The impact of abdominal compression on outcome in patients treated with stereotactic body radiotherapy for primary lung cancer.

The aim of this study was to evaluate the impact of abdominal compression (AC) on outcome in patients treated with stereotactic body radiotherapy (SBRT) for primary lung cancer. We retrospectively reviewed data for 47 patients with histologically proven non-small cell lung cancer and lung tumour motion ≥ 8 mm treated with SBRT. Setup error was corrected based on bony structure. The differences in overall survival (OS), local control (LC) and disease-free survival (DFS) were evaluated to compare patients treated with AC (n = 22) and without AC (n = 25). The median follow-up was 42.6 months (range, 1.4-94.6 months). The differences in the 3-year OS, LC and DFS rate between the two groups were not statistically significant (P = 0.909, 0.209 and 0.639, respectively). However, the largest difference was observed in the LC rate, which was 82.5% (95% CI, 54.9-94.0%) for patients treated without AC and 65.4% (95% CI, 40.2-82.0%) for those treated with AC. After stratifying the patients into prognostic groups based on sex and T-stage, the LC difference increased in the group with an unfavourable prognosis. The present study suggests that AC might be associated with a worse LC rate after SBRT using a bony-structure-based set-up.