Incidence and correlates of radiation dermatitis in children and adolescents receiving radiation therapy for the treatment of paediatric sarcomas

Effect of Race and Ethnicity on Risk of Radiotherapy Toxicity and Implications for Radiogenomics

AIMS

Patient factors affect the risk of radiotherapy toxicity, but many are poorly defined. Studies have shown that race affects cancer incidence, survival, drug response, molecular pathways and epigenetics. Effects on radiosensitivity and radiotherapy toxicity are not well studied. The aim of the present study was to identify the effects of race and ethnicity on the risk of radiotherapy toxicity.

MATERIALS AND METHODS

A systematic review was carried out of PubMed, Ovid Medline and Ovid Embase with no year limit. PRISMA 2020 guidelines were followed. Two independent assessors reviewed papers.

RESULTS

Of 607 papers screened, 46 fulfilled the inclusion criteria. Papers were published between 1996 and 2021 and involved 30-28,354 individuals (median 433). Most involved patients with prostate (33%), breast (26%) and lung (9%) cancer. Both early and late toxicities were studied. Some studies reported a higher risk of toxicity in White men with prostate cancer compared with other races and ethnicities. For breast cancer patients, some reported an increased risk of toxicity in White women compared with other race and ethnic groups. In general, it was difficult to draw conclusions due to insufficient reporting and analysis of race and ethnicity in published literature.

CONCLUSIONS

Reporting of race and ethnicity in radiotherapy studies must be harmonised and improved and frameworks are needed to improve the quality of reporting. Further research is needed to understand how ancestral heritage might affect radiosensitivity and risk of radiotherapy toxicity.

H&N and Skin (HNS) GEC-ESTRO Working Group critical review of recommendations regarding prescription depth, bolus thickness and maximum dose in skin superficial brachytherapy with flaps and customized moulds

The aim of this publication is the assessment of the existing guidelines for non-melanoma skin cancer (NMSC) superficial brachytherapy (BT) and make a critical review based on the existing literature about the maximum dose prescription depth, bolus thickness and maximum skin surface dose (D_max) of the published clinical practice. A systematic review of NMSC superficial BT published articles was carried out by the GEC-ESTRO Head & Neck and Skin (HNS) Working Group (WG). 10 members and 2 external reviewers compared the published clinical procedures with the recommendations in the current guidelines and examined the grade of evidence. Our review verified that there is a large variation among centres with regards to clinical practice in superficial BT and identified studies where published parameters such as maximum dose prescription depth, bolus thickness and D_max exceed the constraints recommended in the guidelines, while showing excellent results in terms of local control, toxicity and cosmesis. This review confirmed that current recommendations on skin superficial BT do not include published experience on tumours treated with superficial BT that require dose prescription depth beyond the recommended 5mm under the skin surface and that the existing literature does not provide sufficient evidence to relate dosimetry of superficial BT to patient reported outcome measures. The GEC-ESTRO HNS WG considers acceptable to prescribe superficial BT dose at a depth above 5mm beyond the skin surface, and modify the bolus thickness to optimize the treatment plan and adjust the acceptable maximum dose on the skin surface, all pending clinical situation.

Supportive care for toxicities in children undergoing radiation therapy

Radiation therapy (RT) is an integral part of the management of many pediatric tumors; however, it is associated with both acute and permanent adverse events that can significantly impact a child's quality of life, lead to treatment delays, and potentially affect outcomes of cancer therapy. Prevention, early detection, and optimal management of these adverse effects will help reduce their impact on the patients' quality of life and overall well-being. Unfortunately, there has not been a coordinated effort to study the etiology, evaluate risk factors, and explore novel treatments for these conditions. Studies of supportive care for children undergoing RT are often small and uncontrolled. This review will focus on the impact of irradiation on the different organ systems and their current management. Further studies are required to improve our understanding of the contributing factors and explore novel treatment options for these adverse effects and to enable children and their families to better cope with some of the unavoidable toxicities following multimodality therapy.

Skin Toxicity Profile of Photon Radiotherapy versus Proton Beam Therapy in Paediatric and Young Adult Patients with Sarcomas

AIMS

Radiotherapy is key in the management of patients with both Ewing sarcoma and rhabdomyosarcoma. However, there is little evidence in the literature with regards to radiation-induced skin toxicities (RISTs) for patients treated with conventional radiotherapy with X-rays (XRT) or proton beam therapy (PBT) for these two conditions. In the present study we evaluated acute and late RIST in patients treated within European protocols with either PBT or XRT, taking both clinical and dosimetric variables into consideration.

MATERIALS AND METHODS

This was a retrospective analysis of 79 paediatric/young adult patients treated with radical radiotherapy (with XRT or PBT) and concurrent chemotherapy. In all cases, radiotherapy was given in conventional fractionation (1.8 Gy/fraction). Acute and late RISTs were registered according to the Radiation Therapy Oncology Group (RTOG) scoring system.

RESULTS

With regards to acute RIST, 47.9% (23/48) of XRT patients and 48.4% (15/31) of PBT patients had acute grade 2/3 toxicity. When it comes to late RIST, 17.5% (7/40 with known toxicity profile) of XRT patients and 29.0% (9/31) of PBT patients had grade 1/2 toxicity. This difference of -11.5% (95% confidence interval -31.2 to 7.9%) in grade 1/2 toxicity between XRT and PBT was not statistically significant (P = 0.25). Regardless of the radiotherapy technique, V30Gy seems a good predictor of acute RIST. Moreover, for the same value of V30Gy, patients who receive PBT may have a higher risk of moderate-severe acute RIST. Perhaps due to the small sample, definitive conclusions on the predictive factors of late RIST could not be drawn.

CONCLUSIONS

No clinically meaningful differences in acute and late RIST were observed between PBT and XRT subgroups. Systematic differences in the modelling of the build-up region may exist between XRT and PBT algorithms, which could make the comparison of dose metrics between techniques potentially biased. A more comprehensive analysis of dosimetric data on larger patient cohorts is needed to elucidate the most relevant skin dose metrics. Dose-effect models of RIST for this unique patient population would be an invaluable tool in radiotherapy plan optimisation.

Late toxicity and outcomes following radiation therapy for chest wall sarcomas in pediatric patients

PURPOSE

To investigate the contribution of radiation therapy to acute and late toxicity in pediatric chest wall sarcoma patients and evaluate dosimetric correlates of higher incidence toxicities such as scoliosis and pneumonitis.

METHODS AND MATERIALS

The data from 23 consecutively treated pediatric patients with chest wall sarcomas of various histologies (desmoid, Ewing, rhabdomyosarcoma, nonrhabdomyosarcoma-soft tissue sarcomas) were reviewed to evaluate the relationship between end-organ radiation dose, clinical factors, and the risk of subsequent late effects (scoliosis, pneumonitis). Cobb angles were used to quantify the extent of scoliosis. Doses to the spine and lung were calculated from the radiation treatment plan.

RESULTS

The range of scoliosis identified on follow-up imaging ranged from -47.6 to 64° (median, 2.95°). No relationship was identified between either radiation dose to the ipsilateral or contralateral vertebral body or tumor size and the degree or direction of scoliosis. The extent of surgical resection and number and location of resected ribs affected the extent of scoliosis. The dominant predictor of extent of scoliosis at long-term follow-up was the extent of scoliosis following surgical resection. Radiation pneumonitis was uncommon and was not correlated with mean dose or volume of lung receiving 24 Gy; however, 1 of 3 surviving patients who received whole pleural surface radiation therapy developed significant restrictive lung disease.

CONCLUSIONS

Acute and late radiation therapy-associated toxicities in pediatric chest wall sarcoma patients are modest. The degree of scoliosis following resection is a function of the extent of resection and of the number and location of ribs resected, and the degree of scoliosis at the last follow-up visit is a function of the extent of scoliosis following surgery. Differential radiation therapy dose across the vertebral body does not increase the degree of scoliosis. Severe restrictive pulmonary disease is a late complication of survivors after whole pleural surface radiation therapy.

Quantification of patient-reported outcome measures of radiation-induced skin reactions for use in clinical trial design

PURPOSE

Skin toxicity is a common effect from radiotherapy, although difficult to predict on an individual basis, and there is little evidence-based management. This study aimed to quantify inter-patient variation in patient-reported outcome measures for radiation-induced skin reactions (RISR) to enable the determination of the number of patients required for adequate power in a comparative trial of RISR management strategies.

METHODS

The study included 154 patients scheduled to receive breast cancer radiotherapy. Patients filled in a weekly questionnaire during and up to 4 weeks following the end of radiotherapy scoring five aspects of their experience of RISR: skin redness, and bother from redness like itching, burning sensation and tenderness/pain.

RESULTS

Assessment of patients' reported experience of their RISR was shown to be feasible, with 91 % of patients returning at least two questionnaires. The mean score increase between weeks 1 and 4 was 25 points (p value <0.0001, 95 % CI 21-29), and the estimated standard deviation at 4 weeks was 18 (95 % CI 16-21).

CONCLUSIONS

Patients' assessment of their reaction was not predicted on the basis of treatment and patient-related characteristics. Based on the observed variance in scores at 4 weeks, we could calculate the sample size required for a comparative study of two RISR management policies would be 200 patients to have statistical power to detect a clinically significant difference in patient-rated scores of their skin reactions. A trial employing this tool would help provide an evidence base to guide policy in advising patients how to manage their RISR.

Acute Toxicity Grade 3 and 4 After Irradiation in Children and Adolescents: Results From the IPPARCA Collaboration

PURPOSE

In the context of oncologic therapy for children, radiation therapy is frequently indicated. This study identified the frequency of and reasons for the development of high-grade acute toxicity and possible sequelae.

MATERIALS AND METHODS

Irradiated children have been prospectively documented since 2001 in the Registry for the Evaluation of Side Effects After Radiation in Childhood and Adolescence (RiSK) database in Germany and since 2008 in the registry for radiation therapy toxicity (RADTOX) in Sweden. Data were collected using standardized, published forms. Toxicity classification was based on Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria.

RESULTS

As of June 2013, 1500 children have been recruited into the RiSK database and 485 into the RADTOX registry leading to an analysis population of 1359 patients (age range 0-18). A total of 18.9% (n=257) of all investigated patients developed high-grade acute toxicity (grades 3/4). High-grade toxicity of the bone marrow was documented for 63.8% (n=201) of those patients, oral mucositis for 7.6% (n=24), and dermatitis for 7.6% (n=24). Patients with high-grade acute toxicity received concomitant chemotherapy more frequently (56%) than patients with no or lower acute toxicity (31.5%). In multivariate analyses, concomitant chemotherapy, diagnosis of Ewing sarcoma, and total radiation dose showed a statistically noticeable effect (P≤.05) on acute toxicity, whereas age, concomitant chemotherapy, Hodgkin lymphoma, Ewing sarcoma, total radiation dose, and acute toxicity influenced the time until maximal late toxicity.

CONCLUSIONS

Generally, high-grade acute toxicity after irradiation in children and adolescence occurs in a moderate proportion of patients (18.9%). As anticipated, the probability of acute toxicity appeared to depend on the prescribed dose as well as concomitant chemotherapy. The occurrence of chronic toxicity correlates with the prior acute toxicity grade. Age seems to influence the time until maximal late toxicity but not the development of acute toxicity.

ROS-scavenger and radioprotective efficacy of the new PrC-210 aminothiol

To identify new aminothiol radioprotectors that are active when applied topically and have fewer side effects when administered systemically, a new family of aminothiol radioprotectors was designed and synthesized. Three key elements in the aminothiol design were, (1) small size for efficient transmembrane diffusion, (2) positive charged amines in alkyl backbone for strong ionic interaction with DNA backbone, and (3) a perpendicular, alkyl side-chain with a terminal thiol that is projected away from the DNA backbone to enable reactive oxygen species scavenging around DNA. Several in vitro assays were used to characterize the prototype aminothiol, PrC-210, for efficacy: protection against reactive oxygen species-induced plasmid DNA nicking, mass spectrometry to detect aminothiol-reactive oxygen species by-products, S. typhimurium mutagenesis, human cell growth inhibition, Western blot for p21 expression, and FACS analysis. Additionally, two in vivo assays were used to assess radioprotective efficacy; a Sprague-Dawley rat dorsal skin radiodermatitis assay was developed to screen for aminothiol efficacy when topically applied, and ICR mouse survival was scored after systemic PrC-210 administration and whole-body radiation. PrC-210 efficiently scavenged reactive oxygen species and completely protected supercoiled plasmid DNA against reactive oxygen species-induced damage. Neither PrC-210 nor its analog PrC-211 were bacterial mutagens. In cell culture, PrC-210 application to diploid human fibroblasts showed: (1) inhibition of cell growth with an IC(70) of 4.1 mM, (2) induced levels of p21 expression, and (3) a G(1)/S-cell cycle block that was reversed after washout of PrC-210-containing medium. In rodents, PrC-210 was an effective radioprotector showing: (1) complete prevention of Grade 2-3 radiodermatitis when applied topically (370 mM in ethanol:propylene glycol:water solution) prior to skin irradiation, (2) complete prevention of Grade 2-3 radiodermatitis when administered by i.p. injection (200 μg/g of body weight) before skin irradiation, (3) 100% survival of mice from an otherwise 100% lethal dose of whole-body radiation (8.75 Gy) when administered by i.p. injection (252 μg/g of body weight = 0.5 × maximum tolerated dose) before irradiation, and (4) a dose reduction factor of 1.6, the same as amifostine. These data suggest that the PrC-210 aminothiol is a plausible candidate for drug development as a human pre-exposure radioprotector.

Jaw dysfunction related to pterygoid and masseter muscle dosimetry after radiation therapy in children and young adults with head-and-neck sarcomas

PURPOSE

To investigate the relationship between jaw function, patient and treatment variables, and radiation dosimetry of the mandibular muscles and joints in children and young adults receiving radiation for soft-tissue and bone sarcomas.

METHODS AND MATERIALS

Twenty-four pediatric and young adult patients with head-and-neck sarcomas were treated on an institutional review board-approved prospective study of focal radiation therapy for local tumor control. Serial jaw depression measurements were related to radiation dosimetry delivered to the medial and lateral pterygoid muscles, masseter muscles, and temporomandibular joints to generate mathematical models of jaw function.

RESULTS

Baseline jaw depression was only influenced by the degree of surgical resection. In the first 12 weeks from initiation of radiation, surgical procedures greater than a biopsy, administration of cyclophosphamide containing chemotherapy regimes, and large gross tumor volumes adversely affected jaw depression. Increasing dose to the pterygoid and masseter muscles above 40 Gy predicted loss of jaw function over the full course of follow-up.

CONCLUSIONS

Clinical and treatment factors are related to initial and subsequent jaw dysfunction. Understanding these complex interactions and the affect of specific radiation doses may help reduce the risk for jaw dysfunction in future children and young adults undergoing radiation therapy for the management of soft-tissue and bone sarcomas.