Comparison of 3D-conformal and intensity-modulated radiation therapy for left-sided breast cancer

Abstract

Background: We compared 3D-conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT) planning for left-sided post-mastectomy patients. Aim: To compare the dose coverage of the planning target volume (PTV) and dose delivered to organs at risk (OAR) of 3D-CRT and IMRT plans. Setting: Department of Oncology, central South Africa. Methods: Twenty-six archived CT scans of patients with left-sided breast cancer were included. The 3D-CRT and IMRT plans were designed for each patient and compared using the Monaco© planning system (version 5.11.02). Statistical analysis was performed for PTV coverage (V95%, V98%, V105%) and radiation doses to the heart, ipsilateral lung, combined lungs, contralateral breast, and oesophagus. Results: The V98% and V105% target volume dose coverage for the 3D-CRT plans were 67.07% and 0.21%, respectively, compared to 92.32% and 1.10% of the IMRT plans. However, the IMRT plans’ mean volume of PTV, receiving 95% of the prescribed dose (PD), was 7.68% compared to the 3D-CRT’s 32.93%. The IMRT plans resulted in a V22 Gy 10% for the heart, with a value of 4.15%. The V18.87 Gy 45% values for the ipsilateral and combined lungs were 28.09% and 13.70%, respectively. The 3D-CRT plans showed a lower dose to the oesophagus (5.07 Gy) and contralateral breast (V5 Gy 15% = 3.51%). Conclusion: It was shown that 3D-CRT and IMRT treatment planning can effectively achieve clinical goals for post-mastectomy left-sided breast cancer radiotherapy. Contribution: The findings underscore the continuing relevance of 3D-CRT planning in oncology for optimal PTV dose coverage and low OAR dose.

Keywords

• breast cancer
• dosimetry
• three-dimensional conformal radiation therapy
• intensity-modulated radiation therapy
• organs at risk