Beyond DVH: Integrating Tumor Control Probability and Normal Tissue Complication Probability Into Breast Radiotherapy Treatment Plan Evaluation.
Authors: Tania Afroz
Institution: Ahsania Mission Cancer and General Hospital
Introduction
Dose–volume histogram (DVH) analysis is fundamental to radiotherapy treatment plan evaluation. However, conventional dosimetric parameters do not directly estimate tumor control probability (TCP) or normal tissue complication probability (NTCP). Integrating radiobiological modeling with DVH analysis may provide additional information for evaluating target coverage and normal-tissue dose distributions in left-sided chest-wall radiotherapy. To investigate the relationship between conventional DVH parameters and model-estimated TCP and NTCP in patients receiving three-dimensional conformal radiotherapy (3D-CRT) for left-sided chest-wall irradiation.
Methods
This retrospective dosimetric and radiobiological modeling study will include 15-20 eligible patients treated with 3D-CRT for left-sided chest-wall irradiation. Anonymised treatment-planning data and dose–volume histograms will be obtained from the Monaco treatment planning system. Target coverage and dose distributions to selected organs at risk, particularly the heart and ipsilateral lung, will be evaluated using conventional DVH parameters. TCP will be estimated using a published radiobiological tumour-control model, while NTCP will be calculated using the Lyman–Kutcher–Burman model with appropriate, endpoint-specific published parameters. Statistical analyses will assess the relationships between conventional dosimetric parameters and model-derived probabilities. Sensitivity analysis will examine the influence of radiobiological parameter selection on the estimated outcomes.
Results
The study will characterize the relationships between conventional DVH parameters and radiobiological estimates and assess whether TCP/NTCP modeling helps distinguish treatment plans with comparable target coverage but different organ-at-risk dose distributions.
Conclusion
Integrating TCP and NTCP modeling with conventional DVH analysis may provide a complementary approach to evaluating left-sided chest-wall radiotherapy plans. The clinical interpretation of these estimates will depend on model validity, parameter selection and uncertainty, and the findings will not be interpreted as observed clinical outcomes in the absence of clinical follow-up data.
