| ObjectiveThe incidence of breast cancer is the highest in female patients. Whole-breast radiotherapy after breast conserving surgery has been the standard treatment for early-stage breast cancer. With progress of radiation technologies, intensity modulated radiation therapy (IMRT) is used more and more widely in the whole breast external irradiation. But its accuracy is limited to the breath motion. Cardiac disease and pulmonary complications are documented risk factors in tangential breast irradiation. Active Breathing Control (ABC) system restricted the breath in patients during radiotherapy. We explored whether the moderate deep inspiration breath hold (mDIBH) techusing Active Breathing Control (ABC) system during left-sided breast irradiation provides a particular possibility to substantially reduce cardiopulmonary doses.Expect to give a reference for the clinical application.MethodsA total of 22 patients with left-sided breast cancer underwent three computed tomography scans using moderate deep inspiration breath hold (mDIBH) and free breathing (FB) and moderate deep expiratory breath hold (mDEBH) techniques after breast-conserving surgery. The scans were retrospectively replanned using standardized criteria for the purpose of this study. Three separate treatment plans were generated for each patient, with and without ABC-mDIBH to comparatively evaluate dose-volume parameters of both plans. Doses to the heart, ipsilateral lung were assessed. The effect of ABC on mean lung dose (MLD), V20 (percentage volumes receiving doses≥ 20 Gy), V30 (percentage volumes receiving doses> 30 Gy) and mean heart dose(MHD), V20, V30 was calculated.ResultsThe CI and HI in three type plans were no significant difference (0.70 ± 0.64; 0.69 ± 0.64; 0.67 ± 0.70,,P=0.43; 19 ± 2.4; 18 ± 3.0; 18 ± 3.6, P=0.54). There were no significant difference among CTV and PTV under different breath conditions. The CTV of the plans in FB, mDIBH, mDEBH were (708.91±158.93) cm3, (699.76±157.46) cm3, (711.52±158.76) cm3, respectively, P>0.05. The PTV of the plans in FB, mDIBH, mDEBH were (911.99±170.56) cm3, (909.87±174.55) cm3, (920.02±173.36) cm3, respectively, P>0.05. The use of ABC-mDIBH resulted in statistically significant improvement in physical lung parameters of V20, V30 and mean lung dose (MLD) (p<0.001). The V20 and V30 of ipsilateral lung in mDIBH were lower than those in FB and mDEBH. The V20 were (12.57±1.33)%vs. (14.86 ±2.11)%vs. (16.35 ±2.29)%, respectively, P=0.000. The V30 were (11.09±1.41)%vs. (13.54±2.17)%vs. (15.06±2.21)% respectively, P=0.000. Significant differences were found between the FB and mDIBH and mDEBH plans for mean heart dose (535.96±99.76cGy vs. 257.96±59.32cGy vs.666.58±134.21cGy), heart V30 (6.04±1.54% vs.1.65±0.72% vs. 8.57±2.55%), V20 (7.52±1.82% vs.2.37±0.86%vs.10.14±2.64%) (P<0.001).ConclusionThis respiratory management strategy is a promising tool that may be routinely used for the treatment of patients with early-stage left-sided breast cancer. The use of a mDIBH technique using ABC system in breathing adapted radiotherapy is easily feasible in daily practice and significantly reduces the radiation doses to the heart and lung, therefore have potential for decreasing treatment-related morbidity and mortality. |
PDF Full Text Request