Comparison of Different Models in Calculation of Tumor Control Probability and Normal Tissue Complication Probability...

The aim of this study is to compare tumor control probability (TCP) for the planning target volume (PTV) using Poisson, Niemierko, and Zaider-Minerbo models, and normal tissue complication probability (NTCP) for organs at risk (OARs) using Niemierko, Lyman-Kutcher-Burman (LKB) and relative seriality (RS) models.

Radiotherapy dosimetry data of sixty breast cancer patients were utilized to calculate TCP and NTCP with various models. Patients underwent planning using a 16-slice CT scanner, delivering 50 Gy in 25 fractions using 6 MV photon beam energy and the Monaco treatment planning system (TPS).

Significant differences in TCP were found between Poisson and Zaider-Minerbo models, and between Zaider-Minerbo and equivalent uniform dose (EUD) based models, with no difference between Poisson and EUD-based models. For NTCP, differences were observed between RS model and LKB for heart, spinal cord, and thyroid, as well as between RS model and EUD-based model for the heart, spinal cord and thyroid. LKB and EUD-based models showed differences when considering the lungs as an additional OAR.

Differences among models for calculation TCP and NTCP emphasize the importance of considering specific treatment objectives and patient characteristics in breast cancer radiotherapy planning, ensuring optimized therapeutic outcomes while minimizing adverse effects on healthy tissues.