Radiobiological Evaluation and Comparison of Treatment Plans in Two Methods of 3D Adaptive Radiation Therapy and Tomotherapy for Left Pendular Breast Cancer and the Risk of Pericarditis and Pneumonia

This study aimed to compare the tumor control probability (TCP) and the normal tissue complications probability (NTCP) of three-dimensional adaptive radiation therapy (3D-CRT) and tomotherapy for left pendular breast cancer using radiobiological models.

The current study was conducted on 20 patients with left pendular breast cancer who underwent treatment planning using the treatment planning system for 3D-CRT and tomotherapy. A prescribed dose of 50 Gy was implemented for the planning target volume (PTV) in both 3D-CRT and tomotherapy designs. The Equivalent Uniform Dose (EUD) of the Niemierko model was used to estimate the tumor control probability (TCP) and the normal tissue complications probability (NTCP).

According to the results, the average TCP values for 3D-CRT and tomotherapy plans were 99.07 ± 0.13 and 99.32 ± 0.09, respectively, which did not show a statistically significant difference. The NTCP values for the lung and heart were significantly lower in tomotherapy plans compared to 3D-CRT plans.

From a radiobiological point of view, the results showed that 3D-CRT resulted in a lower NTCP for the ipsilateral lung. In contrast, for TCP calculations, tomotherapy plans showed higher values compared to 3D-CRT plans.