Treatment of roentogenographically occult endobronchial carcinoma with external beam radiotherapy and intraluminal low dose rate brachytherapy

Purpose: A prospective Phase II study was done to investigate the treatment results of combined external beam and intraluminal radiotherapy in roentogenographically occult inoperable endobronchial carcinoma. Methods and Materials: In 41 patients (all male) with roentogenographically occult endobronchial carcinoma, a combination of external beam radiotherapy using linac x-ray and intraluminal low dose rate brachytherapy via Ir-192 thin wire (1.48 GBq) was performed. External beam radiotherapy comprised of 40 Gy in 20 fractions over 4 weeks was carried out, whereas intraluminal brachytherapy consisted of 25 Gy in five fractions over 2.5-5 weeks. The dose reference point for brachytherapy varied (3-9 mm) according to a diameter of the bronchus. Results: Excluding two cases in which bronchoscopy was refused (1) and was still being treatment (1), 39 patients were treated according to plan. By the last intraluminal brachytherapy, no tumor was endoscopically identifiable in all cases; The follow-up period ranged from 1-41 months, with a median of 24.5 months. Recurrence occurred in two cases, with subsequent surgery: one is alive without cancer and the other died of uncontrolled lung cancer at 35 months. Radiation pneumonitis was observed in two cases for whom glucocorticoid and antibiotics were administered. Both recovered and resumed work. Other recurrences or severe complications from irradiation have not been observed so far. Two or more separate primary cancers were identified in 19 (lung, 10; other organs, 10) of the 41 patients. Conclusion: The combination treatment of external beam radiotherapy and intraluminal brachytherapy is effective for roentogenographically occult endobronchial carcinoma with acceptable complications.