Normal-tissue toxicities of thoracic radiation therapy: esophagus, lung, and spinal cord as organs at risk.

The evolution of therapeutic approaches for lung cancer illustrates the trend for treatment intensification, with hopes that dose-intense chemotherapy regimens, higher radiation therapy (RT) doses, or novel fractionation schemes will result in prolongation of survival. Current chemotherapy- and RT-intense regimens may not be intensified further without addressing dose-limiting toxicities such as esophagitis. It is important to understand factors pre-disposing to esophagitis so that strategies to minimize its severity can be investigated. Pulmonary complications such as pneumonitis and fibrosis from RT (with or without chemotherapy) are dose and volume dependent. Methods to better identify the target tissues and improved RT-delivery systems may facilitate increasing target doses or reducing doses to adjacent normal tissues. Biologic predictors may allow clinicians in the future to individualize RT treatment based on a patient's toxicity risk profile. Radiation myelopathy is still the most feared radiation complication of lung cancer treatment. The authors address the known parameters that influence the incidence of thoracic radiation myelopathy and the putative factors that could be considered when a clinician may be required to push the spinal cord dose in favor of tumor control.

The role of palliative thoracic radiotherapy in non-small cell lung cancer.

Non-small cell lung cancer is the most common cause of cancer death in both males and females. Despite this high incidence and mortality, comparatively little research has addressed the palliative treatment of thoracic symptoms. Until recently, information regarding the indications and effectiveness of radiation in this setting was obtained from retrospective reviews of single institutional experiences. More recently, three major randomized trials from the UK Medical Research Council (1991, 1992, 1994) have addressed the use of external beam radiation in randomized comparisons of different dose and fractionation strategies for patients with non-small cell lung cancer and symptoms due to intra-thoracic tumor. These studies show that shorter fractionation schemes provide equivalent palliation and essentially equivalent survival in the patient groups studied. Moreover, they provide estimates of the probability of successful palliation of common symptoms, and estimates of the toxicity of each regimen. A panel of oncologists with expertise in radiation oncology, medical oncology and epidemiology discussed the above trial results and a literature review. The panel concluded that radiation was indicated in the palliation of hemoptysis, chest pain, dysphagia, and dyspnea, and that the results of the MRC studies provided reasonable estimations of the efficacy and toxicity of radiation in this setting. These studies show that symptoms are more often than not improved with palliative radiotherapy (symptom improvement rates ranged from about 50 to 85%) and that palliation lasted for a substantial portion of the patients' remaining survival. The panel could not reach uniform consensus on the appropriate fractionation for radiation given with palliative intent. The panel agreed that favourable patients with stage IIIB NSCLC should be offered combined modality therapy with the intent of prolonging survival, and that patient preferences regarding the risks and benefits of this therapy should be considered. Further study was recommended, namely, a randomized trial evaluating five fractions of radiation vs a single fraction, using patient-based evaluation of palliation. The panel also recommended phase II development of a combined chemotherapy and low-dose radiation protocol appropriate for future study.

Massive osteolysis of the chest in children: an unusual cause of respiratory distress.

Massive osteolysis, also called Gorham's disease, is an uncommon disease in which bone virtually disintegrates and is replaced by vascular fibrous connective tissue. The authors treated two children with massive osteolysis of the chest. Both conditions responded well to radiation therapy; one even showed evidence of reossification. Massive osteolysis should be considered in children who have spontaneous hemothorax. The bony structures should be examined for evidence of lytic lesions.

[Computed tomography in pre-irradiation topometry applied to diseases of the thoracic organs]. / Komp'iuternaia tomografiia v predluchevoi topometrii pri zabolavaniiakh organov grudnoi kletki.

The authors describe methods of pre-irradiation topometry in patients with thoracic tumors. They are based on patients' examination using an X-ray simulator and a computerized tomograph. The superiority of these methods over the previously used conventional methods was shown. The authors presented 77 cases observed by them. Radiation therapy plans in 48% of the patients were changed as a result of pre-irradiation investigation.