Browsing by Author "Gomez-Caamano, Antonio"

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    Evaluation of indirect damage and damage saturation effects in dose- response curves of hypofractionated radiotherapy of early-stage NSCLC and brain metastases
    (2021) Gago-Arias, Araceli; Neira, Sara; Pombar, Miguel; Gomez-Caamano, Antonio; Pardo-Montero, Juan
    Background and purpose: To investigate the possible contribution of indirect damage and damage saturation to tumour control obtained with SBRT/SRS treatments for early-stage NSCLC and brain metastases. Methods and materials: We have constructed a dataset of early-stage NSCLC and brain metastases dose- response. These data were fitted to models based on the linear-quadratic (LQ), the linear-quadratic-linear (LQL), and phenomenological modifications of the LQ-model to account for indirect cell damage. We use the Akaike-Information-Criterion formalism to compare performance, and studied the stability of the results with changes in fitting parameters and perturbations on dose/TCP values. Results: In NSCLC, a modified LQ-model with a beta-term increasing with dose yields the best-fits for oc/ fi = 10 Gy. Only the inclusion of very fast accelerated proliferation or low oc/fi values can eliminate such superiority. In brain, the LQL model yields the best-fits, and the ranking is not affected by variations of fitting parameters or dose/TCP perturbations. Conclusions: For oc/fi = 10 Gy, a modified LQ-model with a beta-term increasing with dose provides better fits to NSCLC dose-response curves. For brain metastases, the LQL provides the best fit. This might be interpreted as a hint of indirect damage in NSCLC, and damage saturation in brain metastases. The results for NSCLC are strongly dependent on the value of oc/fi and may require further investigation, while those for brain seem to be clearly significant. Our results can assist in the design of improved radiotherapy for NSCLC and brain metastases, aiming at avoiding over/under-treatment. (c) 2021 The Author(s). Published by Elsevier B.V. Radiotherapy and Oncology 101 (2021) 1-8 This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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    Radiobiological Meta-Analysis of the Response of Prostate Cancer to Different Fractionations: Evaluation of the Linear-Quadratic Response at Large Doses and the Effect of Risk and ADT
    (2023) Pardo-Montero, Juan; Gonzalez-Crespo, Isabel; Gomez-Caamano, Antonio; Gago-Arias, Araceli
    Prostate cancer is currently treated with different radiotherapy fractionations, including extreme hypofractionation. Some studies suggest that the response to large radiation doses per fraction may depart from the response predicted by the widely used linear-quadratic (LQ) model. In this study, we analysed a large dataset of dose-response data to evaluate departures from the LQ behaviour at large doses. In general, the response of prostate cancer to large doses of radiotherapy is best described by the LQ model, even though we observed some discrepancies at large doses for intermediate-risk patients, which merit further investigation. In addition, we characterised the radiobiological response of prostate cancer according to risk (low, intermediate, or high) and the addition or not of ADT to treatment.