A practical non-custom abdominal corset-based approach for diaphragm motion management in stereotactic body radiotherapy

In Stereotactic body radiation therapy (SBRT), abdominal compression devices are commonly used to manage respiratory motion. The high cost, bulky design, and low patient tolerance of these devices limit utilization. This study aimed to evaluate the impact of non-custom lumbosacral corsets on respiratory motion and clinical outcomes in SBRT delivered for a heterogeneous cohort of lower thoracic and upper abdominal lesions. A total of 46 patients underwent two separate slow-CT scans with 1 mm slice thickness, with and without the corset. A “traditional lumbosacral corset with an extensile bands” was used. The diaphragm motion was evaluated with diaphragm amplitude, Δamplitude, liver and spleen artifact volumes, and their changes (Δvolume). All patients were treated with the corset during all SBRT fractions. Clinical outcomes were assessed in patients with a minimum follow-up of 3 months. Statistical analyses were performed using Wilcoxon signed-rank and paired t-tests, Spearman’s correlation, and both univariate and multivariate linear regression. Paired comparisons and regression analyses were performed to assess motion reduction and its association with patient factors. The median age was 67 years (45–82), with 17 female and 29 male patients. The corset decreased the diaphragm amplitude from 1.13 cm (0.20–3.01) to 0.55 cm (0.17–1.93) (p < 0.001). Initial diaphragm amplitude ≥ 1 cm decreased − 0.84 cm; <0.5 cm decreased − 0.13 cm (p < 0.001). Following corset application, the proportion of patients with diaphragm amplitude ≤ 1 cm increased from 39.1% (n = 18) to 82.6% (n = 38), approximately doubling, while those with amplitude ≤ 0.5 cm increased from 13.0% (n = 6) to 47.8% (n = 22), representing nearly a fourfold increase. Both univariate and multivariate analyses found no significant effect of gender, age, or body mass index on Δamplitude and Δvolume values with the corset (p > 0.05). At 6 months, 73.9% of patients showed complete response. Local progression occurred in 5 (%10.9) patients. One- and two-year local control rates were 89.0% and 65.0%. Non-custom lumbosacral corsets effectively reduced diaphragm motion, particularly in patients with baseline amplitudes > 1 cm. This low-cost, and well-tolerated approach offers a reliable alternative for motion management during SBRT in radiotherapy centers lacking dedicated motion management equipment.