LOW-DOSE RATE VERSUS HIGH-DOSE-RATE INTRALUMINAL BRACHYTHERAPY FOR MALIGNANT ENDOBRONCHIAL TUMORS

Although the evolution from low dose rate to high dose rate brachyther apy for malignant endobronchial malignancies was primarily based on ec onomy, patient convenience, and radiation protection, the difference i n therapeutic index, if any, between these two modalities must be kept in mind. Our experience with both methods permits assessment of the f easibility of replacing low dose rate brachytherapy with high dose rat e 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 wit h 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 session s 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% o f patients in group 1 and in 24% of patients in group 2 before brachyt herapy. Clinical or bronchoscopic improvement was noted in 72% of pati ents in group 1 and in 85% of patients in group 2 (p > 0.05). Complica tion rates were low and comparable. Survival was similar in both group s (median < 6 months). Although both low dose rate and high dose rate brachytherapy appear equally effective in palliation for malignant end obronchial obstruction, we are now practicing the latter exclusively.