Low dose rate versus high dose rate intraluminal brachytherapy for malignant endobronchial tumors.

Although the evolution from low dose rate to high dose rate brachytherapy for malignant endobronchial malignancies was primarily based on economy, patient convenience, and radiation protection, the difference in therapeutic index, if any, between these two modalities must be kept in mind. Our experience with both methods permits assessment of the feasibility of replacing low dose rate brachytherapy with high dose rate brachytherapy. Results with our first 110 patients (group 1) treated with low dose rate brachytherapy (133 procedures) were compared with results with our initial 59 consecutive patients (group 2) treated with high dose rate brachytherapy (161 procedures). In group 1, patients were treated with one or two sessions of 30-60 Gy each calculated at a 1 cm radius. In patients in group 2, we aimed at three weekly sessions of 7 Gy each calculated at a 1 cm radius. External beam irradiation therapy had previously been given to 88% of patients in group 1 and to 85% of patients in group 2. Laser bronchoscopy was performed in 36% of patients in group 1 and in 24% of patients in group 2 before brachytherapy. Clinical or bronchoscopic improvement was noted in 72% of patients in group 1 and in 85% of patients in group 2 (p > 0.05). Complication rates were low and comparable. Survival was similar in both groups (median < 6 months). Although both low dose rate and high dose rate brachytherapy appear equally effective in palliation for malignant endobronchial obstruction, we are now practicing the latter exclusively.

Intraluminal low-dose rate brachytherapy for malignant endobronchial obstruction.

From October 1985 through October 1989, 87 patients underwent 105 intraluminal brachytherapy treatments for endobronchial or endotracheal malignant tumors. Low-dose rate iridium-192 seeds were used. Of the 60 patients treated for primary lung carcinoma, 52 patients (87%) had previously received full-course external beam radiotherapy to the tumor sites. Ten patients were treated for symptomatic metastatic disease, and one patient had extension of tumor into the trachea from carcinoma of the cervical esophagus. Clinical or bronchoscopic improvement was noted in 42 patients (59%). No significant difference in the response rate was observed between various types of tumor. Patients who were treated with a radiation dose larger than 2500 cGy at a 2 cm radius had a significantly greater response rate (77%) than patients treated with a dose less than 2500 cGy (38%) (p = 0.001). A trend toward better results was apparent in patients who had undergone Nd:YAG laser bronchoscopy in the 2 weeks before brachytherapy. The treatments were well tolerated, and the incidence of serious complications was low and acceptable.

Pulmonary venous infarction.

Pulmonary venous infarction, although rare, can develop in patients with the various pathologic conditions outlined. The triad of cough, dyspnea, and hemoptysis should raise clinical suspicion. The venous phase of pulmonary arteriography is the best way to document pulmonary venous obstruction, although MR imaging may also prove useful in the future. Treatment of patients with pulmonary venous infarction should be determined on the basis of the obstructing pathologic findings. Antibiotic therapy is important, as evidenced by the early experimental experience with this condition. It may be the only treatment available to patients with idiopathic fibrosing mediastinitis. Pulmonary resection, however, can be accomplished when a localized obstructing lesion is identified.

Pulmonary venous infarction secondary to squamous cell carcinoma.

This type of pulmonary venous infarction has not been previously reported, namely: pulmonary vein obstruction from squamous cell carcinoma. Furthermore, this case is unique in that the characteristic pathologic vascular changes observed with pulmonary venous infarction were contrasted with a noninfarcted upper lobe that was removed from the same patient one year later.

When drug therapy for lung disease affects the heart.

The development of effective drugs for chronic lung disease, especially bronchodilator aerosols, has been a boon to patients and physicians alike, but these agents also may provoke arrhythmias. Fluorocarbon propellants, once regarded as harmless, are now known to disrupt cardiac function, sensitizing the heart to the arrhythmic effects of sympathomimetic amines. Catecholamine drugs as a group have a strong impact on heart rate and contractility. But the danger of rhythm disturbances often can be reduced by cutting the dosage or choosing a preparation with more beta 2 activity. Methylxanthines, generally safer than catecholamines, nevertheless must be used with caution and preferably alone in patients with heart and lung disease.