HIGH-DOSE-RATE AFTERLOADING INTRALUMINAL BRACHYTHERAPY IN MALIGNANT AIRWAY-OBSTRUCTION OF LUNG-CANCER

Purpose: This is a retrospective study to review the palliation rate, survival rate and complications of high dose rate (HDR) intraluminal brachytherapy in the treatment of malignant airway obstruction of lung cancer. Methods and Materials: A total of 225 high dose rate (HDR) brachytherapy treatments were delivered to 76 patients with symptomatic malignant airway obstruction by remote afterloading technique. An average of 7 Gy at a radius of 1 cm from the center of the source was delivered by Iridium-192 (Ir-192) sources. The majority of the patients received 3 fractions at 2 week intervals. Fifty-four patients received HDR brachytherapy as part of their initial treatment; 20 patients presented as symptomatic endobronchial recurrence. Two patients received YAG laser photoresection to open up the obstruction to allow insertion of the brachytherapy catheter. Fifty-nine patients received concurrent external beam irradiation. Forty-two patients were given 60-70 Gy in 6-7 weeks with curative intent. Seventeen patients were given 20-59 Gy in 2-5 weeks as a palliative measure. Nine patients received a radiosensitizer. One patient received concurrent chemotherapy. Results: The symptomatic response rates are as follows: dyspnea had an 87% response rate (59% partial response, 28% complete response), cough had a 79% response rate (47% partial response, 32% complete response), hemoptysis had a 95% response rate (38% partial response, 57% complete response), and postobstructive pneumonia had an 88% response rate (53% partial response, 35% complete response). Sixty-six patients had follow up endoscopic examination (1-3 months after brachytherapy). Their total response rate was 87% (52% partial response and 35% complete response). There were four acute complications: three cases of massive hemoptysis and one of mild hemoptysis. There are five late complications: three cases of radiation pneumonitis and two of esophagitis. At the time of this study, 55 patients have died with the maximum survival duration 113 months (9.4 years) from diagnosis date and 18 months from first HDR treatment. Twenty-one patients are still alive with a mean follow-up duration of 20 months from diagnosis date and 7.8 months from the first HDR treatment. Conclusion: HDR brachytherapy is an excellent modality for palliating symptomatic malignant airway obstruction with an acceptable complication rate; however, no definitive increase of survival rate was observed. Prospective clinical trials are needed to better define its merit regarding survival. This paper also includes a literature review and discussion of HDR brachytherapy on bronchogenic cancer.