Jessica L Conway1, Leigh Conroy2, Lindsay Harper3, Marie Scheifele3, Haocheng Li4, Wendy L Smith2, Tannis Graham3, Tien Phan5, Ivo A Olivotto5. 1. Division of Radiation Oncology, University of Calgary, Calgary, Alberta. Electronic address: Jessica.Conway@ahs.ca. 2. Division of Medical Physics, University of Calgary, Calgary, Alberta. 3. Division of Radiation Therapy, Tom Baker Cancer Centre, Calgary, Alberta. 4. Division of Biostatistics, University of Calgary, Calgary, Alberta. 5. Division of Radiation Oncology, University of Calgary, Calgary, Alberta.
Abstract
PURPOSE: The goal of the work described here was to determine whether deep inspiration breath-hold (DIBH) produces a clinically meaningful reduction in pulmonary dose compared with free breathing (FB) during locoregional radiation for right-sided breast cancer. METHODS AND MATERIALS: Four-field, modified-wide tangent plans with full nodal coverage were developed for 30 consecutive patients on paired DIBH and FB CT scans. Nodes were contoured according to European Society for Radiotherapy and Oncology guidelines. Plan metrics were compared using Wilcoxon signed-rank testing. RESULTS: In 21 patients (70%), there was a ≥5% reduction in ipsilateral lung V20Gy with DIBH compared with FB. The mean decrease in ipsilateral lung V20Gy was 7.8% (0%-20%, P < .001). The mean lung dose decreased on average by 3.4 Gy with DIBH (-0.2 to 9.1, P < .001). The mean reduction in liver volume receiving 50% of the prescribed dose was 42.3 cm3 (0-178.9 cm3, P < .001). CONCLUSIONS: DIBH reduced ipsilateral lung V20Gy by ≥5% in the majority of patients. For some patients, the volume of liver receiving a potentially toxic dose decreased with DIBH. DIBH should be available as a treatment strategy to reduce ipsilateral lung V20Gy prior to compromising internal mammary chain nodal coverage for patients with right-sided breast cancer during locoregional radiation therapy if the V20Gy on FB exceeds 30%.
PURPOSE: The goal of the work described here was to determine whether deep inspiration breath-hold (DIBH) produces a clinically meaningful reduction in pulmonary dose compared with free breathing (FB) during locoregional radiation for right-sided breast cancer. METHODS AND MATERIALS: Four-field, modified-wide tangent plans with full nodal coverage were developed for 30 consecutive patients on paired DIBH and FB CT scans. Nodes were contoured according to European Society for Radiotherapy and Oncology guidelines. Plan metrics were compared using Wilcoxon signed-rank testing. RESULTS: In 21 patients (70%), there was a ≥5% reduction in ipsilateral lung V20Gy with DIBH compared with FB. The mean decrease in ipsilateral lung V20Gy was 7.8% (0%-20%, P < .001). The mean lung dose decreased on average by 3.4 Gy with DIBH (-0.2 to 9.1, P < .001). The mean reduction in liver volume receiving 50% of the prescribed dose was 42.3 cm3 (0-178.9 cm3, P < .001). CONCLUSIONS:DIBH reduced ipsilateral lung V20Gy by ≥5% in the majority of patients. For some patients, the volume of liver receiving a potentially toxic dose decreased with DIBH. DIBH should be available as a treatment strategy to reduce ipsilateral lung V20Gy prior to compromising internal mammary chain nodal coverage for patients with right-sided breast cancer during locoregional radiation therapy if the V20Gy on FB exceeds 30%.