Photodynamic therapy repeated without reinjection of Photofrin (porfimer sodium)

摘要

Background and objective: To compare the effectiveness in decreasing the amount of obstruction caused by endobronchial tumors when they are retreated with photodynamic therapy (PDT) several weeks after injection of Photofrin$+R$/ (porfimer sodium). Study design, materials and methods: The percentage of endobronchial obstruction from tumors before PDT and at the end of toilet bronchoscopy of 91 sites with PDT performed within 4 days after injection of porfimer sodium was compared to that obtained when PDT was repeated without re-injection of porfimer sodium in the time frames 2 - 4 weeks after injection to 11 sites and the period 4 - 8 weeks after injection to 17 sites. All patients were injected intravenously with 60 mg of Photofrin$+R$/ per square meter of body surface and all treatments were done with a power density of 500 mW/CF and a light dose of 400 J/CF delivered from cylinder diffusing fibers. Results: Paired Student's t tests and Wilcoxon signed ranks tests showed significant decreases in the percentage of endobronchial obstruction regardless of whether the PDT was first performed or repeated. Unpaired Student's t tests and Mann-Whitney U statistical comparisons showed a significant difference between the decrease of obstruction when treatment was performed within the first 4 days after injection (mean 41%) as compared to the repeated group 2 to 4 weeks after injection (mean 16%) and the group treated 4 to 8 weeks after injection (mean 19%). However there was no significant difference in the amount of decrease of obstruction between the 2 - 4 week group and the 4 - 8 week group. Conclusions: Photodynamic therapy to relieve endobronchial obstruction can be repeated without reinjection of Photofrin$+R$/ up to 8 weeks after injection with a significant decrease in the amount of obstruction. However, it will only be about 1/3 as effective as the initial treatment performed within the first four days of injection.