatment parameters for prophylactic and therapeutic use in supportive care for radiodermatitis, dysphagia, xerostomia, dysgeusia, trismus, mucosal and bone necrosis, lymphedema, hand-foot syndrome, alopecia, oral and dermatologic chronic graft-versus-host disease, voice/speech alterations, peripheral neuropathy, and late fibrosis amongst cancer survivors.

Conclusions

There is robust evidence for using PBM to prevent and treat a broad range of complications in cancer care. Specific clinical practice guidelines or evidence-based expert consensus recommendations are provided. These recommendations are aimed at improving the clinical utilization of PBM therapy in supportive cancer care and promoting research in this field. It is anticipated these guidelines will be revised periodically.

The Effectiveness of a Novel Skin Barrier Protectant in the Management of Acute Radiation Dermatitis: A Case Series

OBJECTIVE

Acute radiation dermatitis (ARD) is a frequent adverse effect in patients with cancer undergoing radiotherapy (RT). The aim of this case series is to evaluate the effect of a novel skin barrier protectant in patients with ARD.

METHODS

The skin barrier protectant was used in four patients with different cancer types undergoing RT at two clinical sites. All patients received the standard institutional skincare alongside the novel skin barrier protectant. The skin reactions were evaluated by an RT nurse using the modified version of the Radiation Therapy Oncology Group criteria.

RESULTS

At the final RT session, three of four patients developed erythema with or without dry desquamation. One patient presented only a minor patchy moist wound. Overall, the pain and pruritus due to ARD was low or nonexistent. No adverse events related to the skin barrier protectant were reported.

CONCLUSIONS

This case series demonstrates the beneficial effects and safety of the novel skin barrier protectant in the management of ARD in patients with cancer of different etiologies. These results lay the foundation for future studies with larger, more homogeneous patient populations; a well-defined application scheme; and a stricter study design.

Improving Patients' Life Quality after Radiotherapy Treatment by Predicting Late Toxicities

Personalized treatment and precision medicine have become the new standard of care in oncology and radiotherapy. Because treatment outcomes have considerably improved over the last few years, permanent side-effects are becoming an increasingly significant issue for cancer survivors. Five to ten percent of patients will develop severe late toxicity after radiotherapy. Identifying these patients before treatment start would allow for treatment adaptation to minimize definitive side effects that could impair their long-term quality of life. Over the last decades, several tests and biomarkers have been developed to identify these patients. However, out of these, only the Radiation-Induced Lymphocyte Apoptosis (RILA) assay has been prospectively validated in multi-center cohorts. This test, based on a simple blood draught, has been shown to be correlated with late radiation-induced toxicity in breast, prostate, cervical and head and neck cancer. It could therefore greatly improve decision making in precision radiation oncology. This literature review summarizes the development and bases of this assay, as well as its clinical results and compares its results to the other available assays.

Clinical factors affecting the determination of radiotherapy-induced skin toxicity in breast cancer

Purpose

Radiotherapy is essential for the treatment of breast cancer (BC). However, adverse effects may occur in healthy tissue, during treatment and even after several months. Although it is known that this clinical radiosensitivity is multifactorial, the factors involved are unknown yet. In this study, we evaluated the effect of these factors on the development of radiodermatitis in patients undergoing radiotherapy.

Materials and Methods

Demographic and lifestyle data collected during face-to-face interviews of 122 BC patients and data from clinical records were investigated. Most patients underwent conventional three-dimensional radiotherapy treatment. A total dose of 50 Gy was administered (2 Gy/day), followed by a boost in a tumor bed with a total dose of 18 Gy (2 Gy/day). Radiotoxicity was evaluated weekly using the Radiation Therapy Oncology Group classification system (range, 0 to 4, according to the severity).

Results

In the present study, 75.4% of patients presented acute skin toxic effects with different degrees of severity. In 25% of cases, these effects manifested at the end of the fourth week at a cumulative dose of 40 Gy. The association of grade ≥2 acute skin reactions with body mass index (BMI) and breast size and between grade 3–4 and age was positive compared with controls. However, the role of the other factors could not be confirmed.

Conclusion

Analysis of the factors related to individual radiosensitivity suggests that age, BMI and breast size play an important role in the development of acute skin toxicity during treatment. Particular attention to patients who present these characteristics would help to control treatment effectiveness and therefore optimize their quality of life.

Development and optimisation of a machine-learning prediction model for acute desquamation following breast radiotherapy in the multi-centre REQUITE cohort

Purpose

Some patients with breast cancer treated by surgery and radiation therapy experience clinically significant toxicity, which may adversely affect cosmesis and quality of life. There is a paucity of validated clinical prediction models for radiation toxicity. We used machine learning (ML) algorithms to develop and optimise a clinical prediction model for acute breast desquamation after whole breast external beam radiation therapy in the prospective multicenter REQUITE cohort study.

Methods and Materials

Using demographic and treatment-related features (m = 122) from patients (n = 2058) at 26 centers, we trained 8 ML algorithms with 10-fold cross-validation in a 50:50 random-split data set with class stratification to predict acute breast desquamation. Based on performance in the validation data set, the logistic model tree, random forest, and naïve Bayes models were taken forward to cost-sensitive learning optimisation.

Results

One hundred and ninety-two patients experienced acute desquamation. Resampling and cost-sensitive learning optimisation facilitated an improvement in classification performance. Based on maximising sensitivity (true positives), the “hero” model was the cost-sensitive random forest algorithm with a false-negative: false-positive misclassification penalty of 90:1 containing m = 114 predictive features. Model sensitivity and specificity were 0.77 and 0.66, respectively, with an area under the curve of 0.77 in the validation cohort.

Conclusions

ML algorithms with resampling and cost-sensitive learning generated clinically valid prediction models for acute desquamation using patient demographic and treatment features. Further external validation and inclusion of genomic markers in ML prediction models are worthwhile, to identify patients at increased risk of toxicity who may benefit from supportive intervention or even a change in treatment plan.

Photobiomodulation therapy for the prevention of acute radiation dermatitis in breast cancer patients undergoing hypofractioned whole-breast irradiation (LABRA trial)

OBJECTIVES

To evaluate the efficacy of photobiomodulation therapy in breast cancer patients post-lumpectomy undergoing hypofractionated whole-breast irradiation (HF-WBI) for the prevention and management of acute radiodermatitis (ARD).

MATERIALS AND METHODS

A randomized, multicentric clinical trial (LABRA trial, NCT03924011) was set up at the Limburg Oncology Center, including the Jessa Hospital (Hasselt, BE) and Ziekenhuis Oost-Limburg (Genk, BE). A total of 71 breast cancer patients planned to undergo HF-WBI were randomized to one of the two study arms: the control group (n = 32) or the PBM group (n = 39). The PBM group received the standard institutional skincare combined with PBM (2×/week) during the complete radiotherapy (RT) course. Patients in the control group received the standard skincare combined with placebo treatment (2x/week). Patients' skin reactions were evaluated weekly during the RT treatment by using the modified version of the Radiation Therapy Oncology Group (RTOG) criteria.

RESULTS

At week 3 of RT, one patient presented a grade 2 and one patient a grade 3 skin reaction in the control group, while in the PBM group, all patients still presented grade 1 ARD. At the final RT session 28% of the patients presenting grade 2-3 ARD, while in the PBM group 10% presented grade 2 and no grade 3 ARD. PBM reduced the incidence of severe ARD by 18%. However, the difference was not significant (p = 0.053).

CONCLUSION

Based on the LABRA trial results, PBM seems not able to reduce the incidence of severe ARD in breast cancer patients undergoing HF-WBI. Research in a larger patient population is recommended.

A data science approach for early-stage prediction of Patient's susceptibility to acute side effects of advanced radiotherapy

The prediction by classification of side effects incidence in a given medical treatment is a common challenge in medical research. Machine Learning (ML) methods are widely used in the areas of risk prediction and classification. The primary objective of such algorithms is to use several features to predict dichotomous responses (e.g., disease positive/negative). Similar to statistical inference modelling, ML modelling is subject to the class imbalance problem and is affected by the majority class, increasing the false-negative rate. In this study, seventy-nine ML models were built and evaluated to classify approximately 2000 participants from 26 hospitals in eight different countries into two groups of radiotherapy (RT) side effects incidence based on recorded observations from the international study of RT related toxicity "REQUITE". We also examined the effect of sampling techniques and cost-sensitive learning methods on the models when dealing with class imbalance. The combinations of such techniques used had a significant impact on the classification. They resulted in an improvement in incidence status prediction by shifting classifiers' attention to the minority group. The best classification model for RT acute toxicity prediction was identified based on domain experts' success criteria. The Area Under Receiver Operator Characteristic curve of the models tested with an isolated dataset ranged from 0.50 to 0.77. The scale of improved results is promising and will guide further development of models to predict RT acute toxicities. One model was optimised and found to be beneficial to identify patients who are at risk of developing acute RT early-stage toxicities as a result of undergoing breast RT ensuring relevant treatment interventions can be appropriately targeted. The design of the approach presented in this paper resulted in producing a preclinical-valid prediction model. The study was developed by a multi-disciplinary collaboration of data scientists, medical physicists, oncologists and surgeons in the UK Radiotherapy Machine Learning Network.

Superficial X-ray-induced hyperpigmentation in postoperative keloid radiotherapy: A study of 70 keloids to identify clinical features and risk factors

BACKGROUND

Postoperative radiation is one of the most effective treatments for keloid. Radiation-induced hyperpigmentation is, however, a concern for both patients and dermatologists.

AIMS

To identify clinical features and risk factors of superficial X-ray-induced hyperpigmentation in postoperative keloid radiotherapy.

PATIENTS/METHODS

From November 2019 to November 2020, 70 keloids in 55 patients were treated with superficial X-ray after surgery. Patient data and treatment-related parameters were collected. Follow-up photographs were taken one month after radiotherapy. Three independent dermatologists assessed photographs for pigmentation. The clinical characteristics and severity of pigmentation were summarized. Logistic regression was used to analyze the risk factors associated with occurrence and severity of hyperpigmentation.

RESULTS

The pigmentation was a well-defined rectangular brown macule consistent with the unprotected area that involves normal skin, and 82.9% of keloids displayed pigmentation induced by superficial X-ray at one month after treatment. All keloids of trunk appeared to be mild-to-moderately hyperpigmented (100%); 92.89% of limb keloids displayed mainly severe pigmentation. Keloid location was an independent risk factor for the incidence and severity of pigmentation. Longer incision length was also predictive of increased hyperpigmentation severity.

CONCLUSIONS

Superficial X-ray-induced hyperpigmentation was common and severe in postoperative keloid radiotherapy. The incidence and severity of pigmentation can be predicted by the location and incision length of the keloid.

Tolerability of Breast Radiotherapy Among Carriers of ATM Germline Variants

ATM, a gene that controls repair of DNA double-strand breaks, confers an excess lifetime risk of breast cancer among carriers of germline pathogenic variants (PV). ATM PV homozygotes are particularly sensitive to DNA damage caused by ionizing radiation. Consequently, there is concern that adjuvant radiotherapy (RT) may cause excess morbidity among heterozygous carriers of ATM PV. We evaluated the tolerability of breast RT among carriers of ATM germline variants.

METHODS

Of 167 patients with ATM germline variants presenting to our institution with breast cancer, 91 received RT. Treatment-related toxicity was ascertained from medical records and graded across organ systems. Toxicities grade > 2 were recorded from the end of treatment to last evaluable follow-up and were analyzed according to ATM variant pathogenicity.

RESULTS

Of 91 evaluable carriers of ATM variants, with a median follow-up of 32 months following RT, 25% (n = 23) harbored a PV, whereas 75% (n = 68) harbored a variant of uncertain significance (VUS). Prevalence of grade ≥ 2 toxicity unrelated to post-mastectomy reconstruction among patients with ATM PV was: 32% at the end of treatment (v 34% for VUS carriers), 11% at 1 year of follow-up (v 4% for VUS carriers), and 8% at the last follow-up (v 13% for VUS carriers), consistent with previous studies of RT among unselected populations. No grade 4 or 5 toxicities were observed. ATM variant pathogenicity was not associated with local toxicity, contralateral breast cancer, or secondary malignancy in this limited cohort of patients who received breast RT.

CONCLUSION

We found no evidence of excess RT-associated toxicity among carriers of pathogenic ATM germline variants. Breast-conserving therapy and adjuvant RT may be safely considered among appropriately selected carriers of ATM germline variants.

Evaluating the Effectiveness of a Novel Skin Barrier Protectant in a Patient with Acute Radiodermatitis of the Vulva: A Case Report

OBJECTIVE

To evaluate the use of a novel skin barrier protectant in a patient treated with radiotherapy for vulvar cancer.

METHODS

This case report was conducted in a radiotherapy department with two women undergoing radiotherapy for vulvar carcinoma. A novel skin barrier protectant was evaluated in one patient; the other underwent the institutional standard skin care protocol. Skin reactions and pain were evaluated using the Radiotherapy Oncology Group Criteria.

MAIN RESULTS

The patient who was treated with the skin protectant showed accelerated healing toward the end of radiotherapy, and this was accompanied with a decrease in pain (maximum pain score 6/10). In comparison, the patient treated with the standard skin care protocol had an extended healing process, experienced a higher pain level (maximum pain score 9/10), and required more nursing care.

CONCLUSIONS

This case report is the first to suggest that this novel skin barrier protectant could effectively manage acute radiodermatitis in patients with cancer. This case report hopes to lay the foundation for future randomized controlled trials with a larger and broader patient population.

External Validation of a Predictive Model for Acute Skin Radiation Toxicity in the REQUITE Breast Cohort

Background: Acute skin toxicity is a common and usually transient side-effect of breast radiotherapy although, if sufficiently severe, it can affect breast cosmesis, aftercare costs and the patient's quality-of-life. The aim of this study was to develop predictive models for acute skin toxicity using published risk factors and externally validate the models in patients recruited into the prospective multi-center REQUITE (validating pREdictive models and biomarkers of radiotherapy toxicity to reduce side-effects and improve QUalITy of lifE in cancer survivors) study.

Methods: Patient and treatment-related risk factors significantly associated with acute breast radiation toxicity on multivariate analysis were identified in the literature. These predictors were used to develop risk models for acute erythema and acute desquamation (skin loss) in three Radiogenomics Consortium cohorts of patients treated by breast-conserving surgery and whole breast external beam radiotherapy (n = 2,031). The models were externally validated in the REQUITE breast cancer cohort (n = 2,057).

Results: The final risk model for acute erythema included BMI, breast size, hypo-fractionation, boost, tamoxifen use and smoking status. This model was validated in REQUITE with moderate discrimination (AUC 0.65), calibration and agreement between predicted and observed toxicity (Brier score 0.17). The risk model for acute desquamation, excluding the predictor tamoxifen use, failed to validate in the REQUITE cohort.

Conclusions: While most published prediction research in the field has focused on model development, this study reports successful external validation of a predictive model using clinical risk factors for acute erythema following radiotherapy after breast-conserving surgery. This model retained discriminatory power but will benefit from further re-calibration. A similar model to predict acute desquamation failed to validate in the REQUITE cohort. Future improvements and more accurate predictions are expected through the addition of genetic markers and application of other modeling and machine learning techniques.

Individual Radiosensitivity in Oncological Patients: Linking Adverse Normal Tissue Reactions and Genetic Features

Introduction: Adverse effects of radiotherapy (RT) significantly affect patient's quality of life (QOL). The possibility to identify patient-related factors that are associated with individual radiosensitivity would optimize adjuvant RT treatment, limiting the severity of normal tissue reactions, and improving patient's QOL. In this study, we analyzed the relationships between genetic features and toxicity grading manifested by RT patients looking for possible biomarkers of individual radiosensitivity.

Methods: Early radiation toxicity was evaluated on 143 oncological patients according to the Common Terminology Criteria for Adverse Events (CTCAE). An individual radiosensitivity (IRS) index defining four classes of radiosensitivity (highly radiosensitive, radiosensitive, normal, and radioresistant) was determined by a G₂-chromosomal assay on ex vivo irradiated, patient-derived blood samples. The expression level of 15 radioresponsive genes has been measured by quantitative real-time PCR at 24 h after the first RT fraction, in blood samples of a subset of 57 patients, representing the four IRS classes.

Results: By applying univariate and multivariate statistical analyses, we found that fatigue was significantly associated with IRS index. Interestingly, associations were detected between clinical radiation toxicity and gene expression (ATM, CDKN1A, FDXR, SESN1, XPC, ZMAT3, and BCL2/BAX ratio) and between IRS index and gene expression (BBC3, FDXR, GADD45A, and BCL2/BAX).

Conclusions: In this prospective cohort study we found that associations exist between normal tissue reactions and genetic features in RT-treated patients. Overall, our findings can contribute to the identification of biological markers to predict RT toxicity in normal tissues.

[Predictive assays for responses of tumors and normal tissues in radiation oncology]

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the target volume. Tumor sensitivity to radiotherapy may be particularly inconstant depending on location, histology, somatic genetic parameters and the capacity of the immune system to infiltrate the tumor. In addition, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many radiation treatments. In a same population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists, namely in terms of late side effects that are in principle non-reversible. This review details the different radiobiological approaches that have been developed to better predict the tumor response but also the radiation-induced late effects.

Cutaneous radiation damage: updating a clinically challenging concern

Cutaneous radiation damage, commonly referred to as radiation dermatitis, is a finding of considerable concern. The exposure is often from radiation therapy, a double-edged sword, removing malignant cancer cells and improving the lives of countless patients, yet being locally destructive and potentially premalignant. Among its negative consequences and complications, radiation dermatitis, a potentially severe skin reaction that occurs after the receipt of radiation therapy, presents a clinical challenge today. There are two types of cutaneous radiation dermatitis: acute and chronic. Acute radiation dermatitis manifests within 90 days after the induction of radiation therapy while chronic radiation dermatitis develops beyond 90 days of radiation. There are many risk factors associated with radiation dermatitis which can be characterized as intrinsic, extrinsic, or both. Intrinsic risk factors include concurrent chemotherapy and targeted therapy, connective tissue and skin disorders, genetic and personal factors such as age, sex, smoking habits, and nutritional status. Extrinsic factors are mainly related to the type and dose of the radiation received. Treatment options have been enhanced in the last decade, providing patients with better outcomes and improved quality of life. Such treatments include topical ointments and therapies, oral enzymes, wound dressings and surgical treatments. This article aims to review the current medical understanding of radiation dermatitis, its risk factors, pathophysiology, and treatment options.

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.

Monitoring and Follow-Up of High Radiation Dose Cases in Interventional Radiology

RATIONALE AND OBJECTIVES

To assess the implementation of radiation dose monitoring software, create a process for clinical follow-up and documentation of high-dose cases, and quantify the number of patient reported radiation-induced tissue reactions in fluoroscopically guided interventional radiology (IR) and neuro-interventional radiology (NIR) procedures.

MATERIALS AND METHODS

Web-based radiation dose monitoring software was installed at our institution and a process to flag all procedures with reference point air kerma (K_a,r) > 5000 mGy was implemented. The entrance skin dose was estimated and formal reports generated, allowing for physician-initiated clinical follow-up. To evaluate our process, we reviewed all IR and NIR procedures performed at our hospital over a 1-year period. For all procedures with K_a,r > 5000 mGy, retrospective medical chart review was performed to evaluate for patient reported tissue reactions.

RESULTS

Three thousand five hundred eighty-two procedures were performed over the 1-year period. The software successfully transferred dose data on 3363 (93.9%) procedures. One thousand three hundred ninety-three (368 IR and 1025 NIR) procedures were further analyzed after excluding 2189 IR procedures with K_a,r < 2000 mGy. Ten of 368 (2.7%) IR and 52 of 1025 (5.1%) NIR procedures exceeded estimated skin doses of 5000 mGy. All 10 IR cases were abdominal/pelvic trauma angiograms with/without embolization; there were no reported tissue reactions. Of 52 NIR cases, 49 were interventions and 3 were diagnostic angiograms. Five of 49 (10.2%) NIR patients reported skin/hair injuries, all of which were temporary.

CONCLUSION

Software monitoring and documentation of radiation dose in interventional procedures can be successfully implemented. Radiation-induced tissue reactions are relatively uncommon.

Prevention and treatment of radiation-induced acute dermatitis in head and neck cancer patients: a systematic review

Acute dermatitis is the most common radio-induced side effect during treatment for head and neck cancer. The use of a wide variety of agents is reported to handle skin toxicity. Our aim was to review the literature and synthesize current available evidence. A comprehensive search was performed on multiple electronic databases until February 2017 and a systematic approach was carried out according to PRISMA guidelines. A total of 17 papers (950 patients on the whole) met the inclusion/exclusion criteria, with 12 randomized controlled trials and five nonrandomized observational and prospective studies. Generally speaking, there was no strong evidence to support the superiority of any specific intervention neither in prevention nor in therapeutic settings. Well-designed randomized studies including quality of life measurements are needed.

The Patient Perspective on Radiogenomics Testing for Breast Radiation Toxicity

Aims

In the field of radiogenomics, several potential predictive genetic markers have been identified that are associated with individual susceptibility to radiation toxicity. Predictive models of radiation toxicity incorporating radiogenomics and other biomarkers are being developed as part of the ongoing multicentre REQUITE trial. The purpose of this study was to explore patient attitudes towards future predictive radiogenomics testing for breast radiation toxicity.

Patients and methods

Twenty-one semi-structured interviews were conducted with breast cancer patients taking part in the REQUITE study at one centre. We used inductive thematic analysis to generate common themes.

Results

We identified three emerging themes describing attitudes and feelings towards a predictive radiogenomics test for breast radiation toxicity: theme 1 – willingness to undergo a test (subthemes – information, trusted expert); theme 2 – implications of a test (subthemes – preparation and planning, anxiety without recourse); theme 3 – impact on treatment decision-making (subthemes – prioritising cancer cure, preserving breast integrity, patient preferences).

Conclusions

Results from the present study indicate that patients support and have confidence in the validity of a radiogenomics test for breast radiation toxicity, but they would prefer the result be provided to healthcare professionals. Except in cases of significant chronic symptoms and pain or significant end-organ damage, participants in this study rarely felt that advance knowledge of their personal risk of breast radiation toxicity would influence their treatment decision-making. These findings provide a number of insights that will allow us to anticipate how patients are likely to engage with predictive radiogenomics testing in the future.

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Patients’ views and opinions on predictive radiogenomics testing were investigated.

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Semi-structured interviews with breast cancer patients enrolled in the prospective REQUITE cohort.

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Participants would prefer the test result to be provided to healthcare professionals rather than directly to patients.

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Participants rarely felt that advance knowledge of their risk of radiation toxicity would influence their treatment decision.

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Participants were prepared to consider a treatment change, if predicted to have significant chronic side-effects or end-organ damage.

Association between weight gain during adjuvant chemotherapy for early-stage breast cancer and survival outcomes

Obese and overweight women have an increased risk of breast cancer and worse outcomes at the time of diagnosis. Women tend to gain weight after breast cancer diagnosis and during chemotherapy for early‐stage disease, which may in turn increase risk for worse outcomes. We examined if weight gained during adjuvant chemotherapy was associated with worse survival outcomes. We queried our database for data on patients who received adjuvant third‐generation chemotherapy for early‐stage breast cancer. Univariate and multivariate analyses by Cox regression were performed for survival outcomes across three categories according to BMI variation from start to end of chemotherapy: >0.5 kg/m² loss or gain and stable BMI (±0.5 kg/m²). We included 1998 patients in this study. Women over 50 years old and postmenopausal were more likely to lose weight during adjuvant chemotherapy, whereas women under 30 years old gained more weight (P < 0.001). At 1 year postchemotherapy, patients tended to return to their original weight (ρ = −0.3, P < 0.001). On multivariate analysis, BMI increase of >0.5 kg/m² compared to maintaining BMI was marginally associated with increased locoregional recurrence risk (HR: 2.53; 95% CI, 1.18–5.45; P = 0.017), adjusting for grade, stage, and radiation delivery. Weight variation during adjuvant chemotherapy for early‐stage breast cancer may occur as both weight gain and weight loss in a balanced manner. Furthermore, this variation seems to be transient in nature and does not appear to significantly influence recurrence rates and overall survival.

Acute radiation dermatitis in breast cancer patients: challenges and solutions

Nearly all women who receive radiotherapy (RT) for breast cancer experience some degree of radiation dermatitis. However, evidence describing the appropriate management of radiation dermatitis is often lacking or contradictory. Here, we summarize the available literature regarding radiation dermatitis causes, the presentation and timing of symptoms, methods for dermatitis assessment and prevention, and review evidence-based management strategies.

Breast reconstruction following nipple-sparing mastectomy: clinical outcomes and risk factors related complications

BACKGROUND

The aim of this study was to investigate clinical outcomes and risk factors related complications in patients who had undergone nipple-sparing mastectomy (NSM) followed by implant-based or autologous reconstruction.

METHODS

Between 2004-2014 a single-institution retrospective review was collected on NSMs reconstruction. Patient demographics, comorbidities, breast morphological factors, type and timing of radiotherapy, type of incision, reconstruction type and timing, implant volume and complications were collected.

RESULTS

A total of 288 patients had undergone 369 NSMs, 81 (28.1%) of which were bilateral while 207 (71.9%) unilateral. One-hundred mastectomies were performed for prophylactic purposes whereas 269 were therapeutics. Thirteen (4.5%) patients were active smokers, while 2 (0.7%) were diabetics. Fifty-five breasts (14.9%) were previously irradiated and average time elapsed between radiotherapy and NSM was 9-year, (range, 5-15 yrs). Total complication rate was 13.5% at mean follow-up of 47.98 months (range, 6-114 months). Partial-thickness and full-thickness mastectomy skin flap and NAC necrosis occurred in 39 (78%) and in 10 (20%) breasts, respectively. Previous radiotherapy and implant volume were significant predictors of complications (OR: 10.14, 95% CI: 3.99-27.01; OR × 100 g: 3.13, 95% CI: 1.64-6.33). Overall mastectomy type incision was not predictive of complications (p = .426). No association was observed between radiotherapy and mastectomy type access (p = .349).

CONCLUSIONS

From our experience NSM followed by implant-based and autologous reconstruction had a relative high rate of complications comparable to previous reports. Despite this, it should be carefully offered to patients in whom potential risk factors are identified.

In vivo skin dose measurement using MOSkin detectors in tangential breast radiotherapy

The purpose of this study is to measure patient skin dose in tangential breast radiotherapy. Treatment planning dose calculation algorithm such as Pencil Beam Convolution (PBC) and in vivo dosimetry techniques such as radiochromic film can be used to accurately monitor radiation doses at tissue depths, but they are inaccurate for skin dose measurement. A MOSFET-based (MOSkin) detector was used to measure skin dose in this study. Tangential breast radiotherapies ("bolus" and "no bolus") were simulated on an anthropomorphic phantom and the skin doses were measured. Skin doses were also measured in 13 patients undergoing each of the techniques. In the patient study, the EBT2 measurements and PBC calculation tended to over-estimate the skin dose compared with the MOSkin detector (p<0.05) in the "no bolus radiotherapy". No significant differences were observed in the "bolus radiotherapy" (p>0.05). The results from patients were similar to that of the phantom study. This shows that the EBT2 measurement and PBC calculation, while able to predict accurate doses at tissue depths, are inaccurate in predicting doses at build-up regions. The clinical application of the MOSkin detectors showed that the average total skin doses received by patients were 1662±129cGy (medial) and 1893±199cGy (lateral) during "no bolus radiotherapy". The average total skin doses were 4030±72cGy (medial) and 4004±91cGy (lateral) for "bolus radiotherapy". In some cases, patient skin doses were shown to exceed the dose toxicity level for skin erythema. Hence, a suitable device for in vivo dosimetry is necessary to accurately determine skin dose.

Radiation dermatitis: an overview

Radiation therapy has been a commonly employed modality for a variety of ailments, including cancer. Patients undergoing radiation often experience acute and/or chronic skin changes that can be detrimental to their quality of life. Many topical agents and specialized wound dressings are being used for the prevention and management of radiation-induced skin changes. However, no single therapeutic option has been found to be consistently effective.

Elevated ARG1 expression in primary monocytes-derived macrophages as a predictor of radiation-induced acute skin toxicities in early breast cancer patients

Radiation therapy (RT) the front-line treatment after surgery for early breast cancer patients is associated with acute skin toxicities in at least 40% of treated patients. Monocyte-derived macrophages are polarized into functionally distinct (M1 or M2) activated phenotypes at injury sites by specific systemic cytokines known to play a key role in the transition between damage and repair in irradiated tissues. The role of M1 and M2 macrophages in RT-induced acute skin toxicities remains to be defined. We investigated the potential value of M1 and M2 macrophages as predictive factors of RT-induced skin toxicities in early breast cancer patients treated with adjuvant RT after lumpectomy. Blood samples collected from patients enrolled in a prospective clinical study (n = 49) were analyzed at baseline and after the first delivered 2Gy RT dose. We designed an ex vivo culture system to differentiate patient blood monocytes into macrophages and treated them with M1 or M2-inducing cytokines before quantitative analysis of their "M1/M2" activation markers, iNOS, Arg1, and TGFß1. Statistical analysis was performed to correlate experimental data to clinical assessment of acute skin toxicity using Common Toxicity Criteria (CTC) grade for objective evaluation of skin reactions. Increased ARG1 mRNA significantly correlated with higher grades of erythema, moist desquamation, and CTC grade. Multivariate analysis revealed that increased ARG1 expression in macrophages after a single RT dose was an independent prognostic factor of erythema (p = 0 .032), moist desquamation (p = 0 .027), and CTC grade (p = 0 .056). Interestingly, multivariate analysis of ARG1 mRNA expression in macrophages stimulated with IL-4 also revealed independent prognostic value for predicting acute RT-induced toxicity factors, erythema (p = 0 .069), moist desquamation (p = 0 .037), and CTC grade (p = 0 .046). To conclude, our findings underline for the first time the biological significance of increased ARG1 mRNA levels as an early independent predictive biomarker of RT-induced acute skin toxicities.

Polymorphic Variants in Oxidative Stress Genes and Acute Toxicity in Breast Cancer Patients Receiving Radiotherapy

Purpose

Reactive oxygen species (ROS) are generated as an indirect product of radiation therapy (RT). Genetic variation in genes related to ROS metabolism may influence the level of RT-induced adverse effects. We evaluated the potential association of single nucleotide polymorphism (SNP)–related response to radiotherapy injury in breast cancer patients undergoing RT.

Materials and Methods

Eighty patients receiving conventional RT were included. Acute effects were evaluated according to the Radiation Therapy Oncology Group (RTOG) scores. DNA was extracted from blood and buccal swab samples. SNPs were genotyped for GSTP1, GSTA1, SOD2, and NOS3 genes by polymerase chain reaction–based restriction fragment length polymorphism. Univariate analysis (odds ratios [ORs] and 95% confidence interval [CI]) and principal component analysis were used for correlation of SNPs and factors related to risk of developing ≥ grade 2 acute effects.

Results

Sixty-five patients (81.2%) showed side effects, 32 (40%) presented moderate to severe acute skin toxicity, and 33 (41.2%) manifested minimal acute skin reactions by the end of treatment. In both univariate and multivariate analyses, nominally significant associations were found among body mass index (OR, 3.14; 95% CI, 8.5338 to 1.1274; p=0.022), breast size (OR, 5.11; 95% CI, 17.04 to 1.54; p=0.004), and grade ≥ 2 acute radiation skin toxicity. A significant association was also observed between NOS3 G894T polymorphism (OR, 9.8; 95% CI, 211.6 to 0.45; p=0.041) and grade ≥ 2 acute radiation skin toxicity in patients with neo-adjuvant chemotherapy treatment.

Conclusion

The analysis of the factors involved in individual radiosensitivity contributed to the understanding of the mechanisms underlying this trait.

Correlation between anthropometric parameters and acute skin toxicity in breast cancer radiotherapy patients: a pilot assessment study

OBJECTIVE

The objective of the present study was to identify acute skin toxicity risk factors linked to the anthropometric characteristics of patients with breast cancer treated with radiation therapy.

METHODS

Consecutive patients with breast cancer were enrolled after breast-conserving surgery and before radiotherapy course. Acute skin toxicity was assessed weekly during the 7 weeks of radiotherapy with the International Classification from National Cancer Institute. Grade 2 defined acute skin toxicity. Patient characteristics and anthropometric measurements were collected.

RESULTS

54 patients were enrolled in 2013. Eight patients (14.8%) had grade ≥2 toxicity. The average weight and chest size were 65.5 kg and 93.6 cm, respectively. Bra cup size is significantly associated with a risk of grade 2 dermatitis [odds ratio (OR) 3.46, 95% confidence interval (CI) (1.29-11.92), p = 0.02]. Anthropometric breast fat mass measurements, such as thickness of left [OR 2.72, 95% CI (1.08-8.26), p = 0.04] and right [OR 2.45, 95% CI (0.99-7.27), p = 0.05] axillary fat, are correlated with an increased risk. Distance between the pectoral muscle and nipple is a reproducible measurement of breast size and is associated with acute skin toxicity with significant tendency (OR = 2.21, 95% CI (0.97-5.98), p = 0.07).

CONCLUSION

Breast size and its different anthropometric measurements (thickness of left and right axillary fat, nipple-to-pectoral muscle distance) are correlated with the risk of skin toxicity.

ADVANCES IN KNOWLEDGE

The present article analyses several characteristics and anthropomorphic measurements of breast in order to assess breast size. A standardized and reproducible protocol to measure breast volume is described.

Predicting radiotherapy-related clinical toxicities in cancer: a literature review

Assessment of patients receiving radiotherapy for cancer is essential, with the ability to identify those who may be more likely to experience radiotherapy-related side effects noted as an important issue for nurses. Body mass, age, and radiation dose may be predictive factors for the development of such side effects. This review considers these factors and how nurses can use this evidence to inform their care, with results indicating that the dose of radiation, the site treated, and body mass index are predictive of toxicities that may develop. Increased awareness of these predictive factors will aid nurses in identifying patients at greater risk of developing radiation-related side effects. This will assist in guiding nursing interventions, as well as enabling the individualization of patient education, by placing greater emphasis on preventive measures for patients who are more vulnerable to the development of radiation-related toxicities.

A Review of the Use of Topical Calendula in the Prevention and Treatment of Radiotherapy-Induced Skin Reactions

Calendula is a topical agent derived from a plant of the marigold family Calendula Officinalis. Containing numerous polyphenolic antioxidants, calendula has been studied in both the laboratory and clinical setting for the use in treating and preventing radiation induced skin toxicity. Despite strong evidence in the laboratory supporting calendula's mechanism of action in preventing radiation induced skin toxicity, clinical studies have demonstrated mixed results. In light of the controversy surrounding the efficacy of calendula in treating and preventing radiodermatitis, the topic warrants further discussion.

Genetic risk score and acute skin toxicity after breast radiation therapy

Genetic predisposition has been shown to affect the severity of skin complications in breast cancer patients after radiotherapy. Limited data exist regarding the use of a genetic risk score (GRS) for predicting risk of tissue radiosensitivity. We evaluated the impact of different single-nucleotide polymorphisms (SNPs) in genes related to DNA repair mechanisms and oxidative stress response combined in a GRS on acute adverse effects induced by breast radiation therapy (RT). Skin toxicity was scored according to the Radiation Therapy Oncology Group (RTOG) criteria in 59 breast cancer patients who received RT. After genotyping, a multilocus GRS was constructed by summing the number of risk alleles. The hazard ratio (HR) for GSTM1 was 2.4 (95% confidence intervals [CI]=1.1-5.3, p=0.04). The other polymorphisms were associated to an increased adverse radiosensitivity, although they did not reach statistical significance. GRS predicted roughly 40% risk for acute skin toxicity per risk allele (HR 1.37, 95% CI=1.1-1.76, p<0.01). Patients in the top tertile had a fivefold higher risk of skin reaction (HR 5.1, 95% CI=1.2-22.8, p=0.03). Our findings demonstrate that the joint effect of SNPs from oxidative stress and DNA damage repair genes may be a promising approach to identify patients with a high risk of skin reaction after breast RT.

Protecting the radiation-damaged skin from friction: a mini review

Radiation-induced skin reactions are an unavoidable side effect of external beam radiation therapy, particularly in areas prone to friction and excess moisture such as the axilla, head and neck region, perineum and skin folds. Clinical studies investigating interventions for preventing or managing these reactions have largely focussed on formulations with moisturising, anti-inflammatory, anti-microbial and wound healing properties. However, none of these interventions has emerged as a consistent candidate for best practice. Much less emphasis has been placed on evaluating ways to protect the radiation-damaged skin from friction and excess moisture. This mini review analyses the clinical evidence for barrier products that form a protective layer by adhering very closely to the skin folds and do not cause further trauma to the radiation-damaged skin upon removal. A database search identified only two types of barrier products that fitted these criteria and these were tested in two case series and six controlled clinical trials. Friction protection was most effective when the interventions were used from the start of treatment and continued for several weeks after completion of treatment. Soft silicone dressings (Mepilex Lite and Mepitel Film) and Cavilon No Sting Barrier Film, but not Cavilon Moisturizing Barrier Cream, decreased skin reaction severity, most likely due to differences in formulation and skin build-up properties. It seems that prophylactic use of friction protection of areas at risk could be a worthwhile addition to routine care of radiation-damaged skin.

Radiation-induced complications in endovascular neurosurgery: incidence of skin effects and the feasibility of estimating risk of future tumor formation

BACKGROUND

The incidence of radiation-induced complications is increasingly part of the informed consent process for patients undergoing neuroendovascular procedures. Data guiding these discussions in the era of modern radiation-minimizing equipment is lacking.

OBJECTIVE

To quantify the rates of skin and hair effects at a modern high-volume neurovascular center, and to assess the feasibility of accurately quantifying the risk of future central nervous system (CNS) tumor formation.

METHODS

We reviewed a prospectively collected database of endovascular procedures performed at our institution in 2008. The entrance skin dose and brain dose were calculated. Patients receiving skin doses >2 Gy were contacted to inquire about skin and hair changes. We reviewed several recent publications from leading radiation physics bodies to evaluate the feasibility of accurately predicting future cancer risk from neurointerventional procedures.

RESULTS

Seven hundred two procedures were included in the study. Of the patients receiving >2 Gy, 39.6% reported subacute skin or hair changes following their procedure, of which 30% were permanent. Increasing skin dose was significantly associated with permanent hair loss. We found substantial methodological difficulties in attempting to model the risk of future CNS tumor formation given the gaps in our current understanding of the brain's susceptibility to low-dose ionizing radiation.

CONCLUSION

Radiation exposures exceeding 2 Gy are common in interventional neuroradiology despite modern radiation-minimizing technology. The incidence of side effects approaches 40%, although the majority is self-limiting. Gaps in current models of brain tumor formation after exposure to radiation preclude accurately quantifying the risk of future CNS tumor formation.

[Intrinsic radiosensitivity: predictive assays that will change daily practice]

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the targeted volume. Nevertheless, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many radiation treatments. In a same population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists, namely in terms of late side effects that are in principle non-reversible. This review details the different radiobiological approaches that have been developed to better understand the mechanisms of radiation-induced late effects. We also present the possibilities of clinical use of predictive assays in the close future.