Lung Cancer Related Central Airway Obstruction: Who Benefits Better from Radiotherapy?

Abstract

We aimed to assess the efficacy of external beam radiotherapy (EBRT) in central airway obstruction (CAO) and associated factors for metastatic lung cancer (MLC) patients. Records of 72 MLC patients presenting with CAO were retrospectively analyzed. The serial chests X-rays prior and after the EBRT were compared for response assessment. The primary end-point was radiologic response, while overall-(OS) and CAO-free survival, and predictors of better outcomes constituted secondary endpoints. The EBRT doses ranged between 8 to 40 Gy (1-13 fractions). Median follow-up and OS were 5.6 (range: 1.3-17.8) and 7.6 months (95% CI: 6.5-8.7), respectively. Objective CAO resolution was achieved in 58 patients (80.6%) on serial chest X-rays with a median time to maximum CAO response of 23 days (range: 3-86). In responders the response was durable (8.1 months) almost nearly for all their remaining life spans (8.3 months) with only 19.0% CAO recurrences. Median OS was also significantly longer in responders (8.3 vs. 2.4 months; p<0.001). Small-cell histology (p=0.002), tumor size <5.3 cm (p=0.007), and biologically equivalent dose (BED10) >= 39 Gy (p<0.001) were associated with better CAO response, while the presence of CAO response (p<0.001) and BED10 >= 39 Gy (p=0.008) were the factors to relate with better OS on multivariate analyses. The EBRT proves effective and durable CAO palliation with only 19.0% re-CAO rate in MLC patients. Better CAO responses may be achieved in patients treated with smaller tumor size, small-cell histology, and higher BED10 values.