Thoracic volume radiation sparing following endobronchial brachytherapy: a quantitative analysis

Area of Science:

• Oncology
• Radiation Oncology
• Pulmonology

Background:

• Malignant airway occlusion in Stage III non-small cell lung carcinoma (NSCLC) presents a therapeutic challenge.
• Patients with poor performance status are often ineligible for clinical trials.
• Endobronchial brachytherapy (EBT) offers a localized treatment option.

Purpose of the Study:

• To evaluate the efficacy of EBT as a boost prior to radical radiotherapy in patients with inoperable Stage III NSCLC and malignant airway occlusion.
• To assess the impact of EBT on airway reaeration and subsequent radiation therapy planning.
• To explore the correlation between reaeration and patient survival.

Main Methods:

• Retrospective analysis of 102 patients with Stage IIIA/IIIB NSCLC treated with EBT between 1986 and 1991.
• EBT delivered as low dose rate (20 Gy) or high dose rate (16 Gy).
• External beam radiotherapy (60 Gy) administered after a 10-14 day interval post-EBT.
• Sequential volume integration used to quantify thoracic volume sparing due to reaeration.

Main Results:

• Of 15 patients with atelectasis, 40% achieved complete reaeration and 27% partial reaeration.
• Complete reaeration led to a 47% reduction in ipsilateral thoracic radiation volume.
• Partial reaeration resulted in a 25% reduction in radiation volume.
• Reaerators showed a trend towards improved survival (36 weeks) compared to non-reaerators (24 weeks).

Conclusions:

• EBT is a viable treatment for malignant airway occlusion in Stage III NSCLC, particularly in patients with poor performance status.
• Reaeration following EBT can significantly reduce the volume of radiation therapy needed.
• EBT-induced reaeration may positively impact survival outcomes in NSCLC patients.