Aim of the study: Remote high dose rate brachytherapy is an effective local treatment modality for central lung tumors and has the potential to improve survival time. Optimal dose and fractionation schemes have not been identified yet. We conducted a prospective randomized study to compare two treatment schedules in terms of survival time, local tumor control, and possible complications.
Design: Group 1 received 4 brachytherapies with a dose of 3.8 Gy (at a 10-mm depth) on a weekly basis, and group 2 received 2 treatments with 7.2 Gy (at a 10-mm depth) at a 3-week interval. At a depth of 5 mm, the calculated doses would be 8 and 15 Gy. This study is still ongoing. Here we report interim results.
Patients: Ninety-three patients with advanced cancer were included in the study; 44 were in group 1 and 49, in group 2. Both groups were comparable regarding age, sex, tumor stage, Karnofsky performance status, and histologic findings.
Interventions: A mean total irradiation dose of 13.4 +/- 5.2 Gy for group 1 and 13.7 +/- 4.4 for group 2 were applied (calculated at 10 mm from the source axis, equivalent to 27.9 Gy in group 1 and 28.5 Gy in group 2 at a 5-mm depth).
Results: The 1-year survival rate was 11.4% in group 1 and 20.4% in group 2. No significant difference in survival time was found, but mean survival was longer in group 2 (49 weeks) than in group 1 (26 weeks). Local control after 3 months was comparable in both groups. Fatal hemoptysis occurred at a similar rate in group 1 (22.2%) and in group 2 (21.1%).
Conclusion: High-dose rate brachytherapy with 2 x 7.2 Gy with a 3-week interval is equivalent to a 4 x 3.8-Gy regimen on a weekly basis. The shorter treatment schedule is more convenient for patients, does not cause more side effects, and provides an equal local tumor control.