Risk factors for severe radiation pneumonitis in lung cancer.
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BACKGROUND: Risk factors for severe radiation pneumonitis, which often spreads beyond treatment portals and may even be bilateral, have not been fully investigated. The purpose of this study was to identify important factors associated with severe radiation pneumonitis. METHODS: 111 cases of primary lung cancer, treated with radiotherapy or chemoradiotherapy, were retrospectively analyzed. RESULTS: Severe radiation pneumonitis occurred in 17 cases (15.3%). The ratio of interstitial change in lungs before radiotherapy and radiotherapy to the contralateral mediastinum with > 40 Gy in the radiation pneumonitis group (RP group) was significantly higher than in patients without radiation pneumonitis (control group) (47.1% vs 5.3%; P < 0.001 and 58.8% vs 27.7%; P = 0.037, respectively). Using logistic regression analysis, interstitial changes before radiotherapy and radiotherapy to the contralateral mediastinum of > 40 Gy were significant risk factors associated with severe radiation pneumonitis. CONCLUSIONS: These data suggest that pre-existing interstitial changes detected by chest radiography or computed tomography and radiotherapy to the contralateral mediastinum (> 40 Gy) may predict the development of severe radiation pneumonitis. (+info)
Bilateral lymphocytic alveolitis: a common reaction after unilateral thoracic irradiation.
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The main aim of the present study was to assess the early diagnostic value of bronchoalveolar lavage (BAL) in radiation-induced lung injury in patients with breast carcinoma. Twenty-six females receiving postoperative radiotherapy for breast cancer were evaluated before and 0, 15, 30, 60, and 180 days after radiotherapy. History, physical examination, chest radiographs, and pulmonary function tests were obtained. BAL, including lymphocyte subsets analysis, was limited to the second evaluation after radiotherapy. A group of 21 healthy females were used as control. Findings after radiotherapy in asymptomatic patients were compared with findings in a group of patients with radiation pneumonitis. Irradiated patients showed a significantly (p<0.01) greater percentage (29.5+/-15.7%) of BAL lymphocytes than controls (6.2+/-3.3%). No statistical differences existed in BAL findings between the irradiated and unirradiated sides of the chest. Percentages of BAL lymphocytes did not differ significantly between patients who developed subsequent pneumonitis (24.5+/-13.5%) and those who did not develop pneumonitis (32.8+/-16.5%). Patients with pneumonitis at the time of BAL had significantly higher (p<0.05) alveolar CD4 subset cells (24.8+/-10.2%) than asymptomatic patients (15.2+/-8.9%). Maximal reductions in total lung capacity (p<0.01), and residual volume (p<0.05) occurred 60 days after irradiation. The early lymphocytic alveolitis induced by unilateral thoracic radiotherapy in most patients with breast cancer is always bilateral and does not predict the subsequent development of radiological evidence of pneumonitis. (+info)
Soluble intercellular adhesion molecule-1 as an early detection marker for radiation pneumonitis.
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To investigate the role of intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of radiation pneumonitis and to determine whether the measurement of soluble ICAM-1 (sICAM-1) levels is useful for predicting the onset of pneumonitis, the levels of sICAM-1 were measured in serum and bronchoalveolar lavage (BAL) fluids from patients with lung malignancy who received radiotherapy. A total of 30 patients were irradiated with a total dose of approximately 60 Gy. Blood samples were taken before, midway and after radiotherapy. BAL was also performed before and after radiotherapy in seven cases. The sICAM-1 concentration was measured using an enzyme-linked immunosorbent assay kit with two different monoclonal antibodies. Twelve out of 30 cases developed radiation pneumonitis (pneumonitis group), and the other cases did not (nonpneumonitis group). Serum levels of sICAM-1 after radiotherapy were significantly elevated in the pneumonitis group, but not in the nonpneumonitis group. In some of the cases in the pneumonitis group, sICAM-1 levels began to increase at an early phase of irradiation. In one case of pneumonitis in which BAL was performed, the total cell count and the number of lymphocytes increased markedly, as did the level of sICAM-1 in BAL fluid. These findings suggest that intercellular adhesion molecule-1 may play an important role in the development of radiation pneumonitis and that soluble intercellular adhesion molecule-1 may be a useful marker for the early detection of radiation pneumonitis. (+info)
Noninfectious lung disease in the immunocompromised host.
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Patients with compromised immune function suffer a wide variety of lung insults. Infections are the most common causes of both acute and chronic lung diseases, but many noninfectious conditions affect the lungs. The clinical presentation of these noninfectious conditions often mimic infections, thus causing diagnostic dilemmas. The spectrum of noninfectious lung injury and response in the immunosuppressed host includes interstitial edema, interstitial fibrosis, diffuse idiopathic pneumonia, acute respiratory distress syndrome, and obliterative bronchiolitis. Alveolar hemorrhage may complicate any of these conditions. Lung injury in the immunosuppressed host is associated with a diversity of etiologies: sepsis, irradiation, graft rejection, reperfusion injury, graft-versus-host disease, and chemotherapeutic agents and other drug reactions. These injuries most often present as diffuse pulmonary infiltrates on chest radiograph. Establishing a specific diagnosis and etiology for the injury is often problematic. From a pragmatic standpoint, excluding the possibility of infection is the principal aim of diagnostic testing. (+info)
The lung as a target organ in patients with hematologic disorders.
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The lung is one of the organs most severely affected by complications during the course of hematologic disorders. In the last years an impressive amount of progress has been made in clarifying the pathogenesis of lung diseases, particularly those occurring in conditions of severe immunosuppression such as bone marrow transplantion, acquired immunodeficiency syndrome or leukemia. Peculiar anatomical characteristics render the lung parenchyma highly susceptible to infections, but the clinical outcome is due not only to the injury induced by the pathogens but also to their interactions with inflammatory cells and particularly to the effects of a wide network of secreted cytokines. Polymorphonuclear cells, macrophages, lymphocytes and structural pulmonary cells (epithelial cells, interstitial cells) generate a variety of cytokines and growth factors which, in turn, may be responsible for the majority of the clinical effects in response to infections, such as those of Pneumocystis carinii and cytomegalovirus, but also to certain drugs or to radiation. The pathogenesis of graft-versus-host disease (GVHD) is still poorly understood, but animal models seem to demonstrate the involvement of a number of cytokines and growth factors, together with toxic effects induced by conditioning regimens. (+info)
The role of anti-epithelial cell antibodies in the pathogenesis of bilateral radiation pneumonitis caused by unilateral thoracic irradiation.
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Two cases of bilateral radiation pneumonitis associated with unilateral thoracic irradiation against lung cancer are described. Both patients died of respiratory failure and autopsy was performed. Histologically, bilateral diffuse alveolar damage was demonstrated in both cases, associated with marked organization of hyaline membrane in one case (case 1). In addition, numerous hyperplastic type II pneumocytes which strongly expressed cytokeratins 8, 18 and 19 were observed. In both patients' sera, antibodies against cytokeratin 8, 18 and 19 were demonstrated by a Western immunoblot. The possible association between autoantibodies to cytokeratins and diffuse alveolar damage observed in patients with bilateral radiation pneumonitis are discussed. (+info)
Experimental radiosurgery simulations using a theoretical model of cerebral arteriovenous malformations.
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BACKGROUND AND PURPOSE: A novel biomathematical arteriovenous malformation (AVM) model based on electric network analysis was used to investigate theoretically the potential role of intranidal hemodynamic perturbations in elevating the risk of rupture after simulated brain AVM radiosurgery. METHODS: The effects of radiation on 28 interconnected plexiform and fistulous AVM nidus vessels were simulated by predefined random or stepwise occlusion. Electric circuit analysis revealed the changes in intranidal flow, pressure, and risk of rupture at intervals of 3 months during a 3-year latency period after simulated partial/complete irradiation of the nidus using doses <25 and >/=25 Gy. An expression for risk of rupture was derived on the basis of the functional distribution of the critical radii of component vessels. The theoretical effects of radiation were also tested on AVM nidus vessels with progressively increasing elastic modulus (E:) and wall thickness during the latency period, simulating their eventual fibrosis. RESULTS: In an AVM with E=5. 0x10(4) dyne/cm(2), 4 (14.3%) of a total 28 sets of AVM radiosurgery simulations revealed theoretical nidus rupture (risk of rupture >/=100%). Three of these were associated with partial nidus coverage and 1 with complete treatment. All ruptures occurred after random occlusion of nidus vessels in AVMs receiving low-dose radiosurgery. Intranidal hemodynamic perturbations were observed in all cases of AVM rupture; the occlusion of a fistulous component resulted in intranidal rerouting of flow and escalation of the intravascular pressure in adjacent plexiform components. Risk of rupture was found to correlate with nidus vessel wall strength: a low E: of 1.9x10(4) dyne/cm(2) resulted in a 92.8% incidence of AVM rupture, whereas a higher E: of 7.0x10(4) dyne/cm(2) resulted in only a 3.6% incidence of AVM rupture. A dramatic reduction in rupture incidence was observed when increasing fibrosis of the nidus was modeled during the latency period. CONCLUSIONS: It was found that the theoretical occurrence of AVM hemorrhage after radiosurgery was low, particularly when radiation-induced fibrosis of nidus vessels was considered. When rupture does occur, it would appear from a theoretical standpoint that the occlusion of intranidal fistulas or larger-caliber plexiform vessels could be a significant culprit in the generation of critical intranidal hemodynamic surges resulting in nidus rupture. The described AVM model should serve as a useful research tool for further theoretical investigations of cerebral AVM radiosurgery and its hemodynamic sequelae. (+info)
Ionizing radiation enhances matrix metalloproteinase-2 production in human lung epithelial cells.
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Radiation pneumonitis is a major complication of radiation therapy. However, the detailed cellular mechanisms have not been clearly defined. Based on the recognition that basement membrane disruption occurs in acute lung injury and that matrix metalloproteinase (MMP)-2 can degrade type IV collagen, one of the major components of the basement membrane, we hypothesized that ionizing radiation would modulate MMP-2 production in human lung epithelial cells. To evaluate this, the modulation of MMP-2 with irradiation was investigated in normal human bronchial epithelial cells as well as in A549 cells. We measured the activity of MMP-2 in the conditioned medium with zymography and the MMP-2 mRNA level with RT-PCR. Both of these cells constitutively expressed 72-kDa gelatinolytic activity, corresponding to MMP-2, and exposure to radiation increased this activity. Consistent with the data of zymography, ionizing radiation increased the level of MMP-2 mRNA. This radiation-induced increase in MMP-2 expression was mediated via p53 because the p53 antisense oligonucleotide abolished the increase in MMP-2 activity as well as the accumulation of p53 after irradiation in A549 cells. These results indicate that MMP-2 expression by human lung epithelial cells is involved in radiation-induced lung injury. (+info)