Dosimetric Comparison of Five Radiotherapy Techniques in Left-Sided Breast Cancer Patients Following Breast-Conserving Surgery.

OBJECTIVE

This study aims to compare and evaluate the dosimetric characteristics of five radiotherapy techniques in left-sided breast cancer patients following breast-conserving surgery. The five radiotherapy techniques include three-dimensional conformal radiation therapy (3D-CRT), fixed-field intensity-modulated radiation therapy (ff-IMRT), volumetric modulated arc therapy (VMAT), hybrid 3D-CRT with IMRT (CRT + IMRT), and hybrid 3D-CRT with VMAT (CRT + VMAT).

PATIENTS AND

METHODS

Ten patients with left-sided breast cancer who received postlumpectomy radiotherapy at the Department of Radiation Oncology, First Hospital of Qinhuangdao, between June 1, 2020, and June 1, 2021, were randomly enrolled in this study. For each patient, five distinct treatment plans were designed using the five aforementioned techniques (3D-CRT, ff-IMRT, VMAT, CRT + IMRT, and CRT + VMAT) based on identical computed tomography (CT) imaging datasets. Dosimetric parameters for the tumor target volume, organs at risk (OARs), and normal tissues (defined as body minus planning target volume [PTV], termed B-P) were analyzed and compared using dose-volume histograms (DVHs) and isodose distributions.

RESULTS

The CRT + VMAT technique demonstrated superior PTV dose coverage, conformity, and homogeneity compared to 3D-CRT, ff-IMRT, VMAT, and CRT + IMRT (p < 0.05). In contrast, the VMAT technique achieved significantly lower V30 (%) values for bilateral lungs and ipsilateral lung than 3D-CRT, ff-IMRT, CRT + IMRT, and CRT + VMAT (p < 0.05). The CRT + IMRT technique reduced V5 (%) values for bilateral lungs, ipsilateral lung, and heart compared to 3D-CRT, ff-IMRT, VMAT, and CRT + VMAT (p < 0.05). Finally, 3D-CRT required the fewest monitor units (MUs) and shortest treatment time among all techniques (p < 0.05).

CONCLUSION

Clinicians may tailor radiotherapy plans to individual patients based on the distinct dosimetric profiles of each technique. For patients requiring optimal PTV dose distribution, the CRT + VMAT technique is suggest. For enhanced cardiopulmonary protection (e.g., reduced lung/heart doses), ff-IMRT or CRT + IMRT may be prioritized. Additionally, 3D-CRT should be the first choice for patients needing rapid fractionated treatment due to its efficiency in minimizing MUs and treatment time.