Cancer risk after radiotherapy for benign diseases

Treatment of Darier Disease with Radiation Therapy: Case Report and Literature Review

Darier's disease (DD) is an autosomal dominant genodermatosis characterized by hyperkeratotic papules, often accompanied by scaling and crusting. Managing DD presents significant challenges due to the absence of an effective cure, with only symptom targeting treatments currently available. This study presents a case of refractory DD that showed poor response to established pharmacological treatments but demonstrated improvement with low-dose superficial X-ray radiotherapy (SRT). The radiation was delivered as a single 200 cGy treatment, which visibly improved the condition. Considering the different degrees of side effects, sequelae, and risk of developing radiation-induced cancer after exposure to moderate levels of radiation, it may be considered that we attempt to treat recalcitrant DD initially by applying a low dose of radiation in order to mitigate these undesired side effects. If larger doses or additional courses are necessary due to inadequate response, the risks and benefits must be carefully evaluated and discussed with patients.

Radiotherapy for aseptic granulomatous dermatitis: A case report

Granulomatous dermatitis is a common tissue reaction pattern seen in the skin or systematically in various presentations. Granulomatous dermatitis can be subclassified into infectious and non-infectious categories. This article focuses on a patient with non-infectious granulomatous dermatitis followed for many years. Past medical history included bilateral total shoulder arthroplasty complicated by prosthetic joint infections. In its early stages, the axillary rash was painful and had many fluid-filled blisters. Ultimately, the histology of the rash deemed the lesion non-infectious and mostly due to an inflammatory process. Specifically, ionizing radiation was used for this patient. The category of granulomatous processes is broad and there are many subtypes. Other treatment options for non-infectious granulomatous processes may include corticosteroids, phototherapy, and interferon-gamma injections. The differential for granulomatous processes is extensive and treatment should be decided on a case-by-case basis.

Low-dose radiation therapy for COVID-19 pneumonia: Comparison of dosimetry and life-time attributable risk of cancer with conventional AP-PA fields and bone marrow sparing VMAT

PURPOSE

Low-dose radiation therapy (LDRT) to lungs did show encouraging results in COVID-19 patients in some clinical trials. However, there has been some concern regarding the long-term risk of radiation-induced cancer (RIC). Compared to the conventional AP-PA field technique, volumetric modulated arc therapy (VMAT) can potentially reduce the dose to the marrow and other organs at risk (OARs) and thus minimize the risk of cancer. We designed a dosimetry study to study if VMAT can reduce the exposure to the marrow and other OAR doses and curtail the estimated life-time attributable risk (LAR) of cancer.

METHODS AND MATERIALS

We retrieved the computed tomography scan data of 10 patients (aged 40-60 years, median 48 years) who have been already treated for any malignancy in the region of the thorax. A dose of 1.0 Gy in single fraction was prescribed to both lungs. All the organs were delineated as per the established guidelines. The dosimetry achieved by the two plans was compared to find the difference. Mean OAR doses were used to estimate the LAR for both plans and compared.

RESULTS

Planning target volume coverage parameters like conformity index and homogeneity index were significantly better with VMAT (P value < 0.05 for all). The mean dose to most OARs was significantly lower with VMAT (P value < 0.05 for all). The mean dose to the marrow was significantly lower with VMAT (59.05 vs 81.9 cGy with P value < 0.05). The overall LAR was significantly lower with VMAT as compared to the conventional plan (0.357% vs 0.398%, P value < 0.05).

CONCLUSION

Compared to the conventional technique, VMAT provides better OAR dosimetry for lung irradiation (a prescription dose of 1.0 Gy or more) in COVID-19 pneumonia. VMAT significantly reduces the risk of RIC. We therefore suggest if lung LDRT is used for COVID-19 patients, VMAT is the preferred technique for a prescription dose of ≥1.0 Gy.

Role of external radiation in benign tumors: A clinical outcome and safety audit of 7 years from a tertiary care center in India

PURPOSE

Radiotherapy (RT) is a well-established modality for treating malignancies, but its role in treatment of benign lesions has not been well explored. Herein, we present a retrospective analysis of a 7-year data regarding the benefit and the safety profile of RT for treating benign tumors in our institute.

MATERIALS AND METHODS

Data of 23 patients who received RT for benign tumors from January 2015 to April 2022 were retrieved, and a retrospective analysis was conducted. All the pertinent demographic data, treatment and follow-up data were retrieved. The most common presentations were nasopharyngeal angiofibroma, vertebral hemangioma, paraganglioma, and others. The most common sites of occurrence were head and neck (43%) and paravertebral region (22%). Volumetric modulated arc therapy was the most commonly employed RT technique (39%), followed by three-dimensional conformal RT (34%) and two-dimensional conventional radiotherapy (26%). The median RT dose delivered was 36 Gy (range: 20-54 Gy).

RESULTS

The median follow-up duration was 53 months (range: 3-120 months). Nine (39%) patients had progressive disease with a median time to progression of 8 months (range: 1-30 months). The median disease-free survival (DFS) was 70 months, while the 1-, 3-, and 5-year DFS rates were 97%, 88%, and 62%, respectively. Four patients (17%) died, all due to disease progression. The 1-, 3-, and 5-year overall survival rates was 97%, 85%, and 50%, respectively. The rate of radiation-induced cancer (RIC) was 0% as none of the patients had developed RIC secondary to radiation.

CONCLUSION

RT is a safe and an effective option to manage benign tumors either in an adjuvant setting or in inoperable patients requiring definitive treatment, as well as in a setting to alleviate symptoms, providing excellent survival benefits. However, further prospective studies with much higher sample size are required to establish the absolute benefit and to estimate the risk of RIC, which will further direct for a better utilization of RT in treating benign tumors.

Sarcoma cell-specific radiation sensitization by titanate scrolled nanosheets: insights from physicochemical analysis and transcriptomic profiling

This study aimed to explore the potential of metal oxides such as Titanate Scrolled Nanosheets (TNs) in improving the radiosensitivity of sarcoma cell lines. Enhancing the response of cancer cells to radiation therapy is crucial, and one promising approach involves utilizing metal oxide nanoparticles. We focused on the impact of exposing two human sarcoma cell lines to both TNs and ionizing radiation (IR). Our research was prompted by previous in vitro toxicity assessments, revealing a correlation between TNs' toxicity and alterations in intracellular calcium homeostasis. A hydrothermal process using titanium dioxide powder in an alkaline solution produced the TNs. Our study quantified the intracellular content of TNs and analyzed their impact on radiation-induced responses. This assessment encompassed PIXE analysis, cell proliferation, and transcriptomic analysis. We observed that sarcoma cells internalized TNs, causing alterations in intracellular calcium homeostasis. We also found that irradiation influence intracellular calcium levels. Transcriptomic analysis revealed marked disparities in the gene expression patterns between the two sarcoma cell lines, suggesting a potential cell-line-dependent nano-sensitization to IR. These results significantly advance our comprehension of the interplay between TNs, IR, and cancer cells, promising potential enhancement of radiation therapy efficiency.

Current advances in the selection of adjuvant radiotherapy regimens for keloid

Keloid is a common benign skin tumor in the outpatient department, and patients are often accompanied by itching and pain. Since the pathogenesis is unknown, the effect of single method treatment is unsatisfactory, and therefore the recurrence rate is high. Therefore, comprehensive treatment is mostly used in clinical treatment. Adjuvant radiotherapy is currently one of the most effective treatments for keloid. After long-term clinical practice, brachytherapy and electron beam radiotherapy has increasingly become the gold standard of treatment, because brachytherapy provides more focused radiation treatment to focal tissue to significantly reduce recurrence rate, and better preserve normal tissue. With the development of new radiotherapy techniques, more options for the treatment of keloid. Currently, adjuvant radiotherapy has been widely recognized, but there is no consensus on the optimal protocol for adjuvant radiotherapy for keloids. This review provides a review of published treatment options and new radiotherapy techniques for adjuvant radiotherapy of keloids and gives a comprehensive evaluation for clinical treatment.

Assessment of Radiation-Induced Bladder and Bowel Cancer Risks after Conventionally and Hypo-Fractionated Radiotherapy for the Preoperative Management of Rectal Carcinoma

Preoperative management of rectal carcinoma can be performed by employing either conventionally or hypo-fractionated Radiotherapy (CFRT or HFRT, respectively), delivered by Intensity Modulated Radiotherapy (IMRT) or Volumetric Modulated Arc Therapy (VMAT) plans, employing 6 MV or 10 MV photon beams. This study aims to dosimetrically and radiobiologically compare all available approaches, with emphasis on the risk of radiation-induced second cancer to the bladder and bowel. Computed Tomography (CT) scans and relevant radiotherapy contours from 16 patients were anonymized and analyzed retrospectively. For each case, CFRT of 25 × 2 Gy and HFRT of 5 × 5 Gy were both considered. IMRT and VMAT plans using 6 MV and 10 MV photons were prepared. Plan optimization was performed, considering all clinically used plan quality indices and dose–volume constraints for the critical organs. Resulting dose distributions were analyzed and compared. Moreover, the Lifetime Attributable Risk (LAR) for developing radiation-induced bladder and bowel malignancies were assessed using a non-linear mechanistic model, assuming patient ages at treatment of 45, 50, 55 and 60 years. All 128 plans created were clinically acceptable. Risk of second bladder cancer reached 0.26% for HFRT (5 × 5 Gy) and 0.19% for CFRT (25 × 2 Gy) at the age of 45. Systematically higher risks were calculated for HFRT (5 × 5 Gy) as compared to CFRT (25 × 2 Gy), with 6 MV photons resulting in slightly increased LAR, as well. Similar or equal bowel cancer risks were calculated for all techniques and patient ages investigated (range 0.05–0.14%). This work contributes towards radiotherapy treatment protocol selection criteria for the preoperative irradiation of rectal carcinoma. However, more studies are needed to establish the associated radiation-induced risk of each RT protocol.

Low-dose radiation therapy for hand osteoarthritis: shaking hands again?

BACKGROUND

Hand osteoarthritis (HOA) is one of the most common causes of pain and functional disability in western countries and there is still no definitive cure. Low-dose radiation therapy (LDRT) has anti-inflammatory properties that have shown to be effective in the symptomatic relief of various degenerative musculoskeletal disorders. We designed a clinical protocol using LDRT for symptomatic HOA and present results and tolerance in the first 100 patients included.

MATERIALS AND METHODS

Between April 2015 and March 2021, 100 patients with a median age of 60 were treated. Fifty-seven patients suffering from proximal/distal interphalangeal joint pain, 40 patients with thumb arthritis, 2 patients with radiocarpal joint affection and 1 patient with metacarpophalangeal joint pain were enrolled. LDRT comprised of 6 fractions of 0.5-1 Gy on every other day up to a total dose of 3-6 Gy. Clinical response was evaluated according to the visual analog scale (VAS) for pain level and the von Pannewitz score (VPS) for joint functionality. Any patients not achieving subjective adequate pain relief after 8 weeks of treatment were offered a second identical LDRT course.

RESULTS

With a median follow-up of 10.5 months (range 7.55-12.45), 94% reported an improvement in the pain, with a significant reduction in the VAS level after 3, 6 and 12 months (p < 0.001). Sixty-three patients needed a second course of treatment at a median time interval of 12 weeks (range 9-14). The mean VAS score before treatment was 8 (range 3-10). After treatment, it was 5 (range 1-10). After 3, 6 and 12 months, the mean VAS scores were 4 (range 0-9), 3 (range 0-9) and 3.5 (range 0-9), respectively. Seventy patients reported functionality improvements after LDRT according to the von Pannewitz score. No acute or late complications were observed.

CONCLUSION

LDRT appears to be safe and useful for HOA and is associated with good rates of pain relief and functionality improvements. However, further studies are necessary to confirm these promising results.

Could pulmonary low-dose radiation therapy be an alternative treatment for patients with COVID-19 pneumonia? Preliminary results of a multicenter SEOR-GICOR nonrandomized prospective trial (IPACOVID trial)

Purpose

To evaluate the efficacy and safety of lung low-dose radiation therapy (LD-RT) for pneumonia in patients with coronavirus disease 2019 (COVID-19).

Materials and methods

Inclusion criteria comprised patients with COVID-19-related moderate–severe pneumonia warranting hospitalization with supplemental O₂ and not candidates for admission to the intensive care unit because of comorbidities or general status. All patients received single lung dose of 0.5 Gy. Respiratory and systemic inflammatory parameters were evaluated before irradiation, at 24 h and 1 week after LD-RT. Primary endpoint was increased in the ratio of arterial oxygen partial pressure (PaO₂) or the pulse oximetry saturation (SpO₂) to fractional inspired oxygen (FiO₂) ratio of at least 20% at 24 h with respect to the preirradiation value.

Results

Between June and November 2020, 36 patients with COVID-19 pneumonia and a mean age of 84 years were enrolled. Seventeen were women and 19 were men and all of them had comorbidities. All patients had bilateral pulmonary infiltrates on chest X‑ray. All patients received dexamethasone treatment. Mean SpO₂ pretreatment value was 94.28% and the SpO₂/FiO₂ ratio varied from 255 mm Hg to 283 mm Hg at 24 h and to 381 mm Hg at 1 week, respectively. In those who survived (23/36, 64%), a significant improvement was observed in the percentage of lung involvement in the CT scan at 1 week after LD-RT. No adverse effects related to radiation treatment have been reported.

Conclusions

LD-RT appears to be a feasible and safe option in a population with COVID-19 bilateral interstitial pneumonia in the presence of significant comorbidities.

Supplementary Information

The online version of this article (10.1007/s00066-021-01803-3) contains supplementary material, which is available to authorized users.

[Radiation therapy of hepatic haemangiomas: Review from a case report]

Haemangioma is the most frequent benign hepatic tumour. Haemangioma is generally asymptomatic but it can sometimes cause disabling symptoms depending on its size and location. Surgery and interventional radiology are the cornerstone of the treatment in this situation. Radiation therapy, already used with good efficacy and safety to treat hepatic malignant lesions as hepatocarcinoma and metastases, is a relevant option in case of contraindication to surgery because of multiple or very large lesions. In this context, we report the case of a patient presenting with multiple symptomatic hepatic haemangiomas, successfully treated by radiation therapy in our department. These good results justified a review of the literature to report series of patients treated in this indication and to describe the main treatment regimens used.

Risk for second bladder and rectal malignancies from cervical cancer irradiation

The objective of this study was to estimate the risk of developing second malignancies to partially in‐field organs from volumetric modulated arc therapy (VMAT) of cervical cancer and to compare the above risks with those from the conventional three‐dimensional conformal radiotherapy (3D‐CRT). Seventeen consecutive patients with uterine cervix carcinoma were selected. VMAT and 3D‐CRT plans were generated with 6 and 10 MV photons, respectively. The prescribed tumor dose was 45 Gy given in 25 fractions. Differential dose‐volume histogram data from the treatment plans were obtained for the partially in‐field organs such as bladder and rectum. These data were used to estimate the patient‐specific lifetime attributable risk (LAR) for bladder and rectal cancer induction with a non‐linear model based on a mixture of plateau and bell‐shaped dose–response relationships. The estimated risks per 10000 people were compared with the baseline risks for unexposed population. The patient‐specific rectal cancer risk estimates from VMAT were significantly lower than those from 3D‐CRT (P = 0.0144). The LARs for developing bladder malignancies from VMAT were significantly high compared to those from conventional irradiation (P = 0.0003). The mean difference between the patient‐specific LARs for radiation‐induced bladder and rectal malignancies as derived from 3D‐CRT and VMAT plans was 6.6% and 2.0%, respectively. The average LAR for developing bladder and rectal malignant diseases due to VMAT was 9.2 × 10^‐4 and 43.7 × 10^‐4, respectively. The corresponding risks following 3D‐CRT were 8.6 × 10^‐4 and 44.6 × 10^‐4. These average risks showed that pelvic irradiation increases the baseline probability for cancer induction by 12.6‐19.1%. The differences in the second cancer risks associated with the VMAT and 3D‐CRT for cervical cancer were found to be small. Both treatment techniques resulted in considerable increased probabilities for developing bladder and rectal malignancies relative to those of unirradiated population.

Lifetime radiation-induced sarcoma risk in patients subjected to IMRT or VMAT for uterine cervix carcinoma

This study was conducted to estimate the lifetime radiation-induced bone and soft tissue sarcoma risks from intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for uterine cervix carcinoma. 13 cervical cancer patients were included. The bone and soft tissue structures were defined on patients' treatment planning computed tomography (CT) scans. Both CT-based IMRT and VMAT plans with 6 MV photons delivering 45 Gy to the target site were designed for each patient. The organ equivalent dose (OED) and the lifetime attributable risk (LAR) for developing bone or soft tissue sarcoma were estimated using treatment planning data and a non-linear mechanistic model. The estimation method did not consider the survival rates following radiotherapy and the use of brachytherapy treatments. The patient-specific OEDs of the bone structure from IMRT and VMAT were 2.33-2.83 and 2.34-2.82 Gy, respectively. The corresponding values for the soft tissue structure were 1.27-1.70 and 1.32-1.73 Gy. An insignificant difference was found between the patient-specific OEDs and the directly proportional sarcoma risks (bone: P = 0.07; soft tissue: P = 0.38). The LAR for the development of a bone sarcoma varied from 0.05 to 0.16% by the patient's age during irradiation and the applied treatment delivery technique. The corresponding LAR range for radiation-induced soft-tissue sarcoma was 0.08-0.27%. The above LARs resulted in a relative risk of more than 1.20 indicating that IMRT or VMAT may lead to a considerable risk increase of developing bone or soft tissue sarcoma exceeding 20% in respect to the current incidence of these malignancies in unexposed population.

VMAT for prostate cancer with 6-MV and 10-MV photons: Impact of beam energy on treatment plan quality and model-based secondary cancer risk estimates

The aim of the present study was to examine the effect of the photon beam energy on the volumetric modulated arc therapy (VMAT) plan quality for prostate cancer and on the risk of secondary carcinogenesis. Separate VMAT plans with 6-MV and 10-MV photons were created for 11 low-risk patients with prostate cancer. The prescribed tumor dose was 70 Gy delivered in 28 fractions. The normal tissue integral dose and parameters associated with planning target volume and organs at risk were determined by the treatment planning data. A non-linear mechanistic model considering the effects of tumor dose fractionation and cell proliferation was employed for estimating the patient-specific lifetime attributable risk (LAR) for bladder and rectal cancer induction. Data from differential dose-volume histograms were used for these risk assessments. The mean values of the planning parameters from 6-MV treatment plans differed by 0.2-3.4% from those associated with irradiation using 10-MV photons. The LAR range for developing secondary bladder malignancies varied between 0.041 and 0.129% by the patient under investigation and the beam energy used. The corresponding range for the appearance of rectal malignant diseases was 0.047-0.153%. The mean percentage difference between the bladder cancer risks from VMAT with 6-MV and 10-MV photons was 2.6±2.3%. The corresponding difference for secondary rectal malignancies was 0.7±0.6%. Therefore, VMAT for prostate cancer with both 6-MV and 10-MV photons leads to clinically equivalent treatment plans and to similar secondary bladder and rectal cancer risks.

COVID-19 pneumonia treated with ultra-low doses of radiotherapy (ULTRA-COVID study): a single institution report of two cases

Introduction

Since the outbreak of coronavirus disease 2019 (COVID-19) pandemic, healthcare systems have focused their efforts into finding a treatment to avoid the fatal outcomes of severe acute respiratory syndrome due to coronavirus‑2 (SARS-CoV-2). Benefits and risks of systemic treatments remain unclear, with multiple clinical trials still ongoing. Radiotherapy could play a role in reducing the inflammatory response in the lungs and relieve life-threatening symptoms.

Methods

We designed a prospective study of Ultra-Low Doses of Therapy with Radiation Applied to COVID-19 (ULTRA-COVID) for patients who suffer pneumonia, are not candidates for invasive mechanical ventilation and show no improvement with medical therapy.

Results

We present the preliminary results of two patients diagnosed with COVID-19 pneumonia treated with ULTRA-COVID. After one radiotherapy session, significant clinical response and a good radiological response was observed in both cases, resulting in both patients being discharged from hospital in less than 2 weeks after radiation treatment.

Conclusion

Preliminary clinical and radiological results suggest a potential benefit of treating COVID-19 pneumonia with ULTRA-COVID.

ClinicalTrials.gov Identifier: NCT04394182

Low-Dose Radiation Therapy in the Management of Coronavirus Disease 2019 (COVID-19) Pneumonia (LOWRAD-Cov19): Preliminary Report

PURPOSE

Low-dose radiation therapy (LD-RT) has been shown to have an anti-inflammatory effect, and preliminary results suggest it is feasible to treat patients with coronavirus disease 2019 (COVID-19) pneumonia.

MATERIALS AND METHODS

We conducted a prospective, single-arm, phase 1/2 clinical trial enrolling patients aged ≥50 years, who were coronavirus disease 2019 (COVID-19) positive, at phase 2 or 3 with lung involvement at imaging study and oxygen requirement. Patients received 100 cGy to total lungs in a single fraction. Primary outcome was radiologic response using severity and extension score on baseline computed tomography (CT), at days 3 and 7 after LD-RT. Secondary outcomes were toxicity using Common Terminology Criteria for Adverse Events v.5.0, duration of hospitalization, blood work evolution, and oxygen requirements using SatO2/FiO2 index (SAFI), at days 3 and 7 after LD-RT.

RESULTS

Nine patients were included. Median age was 66 (interquartile range, 57-77). Severity score was stable or decreased in the third CT but was not statistically significant (P = .28); however, there were statistically significant changes in the extension score (P = .03). SAFI index significantly improved 72 hours and 1 week after LD-RT (P = .01). Inflammatory blood parameters decreased 1 week after RT compared with baseline; only lactate dehydrogenase decreased significantly (P = .04). Two patients presented grade 2 lymphopenia after RT and another (with baseline grade 3) worsened to grade 4. Overall, the median number of days of hospitalization was 59 (range, 26-151). After RT the median number of days in the hospital was 13 (range, 4-77). With a median follow-up after RT of 112 days (range, 105-150), 7 patients were discharged and 2 patients died, 1 due to sepsis and the other with severe baseline chronic obstructive pulmonary disease from COVID-19 pneumonia.

CONCLUSIONS

Our preliminary results show that LD-RT was a feasible and well-tolerated treatment, with potential clinical improvement. Randomized trials are needed to establish whether LD-RT improves severe pneumonia.

Roles of NK Cell Receptors 2B4 (CD244), CS1 (CD319), and LLT1 (CLEC2D) in Cancer

Natural killer (NK) cells play a pivotal role in the immune system, especially in the recognition and clearance of cancer cells and infected cells. Their effector function is controlled by a delicate balance between the activating and inhibitory signals. We have identified 2B4 (CD244, SLAMF4) and CS1 (CD319, SLAMF7) as NK cell receptors regulating NK cell cytotoxicity. Lectin-like transcript 1 (LLT1), a member of the C-type lectin-like domain family 2 (CLEC2D), induced IFN-γ production but did not directly regulate cytolytic activity. Interestingly, LLT1 expressed on other cells acts as a ligand for an NK cell inhibitory receptor NKRP1A (CD161) and inhibits NK cytolytic function. Extensive research has been done on novel therapies that target these receptors to increase the effector function of NK cells. The 2B4 receptor is involved in the rejection of melanoma cells in mice. Empliciti, an FDA-approved monoclonal antibody, explicitly targets the CS1 receptor and enhances the NK cell cytotoxicity against multiple myeloma cells. Our studies revealed that LLT1 is expressed on prostate cancer and triple-negative breast cancer cells and allows them to evade NK-cell-mediated killing. In this review, we describe NK cell receptors 2B4, CS1, and LLT1 and their potential in targeting cancer cells for NK-cell-mediated immunotherapy. New cancer immunotherapies like chimeric antigen receptor T (CAR-T) and NK (CAR-NK) cells are showing great promise in the treatment of cancer, and CAR cells specific to these receptors would be an attractive therapeutic option.

Low dose anti-inflammatory radiotherapy for the treatment of pneumonia by covid-19: A proposal for a multi-centric prospective trial

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Interstitial bilateral pneumonia is the main complication of severe COVID-19.

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Low-dose radiation therapy (LD-RT) has well-known anti-inflammatory effects.

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LD-RT can interfere with the hyper-inflammatory cascade associated with severe COVID-19.

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LD-RT could reduce the severity of associated cytokine release caused by COVID-19.

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This trial will evaluate efficacy of lung LD-RT for interstitial COVID-19 pneumonia.

Background

COVID-19 is a highly contagious viral infection with high morbidity that is draining health resources. The biggest complication is pneumonia, which has a serious inflammatory component, with no standardized treatment. Low-dose radiation therapy (LD-RT) is non-invasive and has anti-inflammatory effects that can interfere with the inflammatory cascade, thus reducing the severity of associated cytokine release and might be useful in the treatment of respiratory complications caused by COVID-19.

Study design and methods

This multicentric prospective clinical trial seeks to evaluate the efficacy of bilateral lung LD-RT therapy as a treatment for interstitial pneumonia in patients with COVID-19 for improving respiratory function.

This prospective study will have 2 phases: I) an exploratory phase enrolling 10 patients, which will assess the feasibility and efficacy of low-dose lung irradiation, evaluated according to an increase in the PaO2/FiO2 ratio of at least 20% at 48–72 h with respect to the pre-irradiation value. If a minimum efficiency of 30% of the patients is not achieved, the study will not be continued. II) Non-randomized comparative phase in two groups: a control group, which will only receive pharmacological treatment, and an experimental arm with pharmacological treatment and LD-RT. It will include 96 patients, the allocation will be 1: 2, that is, 32 in the control arm and 64 in the experimental arm. The primary end-point will be the efficacy of LD-RT in patients with COVID-19 pneumonia according to an improvement in PaO2/FiO2. Secondary objectives will include the safety of bilateral lung LD-RT, an improvement in the radiology image, overall mortality rates at 15 and 30 days after irradiation and characterizing anti-inflammatory mechanisms of LD-RT by measuring the level of expression of adhesion molecules, anti-inflammatory cytokines and oxidative stress mediators.

Trial registration: ClinicalTrial.gov NCT-04380818 https://clinicaltrials.gov/ct2/show/NCT04380818?term=RADIOTHERAPY&cond=COVID&draw=2&rank=4.

Secondary bladder and rectal cancer risk estimates following standard fractionated and moderately hypofractionated VMAT for prostate carcinoma

PURPOSE

To estimate the risk for bladder and rectal cancer induction due to standard fractionated (SF) and moderately hypofractionated (HF) volumetric modulated arc therapy (VMAT) for prostate carcinoma.

METHODS

Twelve patients with low or intermediate-risk of prostate cancer referred for external-beam radiotherapy were included in this study. Three computed tomography-based VMAT plans were created for each study participant. The first plan was generated by assuming patient's irradiation with SF-VMAT (78 Gy in 39 fractions). The second and third plans were created on the basis of two different HF schedules (HF-VMAT₁ : 70 Gy in 30 fractions, HF:VMAT₂ : 60 Gy in 20 fractions). Data from differential dose-volume histograms obtained by the above treatment plans were employed to calculate the organ equivalent dose (OED) of the bladder and rectum with the aid of a nonlinear model accounting for fractionation and proliferation effects. The calculated OED values were used to estimate the average lifetime attributable risk (LAR_av ) for the appearance of radiotherapy-induced secondary bladder and rectal malignancies. The lifetime risk of radiation carcinogenesis was compared with the respective organ-, and age-dependent lifetime intrinsic risk (LIR) of cancer development for unexposed males.

RESULTS

The average OED of the rectum from SF-VMAT, HF-VMAT₁ and HF-VMAT₂ for prostate cancer was 972.0, 900.2, and 815.7 cGy, respectively. The corresponding values for bladder were 73.4, 72.3, and 71.0 cGy. The LAR_av for rectal cancer induction varied from 0.06% to 0.4% by the fractionation schedule used for irradiation and by the age of the patient at the time of treatment. The corresponding risk range related to the development of secondary bladder malignancies was 0.06-0.33%. The SF-VMAT, HF-VMAT₁ and HF-VMAT₂ led to an increase of the lifetime rectal cancer risk with respect to LIR by 2.2-9.8%, 2.0-9.1% and 1.8-8.2%, respectively, depending upon the patient's age. The corresponding elevation for bladder cancer induction was up to 8.0%, 7.9% and 7.7%.

CONCLUSIONS

The use of VMAT for prostate carcinoma leads to a noteworthy increase of the lifetime risk for bladder and rectal cancer induction compared to that of unexposed people irrespective of the patient's age at the time of treatment and the applied fractionation scheme. The cancer risk data presented in this study may be taken into account by radiation oncologists and medical physicists in the selection of the optimal radiation therapy plan.

Risk of developing radiogenic cancer following photon-beam radiotherapy for Graves' orbitopathy

PURPOSE

The objective of this study was to estimate the probability for cancer development due to radiotherapy for Graves' orbitopathy with 6 MV x rays.

METHODS

Orbital irradiation was simulated with the MCNP code. The radiation dose received by 10 out-of-field organs having a strong disposition for carcinogenesis was calculated with Monte Carlo methods. These dose calculations were used to estimate the organ-dependent lifetime attributable risk (LAR) for cancer induction in 30- and 50-yr-old males and females on the basis of the linear model suggested by the BEIR-VII report. Differential dose-volume histograms derived from patients' three-dimensional (3D) radiotherapy plans were employed to determine the organ equivalent dose (OED) of the brain which was partly exposed to primary radiation. The OED and the relevant LAR for brain cancer development were assessed with the plateau, bell-shaped and mechanistic models. The radiotherapy-induced cancer risks were compared with the lifetime intrinsic risk (LIR) values for unexposed population.

RESULTS

The radiation dose range to organs excluded from the treatment volume was 0.1-91.0 mGy for a target dose of 20 Gy. These peripheral organ doses increased the LIRs for cancer development of unexposed 30- and 50-yr-old males up to 1.0% and 0.2%, respectively. The corresponding elevations after radiotherapy of females were 2.0% and 0.4%. The use of nonlinear models gave an OED range of the brain of 482.0-562.5 mGy depending upon the model used for analysis and the patient's gender. The elevation of the LIR for developing brain malignancies after radiotherapy of 30-yr-old males and females reached to 13.3% and 16.6%, respectively. The corresponding increases after orbital irradiation at the age of 50 yr were 6.7% and 8.3%.

CONCLUSIONS

The level of the LIR increase attributable to radiation therapy for GO varied widely by the organ under examination and the age and gender of the exposed subject. This study provides the required data to quantify the elevation of these baseline cancer risks following orbital irradiation.

Basics of Radiation Biology When Treating Hyperproliferative Benign Diseases

For decades, low- and moderate-dose radiation therapy (RT) has been shown to exert a beneficial therapeutic effect in a multitude of non-malignant conditions including painful degenerative muscoloskeletal and hyperproliferative disorders. Dupuytren and Ledderhose diseases are benign fibroproliferative diseases of the hand/foot with fibrotic nodules and fascial cords, which determine debilitating contractures and deformities of fingers/toes, while keloids are exuberant scar formations following burn damage, surgery, and trauma. Although RT has become an established and effective option in the management of these diseases, experimental studies to illustrate cellular composites and factors involved remain to be elucidated. More recent findings, however, indicate the involvement of radiation-sensitive targets like mitotic fibroblasts/myofibroblasts as well as inflammatory cells. Radiation-related molecular mechanisms affecting these target cells include the production of free radicals to hamper proliferative activity and interference with growth factors and cytokines. Moreover, an impairment of activated immune cells involved in both myofibroblast proliferative and inflammatory processes may further contribute to the clinical effects. We here aim at briefly describing mechanisms contributing to a modulation of proliferative and inflammatory processes and to summarize current concepts of treating hyperproliferative diseases by low and moderate doses of ionizing radiation.