Radiation pneumonitis successfully treated with inhaled corticosteroids

The role of corticosteroids in the palliation of dyspnea in cancer patients: an evidence-based review

PURPOSE OF REVIEW

To provide an evidence-based review on the use of corticosteroids for dyspnea in cancer patients.

RECENT FINDINGS

Corticosteroids are commonly used for palliation of dyspnea; however, there is wide variation in how they are prescribed due to the paucity of high-quality evidence. Some clinicians would offer corticosteroids routinely regardless of the causes of dyspnea, while others would only prescribe corticosteroids selectively for specific indications, such as lymphangitic carcinomatosis, upper airway obstruction, superior vena cava obstruction, and cancer treatment-induced pneumonitis. Few mechanistic studies have been conducted to support the use of corticosteroids in cancer patients. Two double-blind, placebo-controlled randomized trials have examined the routine use of high-dose dexamethasone for dyspnea in cancer patients. A pilot study suggested some benefits, but the larger confirmatory trial revealed no improvement compared to the placebo and significantly more adverse events. The selective use of corticosteroids use is only based on observational studies such as case series.

SUMMARY

The unfavorable risk:benefit ratio of high-dose dexamethasone suggests that it should not be routinely prescribed for dyspnea in cancer patients. More research is needed to assess the selective use of corticosteroids and identify patients most likely be benefit from corticosteroid use.

A human lung alveolus-on-a-chip model of acute radiation-induced lung injury

Acute exposure to high-dose gamma radiation due to radiological disasters or cancer radiotherapy can result in radiation-induced lung injury (RILI), characterized by acute pneumonitis and subsequent lung fibrosis. A microfluidic organ-on-a-chip lined by human lung alveolar epithelium interfaced with pulmonary endothelium (Lung Alveolus Chip) is used to model acute RILI in vitro. Both lung epithelium and endothelium exhibit DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6 h of radiation exposure, although greater damage is observed in the endothelium. The radiation dose sensitivity observed on-chip is more like the human lung than animal preclinical models. The Alveolus Chip is also used to evaluate the potential ability of two drugs - lovastatin and prednisolone - to suppress the effects of acute RILI. These data demonstrate that the Lung Alveolus Chip provides a human relevant alternative for studying the molecular basis of acute RILI and may be useful for evaluation of new radiation countermeasure therapeutics.

Radiation-Induced Lung Injury-Current Perspectives and Management

Radiotherapy plays an important role in the treatment of localized primary malignancies involving the chest wall or intrathoracic malignancies. Secondary effects of radiotherapy on the lung result in radiation-induced lung disease. The phases of lung injury from radiation range from acute pneumonitis to chronic pulmonary fibrosis. Radiation pneumonitis is a clinical diagnosis based on the history of radiation, imaging findings, and the presence of classic symptoms after exclusion of infection, pulmonary embolism, heart failure, drug-induced pneumonitis, and progression of the primary tumor. Computed tomography (CT) is the preferred imaging modality as it provides a better picture of parenchymal changes. Lung biopsy is rarely required for the diagnosis. Treatment is necessary only for symptomatic patients. Mild symptoms can be treated with inhaled steroids while subacute to moderate symptoms with impaired lung function require oral corticosteroids. Patients who do not tolerate or are refractory to steroids can be considered for treatment with immunosuppressive agents such as azathioprine and cyclosporine. Improvements in radiation technique, as well as early diagnosis and appropriate treatment with high-dose steroids, will lead to lower rates of pneumonitis and an overall good prognosis.

Dynamic changes in T-cell subsets and C-reactive protein after radiation therapy in lung cancer patients and correlation with symptomatic radiation pneumonitis treated with steroid therapy

Objectives

To investigate relationships among serum T-cell subsets, CRP, levels and radiation pneumonitis (RP) in lung cancer patients receiving radiotherapy.

Methods

A case-control study with frequency matching was carried out. The case group comprised 36 lung cancer patients who had developed grade ≥2 RP after thoracic radiotherapy. The control group was 36 patients with lung cancer without RP. Patients in the case group received steroid therapy for 1 month after diagnosis of RP and were followed up for 3 months. T-cell subsets, CRP, and pulmonary function were detected at three time points (onset of RP and 1 and 3 months after diagnosis). Data for the control group were collected 3 months after radiotherapy. Treatment effectiveness was evaluated at 1 and 3 months after diagnosis of RP.

Results

Of the 36 patients in the case group, three with grade5 RP died from respiratory failure. The other 33 cases had all improved with steroid therapy at 3 months after RP diagnosis. In these 33, CD3⁺T-cell quantity, CD4⁺T-cell quantity, and of CD4⁺:CD8⁺ ratio in T-cell subsets decreased significantly and CRP increased (P<0.05) at the onset of RP compared with the control group. After steroid therapy, CD4⁺T-cell quantity increased significantly compared to before treatment. The same change was seen in CD4⁺:CD8⁺ ratio, whereas CRP levels decreased obviously, with treatment effectiveness improved. In addition, with the damage level of RP increased, CD4⁺ T -cell quantity decreased obviously and CRP levels increased accordingly at the onset of RP (P<0.05).

Conclusion

T-cell subsets and CRP may become effective immunological biomarkers for predicting damage from RP and evaluating treatment effectivesness of steroid therapy.

Radiation-induced lung injury: impact on macrophage dysregulation and lipid alteration - a review

Lung cancer continues to be the leading cause of cancer deaths and more than one million lung cancer patients will die every year worldwide. Radiotherapy (RT) plays an important role in lung cancer treatment, but the side effects of RT are pneumonitis and pulmonary fibrosis. RT-induced lung injury causes damage to alveolar-epithelial cells and vascular endothelial cells. Macrophages play an important role in the development of pulmonary fibrosis despite its role in immune response. These injury activated macrophages develop into classically activated M1 macrophage or alternative activated M2 macrophage. It secretes cytokines, interleukins, interferons, and nitric oxide. Several pro-inflammatory lipids and pro-apoptotic proteins cause lipotoxicity such as LDL, FC, DAG, and FFA. The overall findings in this review conclude the importance of macrophages in inducing toxic/inflammatory effects during RT of lung cancer, which is clinically vital to treat the radiation-induced fibrosis.

Managing the oncologic patient with suspected pneumonia in the intensive care unit

INTRODUCTION

Solid cancer patients are frequently admitted in intensive care units for critical events. Improving survival rates in this setting is considered an achievable goal today. Respiratory failure is the main reason for admission, representing a primary target for research.

AREAS COVERED

This review presents a diagnostic and therapeutic algorithm for pneumonia and other severe respiratory events in the solid cancer population. It aims to increase awareness of the risk factors and the different etiologies in this changing scenario in which neutropenia no longer seems to be a decisive factor in poor outcome. Bacterial pneumonia is the leading cause, but opportunistic diseases and non-infectious etiologies, especially unexpected adverse effects of radiation, biological drugs and monoclonal antibodies, are becoming increasingly frequent. Options for respiratory support and diagnostics are discussed and indications for antibiotics in the management of pneumonia are detailed. Expert commentary: Prompt initiation of critical care to facilitate optimal decision-making in the management of respiratory failure, early etiological assessment and appropriate antibiotic therapy are cornerstones in management of severe pneumonia in oncologic patients.

Detection of regional radiation-induced lung injury using hyperpolarized 129Xe chemical shift imaging in a rat model involving partial lung irradiation: Proof-of-concept demonstration

PURPOSE

The purpose of this work was to use magnetic resonance imaging (MRI) of hyperpolarized (HP) 129Xe dissolved in pulmonary tissue (PT) and red blood cells (RBCs) to detect regional changes to PT structure and perfusion in a partial-lung rat model of radiation-induced lung injury and compare with histology.

METHODS AND MATERIALS

The right medial region of the lungs of 6 Sprague-Dawley rats was irradiated (20 Gy, single-fraction). A second nonirradiated cohort served as the control group. Imaging was performed 4 weeks after irradiation to quantify intensity and heterogeneity of PT and RBC 129Xe signals. Imaging findings were correlated with measures of PT and RBC distribution.

RESULTS

Asymmetric (right vs left) changes in 129Xe signal intensity and heterogeneity were observed in the irradiated cohort but were not seen in the control group. PT signal was observed to increase in intensity and heterogeneity and RBC signal was observed to increase in heterogeneity in the irradiated right lungs, consistent with histology.

CONCLUSION

Regional changes to PT and RBC 129Xe signals are detectable 4 weeks following partial-lung irradiation in rats.

IPW-5371 Proves Effective as a Radiation Countermeasure by Mitigating Radiation-Induced Late Effects

There is an ongoing and significant need for radiation countermeasures to reduce morbidities and mortalities associated with exposure of the heart and lungs from a radiological or nuclear incidents. Radiation-induced late effects occur months to years after exposure, stemming from significant tissue damage and remodeling, resulting in fibrosis and loss of function. TGF-β is reported to play a role in both pulmonary and cardiac fibrosis. We investigated the ability of a small molecule TGF-β receptor 1 inhibitor, IPW-5371, to mitigate the effects of thoracic irradiation in C57L/J mice, a murine model that most closely resembles that observed in humans in the induction of fibrosis and dose response. To simulate a radiological event, radiation was administered in two doses: 5 Gy total-body irradiation (eliciting a whole-body response) and immediately after that, a thoracic "top-up" of 6.5 Gy irradiation, for a total dose of 11.5 Gy to the thorax. IPW-5371 was administered once daily, orally, starting 24 h postirradiation for 6 or 20 weeks at a dose of 10 mg/kg or 30 mg/kg. Animals were monitored for a period of 180 days for survival, and cardiopulmonary injury was assessed by echocardiography, breathing rate and arterial oxygen saturation. Exposure of the thorax (11.5 Gy) induced both pulmonary and cardiac injury, resulting in a reduced life span with median survival of 135 days. IPW-5371 treatment for 6 weeks, at both 10 mg/kg and 30 mg/kg, delayed disease onset and mortality, with median survival of 165 days. Twenty weeks of IPW-5371 treatment at 30 mg/kg preserved arterial O₂ saturation and cardiac contractile reserve and resulted in significant decreases in breathing frequency and cardiac and pulmonary fibrosis. This led to dramatic improvement in survival compared to the irradiated, vehicle-treated group (P < 0.001), and was statistically insignificant from the nonirradiated group. We observed that IPW-5371 treatment resulted in decreased pSmad3 tissue levels, confirming the effect of IPW-5371 on TGF-β signaling. These results demonstrate that IPW-5371 represents a potentially promising radiation countermeasure for the treatment of radiation-induced late effects.

Radiation Pneumonitis

Radiation-induced lung injury is a well-known complication of thoracic radiation for patients with breast, lung, thymic, and esophageal malignancies, and mediastinal lymphomas. Improvements in radiation technique, as well as the understanding of the pathophysiology of radiation injury, have led to lower rates of pneumonitis and improved symptom control. Here, the authors provide an overview of the pathophysiology, diagnosis, and management of patients with radiation pneumonitis as a complication of treatment of chest malignancies.

18FDG PET-CT standardized uptake value for the prediction of radiation pneumonitis in patients with lung cancer receiving radiotherapy

The present study aimed to determine if the standardized uptake value (SUV) determined with ¹⁸F-FDG PET-CT can be used to predict radiation pneumonitis (RP) in lung cancer patients who receive radiotherapy. A total of 40 patients with non-small cell lung cancer received ¹⁸F-FDG PET-CT examinations prior to and following radiotherapy. The average SUV of lung tissue prior to and following radiation were measured at differing radiation doses. SUV differences between patients with and without RP, and the SUV ratio of the irradiated lung tissues compared with that of non-irradiated lung tissues (L/B) were compared. There were no differences in the mean SUV between the RP and no RP groups prior to radiotherapy. There were also no significant differences in the mean SUV of lung tissue within groups or between the no RP and RP groups with radiation doses of <5 Gy, 5 to ≤14.9 Gy and 15 to ≤34.9 Gy (all P>0.05) following radiotherapy. There were, however, statistically significant differences in the mean SUV of lung tissue within groups or between the no RP and RP groups with doses of ≥60 Gy prior to therapy and 35 to ≤59.9 Gy and ≥60 Gy following therapy (all P<0.05). When the L/B ratio was ≥3, the incidence of RP was 50%, and when the L/B ratio was ≥2.5 the incidence was 40.7%. When the L/B ratio was <2, there were no cases of RP. In conclusion, the present study indicates that ¹⁸F-FDG PET-CT can be used to predict RP by L/B ratio.

The extent of irradiation-induced long-term visceral organ damage depends on cranial/brain exposure

In case of high-dose radiation exposure, mechanisms controlling late visceral organ damage are still not completely understood and may involve the central nervous system. To investigate the influence of cranial/brain irradiation on late visceral organ damage in case of high-dose exposure, Wistar rats were irradiated at 12 Gy, with either the head and fore limbs or the two hind limbs protected behind a lead wall (head- and hind limbs-protected respectively), which allows long-term survival thanks to bone marrow protection. Although hind limbs- and head-protected irradiated rats exhibited similar hematopoietic and spleen reconstitution, a late body weight loss was observed in hind limbs-protected rats only. Histological analysis performed at this time revealed that late damages to liver, kidney and ileum were attenuated in rats with head exposed when compared to animals whose head was protected. Plasma measurements of inflammation biomarkers (haptoglobin and the chemokine CXCL1) suggest that the attenuated organ damage in hind limbs-protected rats may be in part related to reduced acute and chronic inflammation. Altogether our results demonstrate the influence of cranial/brain exposure in the onset of organ damage.

Animal models and medical countermeasures development for radiation-induced lung damage: report from an NIAID Workshop

Since 9/11, there have been concerns that terrorists may detonate a radiological or nuclear device in an American city. Aside from several decorporation and blocking agents for use against internal radionuclide contamination, there are currently no medications within the Strategic National Stockpile that are approved to treat the immediate or delayed complications resulting from accidental exposure to radiation. Although the majority of research attention has focused on developing countermeasures that target the bone marrow and gastrointestinal tract, since they represent the most acutely radiosensitive organs, individuals who survive early radiation syndromes will likely suffer late effects in the months that follow. Of particular concern are the delayed effects seen in the lung that play a major role in late mortality seen in radiation-exposed patients and accident victims. To address these concerns, the National Institute of Allergy and Infectious Diseases convened a workshop to discuss pulmonary model development, mechanisms of radiation-induced lung injury, targets for medical countermeasures development, and end points to evaluate treatment efficacy. Other topics covered included guidance on the challenges of developing and licensing drugs and treatments specific to a radiation lung damage indication. This report reviews the data presented, as well as key points from the ensuing discussion.

Development and licensure of medical countermeasures to treat lung damage resulting from a radiological or nuclear incident

Due to the ever-present threat of a radiological or nuclear accident or attack, the National Institute of Allergy and Infectious Diseases, Radiation Medical Countermeasures Program was initiated in 2004. Since that time, the Program has funded research to establish small and large animal models for radiation damage, as well as the development of approaches to mitigate/treat normal tissue damage following radiation exposure. Because some of these exposures may be high-dose, and yet heterogeneous, the expectation is that some victims will survive initial acute radiation syndromes (e.g. hematopoietic and gastrointestinal), but then suffer from potentially lethal lung complications. For this reason, efforts have concentrated on the development of animal models of lung irradiation damage that mimic expected exposure scenarios, as well as drugs to treat radiation-induced late lung sequelae including pneumonitis and fibrosis. Approaches targeting several pathways are under study, with the eventual goal of licensure by the United States Food and Drug Administration for government stockpiling. This Commentary outlines the status of countermeasure development in this area and provides information on the specifics of licensure requirements, as well as guidance and a discussion of challenges involved in developing and licensing drugs and treatments specific to a radiation lung damage indication.

After the bomb drops: a new look at radiation-induced multiple organ dysfunction syndrome (MODS)

PURPOSE

There is increasing concern that, since the Cold War era, there has been little progress regarding the availability of medical countermeasures in the event of either a radiological or nuclear incident. Fortunately, since much is known about the acute consequences that are likely to be experienced by an exposed population, the probability of survival from the immediate hematological crises after total body irradiation (TBI) has improved in recent years. Therefore focus has begun to shift towards later down-stream effects, seen in such organs as the gastrointestinal tract (GI), skin, and lung. However, the mechanisms underlying therapy-related normal tissue late effects, resulting from localised irradiation, have remained somewhat elusive and even less is known about the development of the delayed syndrome seen in the context of whole body exposures, when it is likely that systemic perturbations may alter tissue microenvironments and homeostasis.

CONCLUSIONS

The sequence of organ failures observed after near-lethal TBI doses are similar in many ways to that of multiple organ dysfunction syndrome (MODS), leading to multiple organ failure (MOF). In this review, we compare the mechanistic pathways that underlie both MODS and delayed normal tissue effects since these may impact on strategies to identify radiation countermeasures.

Radiation pneumonitis and pulmonary fibrosis in non-small-cell lung cancer: pulmonary function, prediction, and prevention

Although radiotherapy improves locoregional control and survival in patients with non-small-cell lung cancer, radiation pneumonitis is a common treatment-related toxicity. Many pulmonary function tests are not significantly altered by pulmonary toxicity of irradiation, but reductions in D(L(CO)), the diffusing capacity of carbon monoxide, are more commonly associated with pneumonitis. Several patient-specific factors (e.g. age, smoking history, tumor location, performance score, gender) and treatment-specific factors (e.g. chemotherapy regimen and dose) have been proposed as potential predictors of the risk of radiation pneumonitis, but these have not been consistently demonstrated across different studies. The risk of radiation pneumonitis also seems to increase as the cumulative dose of radiation to normal lung tissue increases, as measured by dose-volume histograms. However, controversy persists about which dosimetric parameter optimally predicts the risk of radiation pneumonitis, and whether the volume of lung or the dose of radiation is more important. Radiation oncologists ought to consider these dosimetric factors when designing radiation treatment plans for all patients who receive thoracic radiotherapy. Newer radiotherapy techniques and technologies may reduce the exposure of normal lung to irradiation. Several medications have also been evaluated for their ability to reduce radiation pneumonitis in animals and humans, including corticosteroids, amifostine, ACE inhibitors or angiotensin II type 1 receptor blockers, pentoxifylline, melatonin, carvedilol, and manganese superoxide dismutase-plasmid/liposome. Additional research is warranted to determine the efficacy of these medications and identify nonpharmacologic strategies to predict and prevent radiation pneumonitis.