Comparative Radiobiological Evaluation of Radiotherapy Techniques Using Equivalent Uniform Dose, Tumor Control Probability, and Normal Tissue Complication Probability in Postmastectomy Breast Cancer
Garima Gaur, Gurpreet Kaur, Baltej Singh, Pardeep Garg, Vinod Kumar Dangwal, Raja Paramjeet Singh BanipalAbstract
Introduction:
Postmastectomy radiotherapy plays a pivotal role in improving locoregional control and survival outcomes in early as well as in advanced-stage breast cancer patients. With the transition from conventional radiotherapy techniques to advanced intensity-modulated approaches, evaluation based solely on physical dose parameters is no longer sufficient. Radiobiological modelling provides a more clinically meaningful framework by quantifying tumor control and normal tissue complications.
Objectives:
The objective of this prospective study was to evaluate the radiobiological differences between three radiotherapy planning techniques, namely three-dimensional conformal radiotherapy (3DCRT), field-in-field forward planned intensity modulated radiotherapy (FIF-FP-IMRT), and inversely planned intensity modulated radiotherapy (IP-IMRT) in postmastectomy breast cancer patients.
Materials and Methods:
The present prospective study involved 150 postmastectomy breast cancer patients who have undergone chemotherapy treatment. Each patient was planned with three radiotherapy planning techniques, namely 3DCRT, FIF-FP-IMRT, and IP-IMRT for comparative radiobiological analysis. Radiobiological parameters, namely tumor control probability (TCP) and normal tissue complication probability (NTCP), were then calculated and compared for the three planning techniques.
Results:
The mean TCP values were comparable among all three techniques, with no statistically significant difference. However, significant differences were observed in most of the NTCP parameters (
Conclusion:
The present study demonstrates that advanced radiotherapy planning techniques provide significant radiobiological advantages over conventional techniques in postmastectomy breast cancer patients. Among the three evaluated techniques, IP-IMRT showed the most favorable radiobiological profile, followed by FIF-FP-IMRT, while 3DCRT showed comparatively higher NTCP.