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1.
Radiat Oncol ; 17(1): 10, 2022 Jan 20.
Article in English | MEDLINE | ID: covidwho-1643167

ABSTRACT

BACKGROUND: Low dose radiotherapy (LDRT) of whole lungs with photon beams is a novel method for treating COVID-19 pneumonia. This study aimed to estimate cancer risks induced by lung LDRT for different radiotherapy delivery techniques. METHOD: Four different radiotherapy techniques, including 3D-conformal with anterior and posterior fields (3D-CRT AP-PA), 3D-conformal with 8 coplanar fields (3D-CRT 8 fields), eight fields intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy using 2 full arcs (VMAT) were planned on the CT images of 32 COVID-19 patients with the prescribed dose of 1 Gy to the lungs. Organ average and maximum doses, and PTV dose distribution indexes were compared between different techniques. The radiation-induced cancer incidence and cancer-specific mortality, and cardiac heart disease risks were estimated for the assessed techniques. RESULTS: In IMRT and VMAT techniques, heart (mean and max), breast (mean, and max), and stomach (mean) doses and also maximum dose in the body were significantly lower than the 3D-CRT techniques. The calculated conformity indexes were similar in all the techniques. However, the homogeneity indexes were lower (i.e., better) in intensity-modulated techniques (P < 0.03) with no significant differences between IMRT and VMAT plans. Lung cancer incident risks for all the delivery techniques were similar (P > 0.4). Cancer incidence and mortality risks for organs located closer to lungs like breast and stomach were higher in 3D-CRT techniques than IMRT or VMAT techniques (excess solid tumor cancer incidence risks for a 30 years man: 1.94 ± 0.22% Vs. 1.68 ± 0.17%; and women: 6.66 ± 0.81% Vs. 4.60 ± 0.43%: cancer mortality risks for 30 years men: 1.63 ± 0.19% Vs. 1.45 ± 0.15%; and women: 3.63 ± 0.44% Vs. 2.94 ± 0.23%). CONCLUSION: All the radiotherapy techniques had low cancer risks. However, the overall estimated risks induced by IMRT and VMAT radiotherapy techniques were lower than the 3D-CRT techniques and can be used clinically in younger patients or patients having greater concerns about radiation induced cancers.


Subject(s)
COVID-19/radiotherapy , Neoplasms, Radiation-Induced/prevention & control , Radiotherapy Planning, Computer-Assisted , Adult , Aged , Breast/radiation effects , COVID-19/pathology , Female , Heart/radiation effects , Heart Disease Risk Factors , Humans , Iran , Lung/pathology , Lung/radiation effects , Male , Middle Aged , Neoplasms, Radiation-Induced/diagnosis , Neoplasms, Radiation-Induced/etiology , Organs at Risk/radiation effects , Pneumonia, Viral/radiotherapy , Prognosis , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Conformal/methods , Radiotherapy, Intensity-Modulated/methods , Retrospective Studies , Risk Assessment , SARS-CoV-2
3.
Int J Radiat Oncol Biol Phys ; 111(1): 233-239, 2021 09 01.
Article in English | MEDLINE | ID: covidwho-1209500

ABSTRACT

PURPOSE: The respiratory disease COVID-19 reached global pandemic status in 2020. Excessive inflammation is believed to result in the most severe symptoms and death from this disease. Because treatment options for patients with severe COVID-19 related pulmonary symptoms remain limited, whole-lung low-dose radiation therapy is being evaluated as an anti-inflammatory modality. However, there is concern about the long-term risks associated with low-dose pulmonary irradiation. To help quantify the benefit-risk balance of low-dose radiation therapy for COVID-19, we estimated radiation-induced lifetime risks of both lung cancer and heart disease (major coronary events) for patients of different sexes, treated at ages 50 to 85, with and without other relevant risk factors (cigarette smoking and baseline heart disease risk). METHODS AND MATERIALS: These estimates were generated by combining state-of-the-art radiation risk models for lung cancer and for heart disease together with background lung cancer and heart disease risks and age/sex-dependent survival probabilities for the U.S. RESULTS: Estimated absolute radiation-induced risks were generally higher for lung cancer compared with major coronary events. The highest estimated lifetime radiation-induced lung cancer risks were approximately 6% for female smokers treated between ages 50 and 60. The highest estimated radiation-induced heart disease risks were approximately 3% for males or females with high heart disease risk factors and treated between ages 50 and 60. CONCLUSIONS: The estimated summed lifetime risk of lung cancer and major coronary events reached up to 9% in patients with high baseline risk factors. Predicted lung cancer and heart disease risks were lowest in older nonsmoking patients and patients with few cardiac risk factors. These long-term risk estimates, along with consideration of possible acute reactions, should be useful in assessing the benefit-risk balance for low-dose radiation therapy to treat severe COVID-19 pulmonary symptoms, and suggest that background risk factors, particularly smoking, should be taken into account in such assessments.


Subject(s)
COVID-19/radiotherapy , Heart Diseases/etiology , Lung Neoplasms/etiology , Lung/radiation effects , Neoplasms, Radiation-Induced/etiology , Radiation Dosage , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Radiotherapy Dosage , Risk Factors
4.
BMJ Case Rep ; 13(12)2020 Dec 17.
Article in English | MEDLINE | ID: covidwho-1177537

ABSTRACT

Radiation-induced spinal glioblastoma is an extremely rare disease with only four previously published reports in the literature. We report the fifth case, a 69-year-old woman who previously underwent treatment with brachytherapy for cervical cancer, and thereafter presented with neurologic deficits from a conus medullaris tumour. Biopsy and histopathology confirm glioblastoma, not otherwise specified. Treatment of spinal glioblastoma consists of surgery, either biopsy or excision and chemoradiation. However, results are still unsatisfactory and prognosis remains poor.


Subject(s)
Brachytherapy/adverse effects , Glioblastoma/diagnosis , Neoplasms, Radiation-Induced/diagnosis , Spinal Cord Neoplasms/diagnosis , Uterine Cervical Neoplasms/radiotherapy , Aged , Biopsy , Cytoreduction Surgical Procedures , Female , Glioblastoma/etiology , Glioblastoma/pathology , Glioblastoma/surgery , Humans , Laminectomy , Magnetic Resonance Imaging , Neoplasms, Radiation-Induced/etiology , Neoplasms, Radiation-Induced/pathology , Neoplasms, Radiation-Induced/surgery , Spinal Cord/diagnostic imaging , Spinal Cord/pathology , Spinal Cord/radiation effects , Spinal Cord/surgery , Spinal Cord Neoplasms/etiology , Spinal Cord Neoplasms/pathology , Spinal Cord Neoplasms/surgery
5.
Int J Radiat Biol ; 97(2): 120-125, 2021.
Article in English | MEDLINE | ID: covidwho-915824

ABSTRACT

BACKGROUND: Recently, low dose radiotherapy delivered to the whole lung has been proposed as treatment for the pneumonia due to COVID-19. Although there is biological plausibility for its use, the evidence supporting its effectiveness is scarce, and the risks associated with it may be significant. Thus, based on a virtual case simulation, we estimated the risks of radiation-induced cancer (RIC) and cardiac disease. METHODS: Lifetime attributable risks (LAR) of RIC were calculated for the lung, liver, esophagus, and breast of female patients. The cardiovascular risk of exposure-induced death (REID) due to ischemic heart disease was also calculated. The doses received by the organs involved in the treatment were obtained from a simulation of conformal radiotherapy (RT) treatment, delivering a dose of 0.5 Gy-1.5 Gy to the lungs. We considered a LAR and REID <1% as acceptable, 1-2% cautionary, and >2% unacceptable. RESULTS: The lung was at the highest risk for RIC (absolute LAR below 5200 cases/100,000 and 2250 cases/100,000 for women and men, respectively). For women, the breast had the second-highest LAR, especially for young women. The liver and esophagus had LARs below 700/100,000 for both sexes, with a higher incidence of esophageal cancer in women and liver cancer in men. Regarding the LAR cutoff, we observed an unacceptable or cautionary LAR for lung cancer in all women and men <60 years with an RT dose >1 Gy. LAR for lung cancer with an RT dose of 1 Gy was cautionary for women >60 years of age and men <40 years of age. No LAR estimation was unacceptable for the RT dose ≤0.7 Gy in all groups irrespective of sex or age at exposure. Only 0.5 Gy had an acceptable REID. CONCLUSIONS: A RT dose ≤0.5 Gy provides an acceptable LAR estimate (≤1%) for RIC and REID, irrespective of sex and age. The current ongoing trials should initially use doses ≤0.5 Gy to maintain the risks at an acceptable level and include only patients who fail or do not have any other treatment option.


Subject(s)
COVID-19/radiotherapy , Lung/radiation effects , Myocardial Ischemia/etiology , Neoplasms, Radiation-Induced/etiology , Radiation Dosage , Female , Humans , Organs at Risk/radiation effects , Radiotherapy Dosage , Radiotherapy, Conformal/adverse effects , Risk Assessment , User-Computer Interface
6.
Phys Med ; 80: 119-124, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-893744

ABSTRACT

PURPOSE: The aim of this work was to evaluate the dosimetric impact of high-resolution thorax CT during COVID-19 outbreak in the University Hospital of Parma. In two months we have performed a huge number of thorax CT scans collecting effective and equivalent organ doses and evaluating also the lifetime attributable risk (LAR) of lung and other major cancers. MATERIALS AND METHOD: From February 24th to April 28th, 3224 high-resolution thorax CT were acquired. For all patients we have examined the volumetric computed tomography dose index (CTDIvol), the dose length product (DLP), the size-specific dose estimate (SSDE) and effective dose (E103) using a dose tracking software (Radimetrics Bayer HealthCare). From the equivalent dose to organs for each patient, LAR for lung and major cancers were estimated following the method proposed in BEIR VII which considers age and sex differences. RESULTS: Study population included 3224 patients, 1843 male and 1381 female, with an average age of 67 years. The average CTDIvol, SSDE and DLP, and E103 were 6.8 mGy, 8.7 mGy, 239 mGy·cm and 4.4 mSv respectively. The average LAR of all solid cancers was 2.1 cases per 10,000 patients, while the average LAR of leukemia was 0.2 cases per 10,000 patients. For both male and female the organ with a major cancer risk was lung. CONCLUSIONS: Despite the impressive increment in thoracic CT examinations due to COVID-19 outbreak, the high resolution low dose protocol used in our hospital guaranteed low doses and very low risk estimation in terms of LAR.


Subject(s)
COVID-19/epidemiology , Neoplasms, Radiation-Induced/etiology , Radiometry/methods , Thorax/diagnostic imaging , Tomography, X-Ray Computed/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Disease Outbreaks , Female , Humans , Lung/radiation effects , Male , Middle Aged , Models, Statistical , Radiation Dosage , Risk Assessment , Sex Factors , Software
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