Document Type : Original Paper
Department of Radiation Oncology, Capitol Hospital, Jalandhar, Punjab
Introduction: The study was conducted to compare the dosimetric variabilities and efficacy of treatment delivery between intensity-modulated radiotherapy (IMRT) plans with RapidArc plans in left-sided carcinoma breast, centering on target coverage, doses received by organs at risk (OARs), average monitor units (MUs) per fraction, and treatment time.
Materials and Methods: Thirty patients with left-sided breast cancer planned for adjuvant radiation therapy were enrolled for this prospective, observational study. For each patient, two plans were generated using the IMRT and RapidArc techniques. Dose-volume histograms (DVHs) for the target volume and OARs were compared for these two techniques. The average MUs and the treatment time were used as markers to assess the efficacy of treatment delivery in these techniques.
Results: There was an insignificant difference in the planning target volume (PTV) homogeneity and conformity index between IMRT and RapidArc plans. We found IMRT plans to be superior to RapidArc plans in terms of OARs sparing (I/L lung, heart, C/L breast, C/L lung, and esophagus). The average MUs per fraction was significantly lower for RapidArc (535.05 ± 105.42) than for IMRT (913.57 ± 129.35) resulting in treatment delivery time being statistically shorter for RapidArc plans as compared to IMRT plans (p=0.001).
Conclusion: For left-sided breast cancer patients, RapidArc plans were capable of delivering an equivalent treatment plan to IMRT with regard to PTV coverage. IMRT plans provided better OARs sparing while RapidArc plans enabled higher efficacy in terms of lower MUs and shorter treatment delivery time. However, further studies are required to establish these dosimetric advantages being translated to improvements in the clinical outcomes of these patients.