Endobronchial brachytherapy using low dose rate iridium-192 thin wire. Three-institutional retrospective analysis.

A total of 133 cases with 149 lesions consisting mainly of lung cancers with endobronchial lesions that were treated with low dose rate intraluminal brachytherapy from three institute were analyzed. All but one case had lung cancer. The roles of this radiotherapy were various. Of the cases, 91 with 101 lesions were roentgenographically occult endobronchial carcinoma (ROEC), 19 with 25 lesions were postoperative endobronchial recurrence of lung cancer (PER), thirteen cases were lung cancer without ROEC (advanced cancer).<BR>Brachytherapy alone was performed on a few lesions, in the other cases, a combination external beam radiotherapy using 4 to 10 MV linac x-ray and intraluminal low dose rate brachytherapy via 192 Iridium thin wire was performed. Most lesions were given 1.8 to 2.2 Gy per fraction with external beam radiotherapy and 4 to 6 Gy per fraction with brachytherapy, but their total doses differed widely. The 5 year overall survival, cause apecific survival, disease free rate of ROEC were respectively 52.1 %, 85.8 %, 82.2 %, the 5 year overall survival and cause specific survival of PER were 29.3 %, 39.4 %, and the 3 year overall survival and cause specific survival of advanced lung cancer were 20.1 %, 38.4 %. Radiation dose did not have a significant influence on either survival or recurrence. Of ROEC cases, the recurrence rate of patients who had over 20 mm lesions was significantly high. As for radiation injury, radiation pneumonitis, bronchial stenosis, ulcer formation and bleeding were observed, and 2 patients died due to radiation pneumonitis and bleeding. We observed a significantly high rate of radiation injury in ROEC patients who were treated with under 25 Gy for brachythrapy, over 40 Gy for external beam radiotherapy and over 65 Gy for total dose.<BR>We thought this treatment was good for small lesions such as ROEC or PER. But, because these cases were treated widely different doses and the number of cases was small, we could not find the relationship between dose and recurrence of all groups, or the relationship between dose and radiation injury of PER and advanced cancer groups. We hope to be able to conduct a multiinstitute prospective study.