Evaluation of indirect damage and damage saturation effects in dose–response curves of hypofractionated radiotherapy of early-stage NSCLC and brain metastases

Background and purposeTo investigate the possible contribution of indirect damage saturation to tumour control obtained with SBRT/SRS treatments for early-stage NSCLC brain metastases.Methods materialsWe have constructed a dataset metastases dose–response. These data were fitted models based on linear-quadratic (LQ), linear-quadratic-linear (LQL), phenomenological modifications LQ-model account cell damage. We use Akaike-Information-Criterion formalism compare performance, studied stability results changes in fitting parameters perturbations dose/TCP values.ResultsIn NSCLC, modified beta-term increasing dose yields best-fits α/β = 10 Gy. Only inclusion very fast accelerated proliferation or low values can eliminate such superiority. In brain, LQL model best-fits, ranking is not affected by variations perturbations.ConclusionsFor Gy, provides better fits dose–response curves. For metastases, best fit. This might be interpreted as hint metastases. The are strongly dependent value may require further investigation, while those seem clearly significant. Our assist design improved radiotherapy aiming at avoiding over/under-treatment.