Future directions in palliative thoracic radiotherapy
Recent systematic review, practice guidelines, and consensus statements have summarized the known clinical trial information with regards to the appropriate use of external-beam radiation, brachytherapy, and concurrent chemotherapy (with external-beam radiotherapy) in the palliation of chest symptoms with thoracic radiotherapy. The purpose of this review is to describe our present knowledge with regards to palliative thoracic radiotherapeutic maneuvers and to identify potential areas for future research inquiry consistent with current knowledge gaps.
Two systematic reviews, one practice guideline, and one consensus statement based on published prospective clinical trials have demonstrated that palliative thoracic radiotherapy is an effective modality both in terms of symptom palliation and other important cancer outcomes. Evolving areas for future scientific inquiry include the role of advanced technologies such as intensity-modulated radiation therapy and image-guided radiation therapy, economic analyses as well as the creation of a common palliative endpoint that can be used for future clinical trials.
Robust clinical trial information and high-level knowledge-translation documents currently exist to guide radiotherapy practitioners to provide standard-of-care treatment for thoracic palliative scenarios.
Available from: Alexander Louie
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Treatment of thoracic symptoms related to lung cancer with palliative radiotherapy is routinely performed in conjunction with radiation oncology practice. Various clinical trials, meta-analyses, practice guidelines, consensus statements, and Cochrane reviews have been conducted on different questions related to palliative thoracic radiotherapy considerations including: patient selection, external-beam radiotherapy dose fractionation, endobronchial brachytherapy, and chemotherapy.
Novel radiotherapy technologies such as stereotactic ablative radiotherapy may allow new populations to benefit from radiotherapy. These new populations include: early stage lung cancer patients not fit for surgery that previously would be treated with best supportive care or palliative approaches and the treatment of oligometastatic lung metastases.
The goal of this narrative review is: (1) to review the foundations of what has already been established in palliative thoracic radiotherapy, with a focus on published clinical trials, (2) to review and discuss emerging data and trends in radiotherapeutic options for patients with advanced thoracic malignancies, with a focus on both clinical trials and other forms comparative-effectiveness research, and (3) to discuss active areas of research and future directions for research in this challenging patient population.
09/2012; 1(3). DOI:10.1007/s13566-012-0042-y
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ABSTRACT: Metallic airway stents are often used in the management of central airway malignancies. The presence of a metallic foreign body may affect radiation dose in tissue. We studied the effect of a metallic airway stent on radiation dose delivery in a phantom and an in vivo porcine model.
A metallic tracheal stent was fitted onto a support in a water phantom. Point dosimeters were positioned in the phantom around the support and the stent. Irradiation was then performed on a linear accelerator with and without the stent. Metallic tracheal stents were deployed in the trachea of three pigs. Dosimeters were implanted in the tissues near (Group 1) and away (Group 2) from the stent. The pigs were then irradiated, and the dose perturbation factor was calculated by comparing the actual dose detected by the dosimeters versus the planned dose.
The difference in the dose detected by the dosimeters and the planned dose ranged from 1.8% to 6.1% for the phantom with the stent and 0%-5.3% for the phantom without the stent. These values were largely within the manufacturer's specified error of 5%. No significant difference was observed in the dose perturbation factor for Group 1 and Group 2 dosimeters (0.836 ± 0.058 versus 0.877 ± 0.088, P = 0.220) in all the three pigs.
Metallic airway stents do not significantly affect radiation dose in the airway and surrounding tissues in a phantom and porcine model. Radiation treatment planning systems can account for the presence of the stent. External beam radiation can be delivered without concern for significant dose perturbation.
Journal of Surgical Research 01/2014; 189(1). DOI:10.1016/j.jss.2014.01.013 · 1.94 Impact Factor
Available from: PubMed Central
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ABSTRACT: The C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me), one of the synthetic triterpenoids, has been found to have potent anti-inflammatory and anticancer properties in vitro and in vivo. However, its usefulness in mitigating radiation-induced lung injury (RILI), including radiation-induced lung inflammation and fibrosis, has not been tested. The aim of this study was to explore the therapeutic effect of CDDO-Me on RILI in mice and the underlying mechanisms. Herein, we found that administration of CDDO-Me improved the histopathological score, reduced the number of inflammatory cells and concentrations of total protein in bronchoalveolar lavage fluid, suppressed secretion and expression of proinflammatory cytokines, including transforming growth factor-β and interleukin-6, elevated expression of the anti-inflammatory cytokine interleukin-10, and downregulated the mRNA level of profibrotic genes, including for fibronectin, α-smooth muscle actin, and collagen I. CDDO-Me attenuated radiation-induced lung inflammation. CDDO-Me also decreased the Masson's trichrome stain score, hydroxyproline content, and mRNA level of profibrotic genes, and blocked radiation-induced collagen accumulation and fibrosis. Collectively, these findings suggest that CDDO-Me ameliorates radiation-induced lung inflammation and fibrosis, and this synthetic triterpenoid is a promising novel therapeutic agent for RILI. Further mechanistic, efficacy, and safety studies are warranted to elucidate the role of CDDO-Me in the management of RILI.
Drug Design, Development and Therapy 06/2015; 9:3163-78. DOI:10.2147/DDDT.S80958 · 3.03 Impact Factor
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