Radiation-induced Malignancies Research Articles

Multiple squamous cell carcinomas of temporal bone years after radiotherapy for malignancy glottis-report of a rare case with review of literature

Larynx is unique in its anatomy. It is critical to map the lesions accurately so that the patient may benefit from the strategy most likely to preserve a functional larynx with the lowest likelihood of recurrence and the least morbidity. We describe a case of 60-year-old male with malignancy glottis diagnosed at the age of 43, treated with external beam radiotherapy, presented 15 years after with swelling in the right upper part of the face, lateral to the eye. Radiological investigations suggested neoplasm in the skin over the right zygomatic part of the temporal bone. Biopsy confirmed malignancy, basal cell carcinoma type. Wide local excision of the lesion with split skin grafting was done. After 2 years, he presented with right ear pain, discharge, and hard of hearing. Examination and radiological investigations confirmed a mass in the external auditory canal, infiltrating through the temporal bone. Biopsy revealed an acantholytic variant of squamous cell carcinoma (SCC). The patient was advised about treatment options and radiotherapy was chosen. Further, a literature search was conducted to detect similar cases. We describe the incidence and prevalence of radiation-induced temporal bone malignancy, an exceedingly rare and late complication of head and neck irradiation. Radiation induced SCCs are highly malignant secondary neoplasms in the head and neck region. It constitutes a therapeutic challenge because of its anatomy and the known side effects of radiation. Timely intervention with a multidisciplinary approach is necessary.

Abstract 1124: Prevention of radiation-induced malignancies in Li-Fraumeni syndrome

Abstract PURPOSE: Li-Fraumeni Syndrome (LFS) is a genetic disorder associated with a significant risk of early-onset cancer. This condition is driven by germline mutations in the TP53 gene which plays a primary role in the regulation of the radiation response. Aberrant TP53 function contributes to radiation vulnerability and a greater risk of secondary, radiation-induced malignancies (RIMs). As a result, therapeutic options for LFS patients are often limited to exclude radiotherapy (RT), which may otherwise be beneficial for the treatment of certain primary tumors. Data from our lab demonstrate an aberrant transcriptomic response to irradiation (IR) in mutant p53 patient skin fibroblasts compared to wildtype; however, it is unknown whether reprogramming this radiation response can decrease the risk of RIM in LFS. Metformin, a commonly prescribed anti-diabetic drug, is associated with lower cancer incidence and may decrease cancer-related mortality in murine LFS models. In addition to its potential anti-tumorigenicity, studies have shed light on the ability of metformin to prevent IR-induced damage in normal tissue; hence, we hypothesize that metformin can reprogram the radiation response to protect against radiation injury and delay the onset of RIM in LFS. METHODS: To establish a murine model of RIM in LFS, and to investigate whether metformin can delay tumor onset in this model, whole-body or localized IR were administered to mice harboring a hotspot Trp53R172H/+ mutation in the presence and absence of metformin. Serial MRI was conducted to monitor for tumor development. To understand the effect of metformin on the mutant p53 radiation response in vivo, a similar murine workflow was established and irradiated skin was collected longitudinally from untreated and metformin-treated cohorts for whole transcriptome sequencing. Sequencing data were functionally validated in a separate cohort of mice using flow cytometry. In parallel, we performed RNA sequencing on LFS patient fibroblasts to characterize the effect of metformin on the human radiation response. RESULTS: We demonstrate that IR decreases tumor latency in TP53R172H/+ mice, and that metformin significantly delays tumor onset within the radiation field. Moreover, transcriptomic data revealed that metformin upregulates apoptosis following IR in TP53R172H/+ mice. Flow cytometry analysis of the radiation response validated these findings, demonstrating that metformin promotes the apoptosis-driven clearance of damaged, potentially tumorigenic cells following IR. Transcriptomic data from patient cell lines will be presented. CONCLUSIONS: Overall, we show that metformin may delay RIM in LFS mice, and have begun to characterize the biology underpinning this reprogrammed response to IR. This study is the first to highlight metformin as a radioprotective agent in the context of germline mutant p53, with the potential to broaden RT treatment options for LFS patients. Citation Format: Pamela Psarianos, Nicholas Fischer, David Malkin. Prevention of radiation-induced malignancies in Li-Fraumeni syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1124.

Imaging of the Posttreatment Head and Neck: Expected Findings and Potential Complications.

Interpretation of posttreatment imaging findings in patients with head and neck cancer can pose a substantial challenge. Malignancies in this region are often managed through surgery, radiation therapy, chemotherapy, and newer approaches like immunotherapy. After treatment, patients may experience various expected changes, including mucositis, soft-tissue inflammation, laryngeal edema, and salivary gland inflammation. Imaging techniques such as CT, MRI, and PET scans help differentiate these changes from tumor recurrence. Complications such as osteoradionecrosis, chondroradionecrosis, and radiation-induced vasculopathy can arise because of radiation effects. Radiation-induced malignancies may occur in the delayed setting. This review article emphasizes the importance of posttreatment surveillance imaging to ensure proper care of patients with head and neck cancer and highlights the complexities in distinguishing between expected treatment effects and potential complications. Keywords: CT, MR Imaging, Radiation Therapy, Ear/Nose/Throat, Head/Neck, Nervous-Peripheral, Bone Marrow, Calvarium, Carotid Arteries, Jaw, Face, Larynx © RSNA, 2024.

Involvement of Cannabinoid Receptors and Adenosine A2B Receptor in Enhanced Migration of Lung Cancer A549 Cells Induced by γ-Ray Irradiation.

Residual cancer cells after radiation therapy may acquire malignant phenotypes such as enhanced motility and migration ability, and therefore it is important to identify targets for preventing radiation-induced malignancy in order to increase the effectiveness of radiotherapy. G-Protein-coupled receptors (GPCRs) such as adenosine A2B receptor and cannabinoid receptors (CB1, CB2, and GPR55) may be involved, as they are known to have roles in proliferation, invasion, migration and tumor growth. In this study, we investigated the involvement of A2B and cannabinoid receptors in γ-radiation-induced enhancement of cell migration and actin remodeling, as well as the involvement of cannabinoid receptors in cell migration enhancement via activation of A2B receptor in human lung cancer A549 cells. Antagonists or knockdown of A2B, CB1, CB2, or GPR55 receptor suppressed γ-radiation-induced cell migration and actin remodeling. Furthermore, BAY60-6583 (an A2B receptor-specific agonist) enhanced cell migration and actin remodeling in A549 cells, and this enhancement was suppressed by antagonists or knockdown of CB2 or GPR55, though not CB1 receptor. Our results indicate that A2B receptors and cannabinoid CB1, CB2, and GPR55 receptors all contribute to γ-radiation-induced acquisition of malignant phenotypes, and in particular that interactions of A2B receptor and cannabinoid CB2 and GPR55 receptors play a role in promoting cell migration and actin remodeling. A2B receptor-cannabinoid receptor pathways may be promising targets for blocking the appearance of malignant phenotypes during radiotherapy of lung cancer.

Second Malignancy Probabilities in Patients With Breast Cancer Treated With Conventional Versus Hypofractionated External Beam Radiation Therapy in the Adjuvant Setting

AimsFor women with breast cancer, seminal studies have shown that adjuvant hypofractionated external beam radiation therapy (hEBRT) maintains similar outcomes and may reduce overall costs compared with conventionally fractionated external beam radiation therapy (cEBRT). However, it is unclear whether hEBRT may be associated with differential risk of development of radiation-induced second malignancies compared with cEBRT. Because the occurrence of second malignancies is small, large databases may improve our understanding of the relative risk of second malignancies between hEBRT and cEBRT. Materials and methodsUsing the National Cancer Database, we carried out a retrospective cohort analysis of women diagnosed with non-metastatic, stage 0–III breast cancer from 2004 to 2017. All patients had a lumpectomy or mastectomy and a follow-up time of at least 60 months after diagnosis. The probability of second malignancies in women receiving adjuvant cEBRT or hEBRT was compared using multivariable logistic regression adjusting for sociodemographic, geographical, clinical and treatment factors, allowing for relative (but not absolute) comparison of second malignancy risk. Temporal sensitivity analyses stratified by year of diagnosis and length of follow-up time were also conducted. ResultsOf the 125 228 women in our study, 115 576 (92.3%) received cEBRT and 9652 (7.71%) received hEBRT. The median age of the cohort was 60 (interquartile range 51–68) years at diagnosis and the median follow-up time was 99.61 (interquartile range 77.5–128.49) months. Upon adjusting for sociodemographic and clinical factors, patients who received hEBRT had no difference in relative risk than patients who received cEBRT (odds ratio 0.937, 95% confidence interval 0.869–1.010, P = 0.091). In analyses stratified by year of diagnosis, and stratified by length of follow-up, there was no difference in second malignancy probability between patients who completed hEBRT and patients who completed cEBRT. ConclusionsIn this analysis of over 120 000 women with non-metastatic breast cancer, hEBRT was not associated with different odds of developing second malignancies compared with cEBRT. Our findings may inform patient counselling in the choice of radiation regimens for breast cancer and further support the safety of hypofractionated regimens for breast cancer.

Proton Therapy for Advanced Juvenile Nasopharyngeal Angiofibroma.

To provide the first report on proton radiotherapy (PRT) in the management of advanced nasopharyngeal angiofibroma (JNA) and evaluate potential benefits compared to conformal photon therapy (XRT). We retrospectively reviewed 10 consecutive patients undergoing PRT for advanced JNA in a definitive or postoperative setting with a relative biological effectiveness weighted dose of 45 Gy in 25 fractions between 2012 and 2022 at the Heidelberg Ion Beam Therapy Center. Furthermore, dosimetric comparisons and risk estimations for short- and long-term radiation-induced complications between PRT plans and helical XRT plans were conducted. PRT was well tolerated, with only low-grade acute toxicities (CTCAE I-II) being reported. The local control rate was 100% after a median follow-up of 27.0 (interquartile range 13.3-58.0) months. PRT resulted in considerable tumor shrinkage, leading to complete remission in five patients and bearing the potential to provide partial or complete symptom relief. Favorable dosimetric outcomes in critical brain substructures by the use of PRT translated into reduced estimated risks for neurocognitive impairment and radiation-induced CNS malignancies compared to XRT. PRT is an effective treatment option for advanced JNA with minimal acute morbidity and the potential for reduced radiation-induced long-term complications.

Very low-dose radiotherapy for extranodal marginal zone lymphoma of bronchus-associated lymphoid tissue

Extranodal marginal zone lymphoma of bronchus-associated lymphoid tissue (BALT) is a rare cancer for which optimal treatment strategies are undefined. Retrospective analyses suggest excellent outcomes with surgical resection for localized BALT lymphoma; however, the role of radiotherapy remains underexplored. We report the largest-to-date single-center analysis of 13 primary BALT lymphoma patients treated with radiotherapy. Of 15 treated lesions, we report a 100% response rate with complete response (CR) achieved in 67% of lesions. Among 10 lesions treated with very low-dose radiotherapy (VLDRT; 4 Gray [Gy]), 6 (60%) achieved a CR; among 5 lesions treated with full-dose radiotherapy (24–36 Gy), 4 (80%) achieved a CR. There were no local recurrences. Only one patient, treated with 30 Gy, developed an acute grade 3/4 toxic effect. There were no events of radiation-induced secondary malignancies. Our institutional experience indicates that radiotherapy, including VLDRT, is a safe and effective treatment for primary BALT lymphoma.

99 Characterization of the Radiation Response and Prevention of Radiation-Induced Malignancies in Li-Fraumeni Syndrome

99 Characterization of the Radiation Response and Prevention of Radiation-Induced Malignancies in Li-Fraumeni Syndrome

Hybrid planning techniques for early-stage left-sided breast cancer: dose distribution analysis and estimation of projected secondary cancer-relative risk

Purpose The purpose of this study was to evaluate three techniques of irradiation of left-sided breast cancer patients, three-dimensional conformal radiotherapy (3D-CRT), hybrid Intensity-Modulated Radiotherapy (h-IMRT), and hybrid Volumetric-Modulated Arc Therapy (h-VMAT, h-ARC), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim was to estimate the projected relative risk of radiation-induced secondary cancers for hybrid techniques. Materials and methods Three treatment plans were prepared in 3D-CRT, h-IMRT, and h-VMAT techniques for each of the 40 patients, who underwent CT simulation in deep inspiration breath-hold (DIBH). For hybrid techniques, plans were created by combining 3D-CRT and dynamic fields with an 80%/20% dose ratio for 3D-CRT and IMRT or VMAT. Cumulative dose–volume histograms were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], left and right lung [LL, RL], right breast [RB]). Projected risk ratios for secondary cancers were estimated relative to 3D-CRT using the organ equivalent dose (OED) concept for the Schneider’s linear exponential, plateau, and full mechanistic dose–response model. Results All plans fulfilled the PTV criterium: V95%≥95%. Compared to 3D-CRT, both hybrid techniques showed significantly better target coverage (PTV: V95%>98%, p < 0.001), and the best conformality was achieved by h-ARC plans (CI: 1.18 ± 0.09, p < 0.001). Compared to 3D-CRT and h-ARC, h-IMRT increased the average sum of monitor units (MU) over 129.9% (p < 0.001). H-ARC increased the mean dose of contralateral organs and the LL V5Gy parameter (p < 0.001). Both hybrid techniques significantly reduced the D max of the heart by 5 Gy. Compared to h-IMRT, h-ARC increased secondary cancer projected relative risk ratios for LL, RL, and RB by 18, 152, and 81%, respectively. Conclusions The results confirmed that both hybrid techniques provide better target quality and OARs sparing than 3D-CRT. Hybrid VMAT delivers less MU compared to hybrid IMRT but may increase the risk of radiation-induced secondary malignancies.

Impact of GADD45A on Radiation Biodosimetry Using Mouse Peripheral Blood.

High-dose-radiation exposure in a short period of time leads to radiation syndromes characterized by severe acute and delayed organ-specific injury accompanied by elevated organismal morbidity and mortality. Radiation biodosimetry based on gene expression analysis of peripheral blood is a valuable tool to detect exposure to radiation after a radiological/nuclear incident and obtain useful biological information that could predict tissue and organismal injury. However, confounding factors, including chronic inflammation, can potentially obscure the predictive power of the method. GADD45A (Growth arrest and DNA damage-inducible gene a) plays important roles in cell growth control, differentiation, DNA repair, and apoptosis. GADD45A-deficient mice develop an autoimmune disease, similar to human systemic lupus erythematosus, characterized by severe hematological disorders, kidney disease, and premature death. The goal of this study was to elucidate how pre-existing inflammation in mice, induced by GADD45A ablation, can affect radiation biodosimetry. We exposed wild-type and GADD45A knockout male C57BL/6J mice to 7 Gy of X rays and 24 h later RNA was isolated from whole blood and subjected to whole genome microarray and gene ontology analyses. Dose reconstruction analysis using a gene signature trained on gene expression data from irradiated wild-type male mice showed accurate reconstruction of either a 0 Gy or 7 Gy dose with root mean square error of ± 1.05 Gy (R^2 = 1.00) in GADD45A knockout mice. Gene ontology analysis revealed that irradiation of both wild-type and GADD45A-null mice led to a significant overrepresentation of pathways associated with morbidity and mortality, as well as organismal cell death. However, based on their z-score, these pathways were predicted to be more significantly overrepresented in GADD45A-null mice, implying that GADD45A deletion may exacerbate the deleterious effects of radiation on blood cells. Numerous immune cell functions and quantities were predicted to be underrepresented in both genotypes; however, differentially expressed genes from irradiated GADD45A knockout mice predicted an increased deterioration in the numbers of T lymphocytes, as well as myeloid cells, compared with wild-type mice. Furthermore, an overrepresentation of genes associated with radiation-induced hematological malignancies was associated with GADD45A knockout mice, whereas hematopoietic and progenitor cell functions were predicted to be downregulated in irradiated GADD45A knockout mice. In conclusion, despite the significant differences in gene expression between wild-type and GADD45A knockout mice, it is still feasible to identify a panel of genes that could accurately distinguish between irradiated and control mice, irrespective of pre-existing inflammation status.

Esophageal Neuroendocrine Carcinoma Presenting After Definitive Chemoradiation of Squamous Cell Carcinoma in the Same Location

ABSTRACT Esophageal neuroendocrine carcinoma is very rare and highly aggressive. An 85-year-old man with a history of esophageal squamous cell carcinoma in remission presented 4 years after definitive chemoradiation with new-onset dysphagia. Endoscopy with biopsy revealed high-grade malignancy consistent with neuroendocrine carcinoma. Treatment options were limited to chemotherapy because of his metastatic disease, and he unfortunately died 14 months after diagnosis. The occurrence of esophageal neuroendocrine carcinoma in a site of prior squamous cell carcinoma is very uncommon, and this likely represents a case of radiation-induced malignancy. Therefore, when undergoing radiotherapy, patients and providers should discuss the possibility of this life-threatening complication.

Patient and Fetal Radiation-Induced Malignancy Risk From Imaging For Evaluation of Pulmonary Embolism in Pregnancy

BackgroundImaging for diagnosis of suspected pulmonary embolism in pregnancy presents radiation concerns for patient and fetus. ObjectivesEstimate the risks of radiation-induced breast cancer and childhood leukemia from common imaging techniques for the evaluation of suspected pulmonary embolism in pregnancy. MethodsBreast and uterine absorbed doses for various imaging techniques were input into the National Cancer Institute Radiation Risk Assessment Tool to calculate risk of breast cancer for the patient and childhood leukemia for the fetus. Absorbed doses were obtained by synthesizing data from a recent systematic review and the International Commission on Radiological Protection. Primary outcomes were the estimated excess incidences of breast cancer and childhood leukemia per 100,000 exposures. ResultsBaseline incidences of breast cancer for a 30-year-old woman and childhood leukemia for a male fetus were 13,341 and 939, respectively. Excess incidences of breast cancer were 0.003 and 0.275 for a single and two-view chest radiograph, respectively, 9.53 and 20.6 for low- and full-dose computed tomography pulmonary angiography (CTPA), respectively, 0.616 and 2.54 for low- and full-dose perfusion scan, respectively, and 0.732 and 2.66 for low- and full-dose ventilation perfusion scan, respectively. Excess incidences of childhood leukemia were 0.004 and 0.007 for a single and two-view chest radiograph, respectively, 0.069 and 0.490 for low- and full-dose CTPA, respectively, 0.359 and 1.47 for low- and full-dose perfusion scan, respectively, and 0.856 and 1.97 for low- and full-dose ventilation perfusion scan, respectively. ConclusionExcess cancer risks for all techniques were small relative to baseline cancer risks, with CTPA techniques carrying slightly higher risk of breast cancer for the patient and ventilation perfusion techniques a higher risk of childhood leukemia.

Multi-Phenotypic Breast Cancer Post-Radiotherapy for Hodgkin Lymphoma: A Case of Secondary Malignancy.

Morbidity and mortality associated with radiation-induced secondary malignancies (RISMs) have shifted treatment paradigms to minimize or eliminate radiation from treatment regimens. In this case, a 48-year-old woman was diagnosed with Hodgkin lymphoma (HL) and treated with radiotherapy in 2000. In 2018, she was diagnosed with ductal carcinoma in situ (DCIS) of the right breast and treated with a mastectomy. Soon after, she developed triple-negative invasive ductal carcinoma (IDC) in her reconstructed breast. The patient underwent a left lumpectomy, and pathology showed ER-/PR-/HER2+ IDC. This patient's multi-phenotypic DCIS and IDC presentation are suspected to be RISM due to her previous HL treatment regimen.

Overexpression of Both Human Sodium Iodide Symporter (NIS) and BRG1-Bromodomain Synergistically Enhances Radioiodine Sensitivity by Stabilizing p53 through NPM1 Expression.

Improved therapeutic strategies are required to minimize side effects associated with radioiodine gene therapy to avoid unnecessary damage to normal cells and radiation-induced secondary malignancies. We previously reported that codon-optimized sodium iodide symporter (oNIS) enhances absorption of I-131 and that the brahma-associated gene 1 bromodomain (BRG1-BRD) causes inefficient DNA damage repair after high-energy X-ray therapy. To increase the therapeutic effect without applying excessive radiation, we considered the combination of oNIS and BRG1-BRD as gene therapy for the most effective radioiodine treatment. The antitumor effect of I-131 with oNIS or oNIS+BRD expression was examined by tumor xenograft models along with functional assays at the cellular level. The synergistic effect of both BRG1-BRD and oNIS gene overexpression resulted in more DNA double-strand breaks and led to reduced cell proliferation/survival rates after I-131 treatment, which was mediated by the p53/p21 pathway. We found increased p53, p21, and nucleophosmin 1 (NPM1) in oNIS- and BRD-expressing cells following I-131 treatment, even though the remaining levels of citrulline and protein arginine deiminase 4 (PAD4) were unchanged at the protein level.

261 - Radiation-induced secondary malignancies: a case of multi-phenotypic breast cancer post-radiotherapy for Hodgkin lymphoma

261 - Radiation-induced secondary malignancies: a case of multi-phenotypic breast cancer post-radiotherapy for Hodgkin lymphoma

Hypo-fractionated Gamma Knife Radiosurgery for Intra-cranial Pathologies: A Single-Center Prospective Analysis of Feasibility, Safety, Efficacy, and Complication Profile.

Single-session stereotactic radiosurgery (SRS) is a proven and effective treatment modality for various benign, malignant, and functional intra-cranial pathologies. In certain situations, single-fraction SRS is limited because of lesion size and location. Hypo-fractionated gamma knife radiosurgery (hfGKRS) is an alternative approach for such unconventional indications. To evaluate the feasibility, efficacy, safety, and complication profile of hfGKRS with evaluation of different fractionation schemes and dosing patterns. The authors prospectively evaluated 202 patients treated with frame-based hfGKRS over a 9-year period. GKRS was administered fractionated because of either a large volume (>14 cc) or an inability to spare neighboring organs at risk from permissible radiation in single-session GKRS. The inter-fraction interval was kept at 24 hours, and the dose calculation was performed with linear quadratic equations. Patients with more than 3 years of clinical and radiological follow-up were included in prospective analysis. At pre-decided follow-up criteria, treatment effects and side effects were documented on objective scales. A total of 169/202 patients met inclusion criteria. 41% patients received treatment in three fractions, whereas 59% received two-fraction GKRS. Two patients of giant cavernous sinus hemangiomas were treated with 5 Gy in the five-fraction regimen. In patients with more than 3 years of follow-up, the obliteration rate was 88% for complex arteriovenous malformations (AVMs) treated with hfGKRS because of eloquent locations, whereas it was 62% for Spetzler-Martin grade 4-5 AVMs. For non-AVM pathologies (meningiomas, schwannomas, pituitary adenomas, paragangliomas, hypothalamic hamartomas, etc.), the 5-year progression free survival was 95%. Tumor failure was noted in 0.05% patient population. Radiation necrosis developed in 8.1% patients, and radiation-induced brain edema developed in 12% patients. It was resistant to treatment in 4% patients. No patient developed radiation-induced malignancy. Hypo-fractionation did not provide any hearing improvement in giant vestibular schwannomas. hfGKRS is a valuable standalone treatment option for candidates unsuitable for single-session GKRS. The dosing parameters need to be tailored as per the pathology and neighboring structures. It provides comparable results to single-session GKRS with an acceptable safety and complication profile.

Identification and characterization of patients being exposed to computed-tomography associated radiation-doses above 100 mSv in a real-life setting.

Rationale and objectivesPatients receiving high cumulative effective doses (CED) from recurrent computed tomography (CT) in a real-life setting are not well identified. Evaluation of causes and patient characteristics may help to define individuals potentially at risk of radiation-induced secondary malignancies. Materials and methodsPatients who received a CED > 100 mSv from CT scans during October 2012 and April 2020 at a tertiary university center were identified with the help of a radiological radiation dose monitoring system. The primary disease and referral diagnosis, number of CT exams, time period, age, BMI and gender distribution of the 1000 patients with the highest CED were analysed. Results3431 patients had a CED of more than 100 mSv, which corresponded to 2.75% of all patients who received a CT exam. From the 1000 patients with the highest CED, mean number of CT exams per patient was 14.6, mean CED was 257 mSv (SD 98, range 177–1339). Mean age of patients was 63.9 years (SD 10.6), male to female ratio 3:2, and mean BMI 28.7 kg/m2 (SD 5.5). 728 (72.9%) patients had cancer. The leading primary diagnosis was liver cirrhosis in 197 patients and 103 patients had a liver transplantation. In patients with liver cirrhosis, 750 exams were indicated for the follow-up of the disease, 662 for the clarification of an acute clinical condition, and 202 for CT-guided stereotactic radiofrequency ablation. ConclusionRecurrent CT scans of patients with cancer, liver cirrhosis and liver transplantation may lead to critically high CED.

Radiation exposure estimation in pediatric patients during computed tomography imaging procedures

Computed tomography (CT) procedures are the largest source of medical radiation exposure in children and adults. Numerous children undergo high-radiation-dose examinations due to the increasing utilization of CT in children and the wide range of radiation doses. It is therefore necessary to protect pediatric patients, because of their higher sensitivity to ionizing radiation. This study aimed to establish a multicenter cohort of pediatric patients who received CT scans and predict the radiation-related cancer risk. Ninety-five patients who underwent various CT scans [brain 64 (67.4%), chest 14 (14.7%), abdomen 17 (17.9%)] were referred to one of three hospitals. All patients were examined using one of three identical multi-detector CT machines (Toshiba Aquilion 64) according to standard departmental imaging protocols. The average effective doses per scan for brain, chest, and abdominal procedures were 49.7, 34, and 40 mSv, respectively. Dose-reduction measures might significantly decrease the number of radiation-induced malignancies in children.

Radiation-induced soft tissue sarcoma of the neck after radiation therapy for Hodgkin's lymphoma: a clinical case

Background. Radiation-induced malignancies are one of the long-term complications of radiation therapy, which is widely used to treat some tumors. The latency period before a second tumor develops varies from 3 to 60 years. Epithelial tumors and hemoblastoses occur after low-dose radiation therapy and sarcomas after high-dose radiation therapy.&#x0D; Aim. To present a case of radiation-induced soft tissue angiosarcoma of the neck after the cure of Hodgkin's disease.&#x0D; Materials and methods. A 41-year-old patient with Hodgkin's nodular lymphoma with the lymphoid predominance of stage IIIA with involvement of the right cervical and clavicular lymph nodes, mediastinum, and abdominal lymph nodes was followed-up. In 2004 the patient underwent four cycles of polychemotherapy per ABVD regimen followed by radiotherapy of the right cervical and clavicular lymph nodes and mediastinum, with a total focal dose of 40 Gy.&#x0D; Results. Seventeen years after the treatment for Hodgkin's disease, including radiation therapy, the patient presented with painful swelling of the neck soft tissues in the radiation area with the transition to the anterior thoracic wall and an enlarged cervical lymph node. A lymph node dissection was performed. According to the combined positron emission tomography and X-ray computed tomography (PET/CT), histological and immunohistochemical studies, epithelioid angiosarcoma of soft tissues of the neck and thoracic wall stage IV cT2N1M1G3 with metastases to the skeleton bones, neck lymph nodes, left adrenal gland was established. Surgical treatment was not performed due to advanced disease. The patient received six cycles of polychemotherapy with doxorubicin + ifosfamide. PET/CT confirmed partial tumor regression.&#x0D; Conclusion. Radiation-induced soft tissue sarcoma is a late iatrogenic complication of radiation therapy for Hodgkin's lymphoma. The tumor occurred in the radiation area. PET/CT is the method of choice in diagnosing and evaluating the extent of cancer and response to treatment. Chemotherapy, as an option for complex treatment, can achieve adequate disease control when surgery is not feasible.

Validation of Prediction Rules for Computed Tomography Use in Children With Blunt Abdominal or Blunt Head Trauma: Protocol for a Prospective Multicenter Observational Cohort Study.

Traumatic brain injuries (TBIs) and intra-abdominal injuries (IAIs) are 2 leading causes of traumatic death and disability in children. To avoid missed or delayed diagnoses leading to increased morbidity, computed tomography (CT) is used liberally. However, the overuse of CT leads to inefficient care and radiation-induced malignancies. Therefore, to maximize precision and minimize the overuse of CT, the Pediatric Emergency Care Applied Research Network (PECARN) previously derived clinical prediction rules for identifying children at high risk and very low risk for IAIs undergoing acute intervention and clinically important TBIs after blunt trauma in large cohorts of children who are injured. This study aimed to validate the IAI and age-based TBI clinical prediction rules for identifying children at high risk and very low risk for IAIs undergoing acute intervention and clinically important TBIs after blunt trauma. This was a prospective 6-center observational study of children aged <18 years with blunt torso or head trauma. Consistent with the original derivation studies, enrolled children underwent routine history and physical examinations, and the treating clinicians completed case report forms prior to knowledge of CT results (if performed). Medical records were reviewed to determine clinical courses and outcomes for all patients, and for those who were discharged from the emergency department, a follow-up survey via a telephone call or SMS text message was performed to identify any patients with missed IAIs or TBIs. The primary outcomes were IAI undergoing acute intervention (therapeutic laparotomy, angiographic embolization, blood transfusion, or intravenous fluid for ≥2 days for pancreatic or gastrointestinal injuries) and clinically important TBI (death from TBI, neurosurgical procedure, intubation for >24 hours for TBI, or hospital admission of ≥2 nights due to a TBI on CT). Prediction rule accuracy was assessed by measuring rule classification performance, using standard point and 95% CI estimates of the operational characteristics of each prediction rule (sensitivity, specificity, positive and negative predictive values, and diagnostic likelihood ratios). The project was funded in 2016, and enrollment was completed on September 1, 2021. Data analyses are expected to be completed by December 2022, and the primary study results are expected to be submitted for publication in 2023. This study will attempt to validate previously derived clinical prediction rules to accurately identify children at high and very low risk for clinically important IAIs and TBIs. Assuming successful validation, widespread implementation is then indicated, which will optimize the care of children who are injured by better aligning CT use with need. RR1-10.2196/43027.