Linear No-threshold (LNT) vs. Hormesis: Paradigms, Assumptions, and Mathematical Conventions that Bias the Conclusions in Favor of LNT and Against hormesis

Low-dose radiotherapy effects the progression of anti-tumor response

The history of low-dose radiotherapy (LDRT or LDR) as a treatment modality for malignant tumors dates back to the 1920s. Even with the minimal total dose administered during treatment, LDRT can result in long-lasting remission. Autocrine and paracrine signaling are widely recognized for fostering the growth and development of tumor cells. LDRT exerts systemic anti-tumor effects through various mechanisms, such as enhancing the activity of immune cells and cytokines, shifting the immune response towards an anti-tumor phenotype, influencing gene expression, and blocking crucial immunosuppressive pathways. Additionally, LDRT has been demonstrated to enhance the infiltration of activated T cells and initiate a series of inflammatory processes while modulating the tumor microenvironment. In this context, the objective of receiving radiation is not to directly kill tumor cells but to reprogram the immune system. Enhancing anti-tumor immunity may be a critical mechanism by which LDRT plays a role in cancer suppression. Therefore, this review primarily focuses on the clinical and preclinical efficacy of LDRT in combination with other anti-cancer strategies, such as the interaction between LDRT and the tumor microenvironment, and the remodeling of the immune system.

Low Dose and Non-Targeted Radiation Effects in Environmental Protection and Medicine-A New Model Focusing on Electromagnetic Signaling

The role of signalling in initiating and perpetuating effects triggered by deposition of ionising radiation energy in parts of a system is very clear. Less clear are the very early steps involved in converting energy to chemical and biological effects in non-targeted parts of the system. The paper aims to present a new model, which could aid our understanding of the role of low dose effects in determining ultimate disease outcomes. We propose a key role for electromagnetic signals resulting from physico-chemical processes such as excitation decay, and acoustic waves. These lead to the initiation of damage response pathways such as elevation of reactive oxygen species and membrane associated changes in key ion channels. Critically, these signalling pathways allow coordination of responses across system levels. For example, depending on how these perturbations are transduced, adverse or beneficial outcomes may predominate. We suggest that by appreciating the importance of signalling and communication between multiple levels of organisation, a unified theory could emerge. This would allow the development of models incorporating time, space and system level to position data in appropriate areas of a multidimensional domain. We propose the use of the term "infosome" to capture the nature of radiation-induced communication systems which include physical as well as chemical signals. We have named our model "the variable response model" or "VRM" which allows for multiple outcomes following exposure to low doses or to signals from low dose irradiated cells, tissues or organisms. We suggest that the use of both dose and infosome in radiation protection might open up new conceptual avenues that could allow intrinsic uncertainty to be embraced within a holistic protection framework.

Le cancer radio-induit, le kangourou, et le petit lapin. Ou « la déclinaison radiobiologique du mythe de la Licorne Rose »

La relation linéaire sans seuil (RLSS), devenue un véritable dogme, conduit à affirmer l’existence de la nocivité des faibles doses de rayonnements ionisants faute de pouvoir démontrer leur innocuité. Il semble important de comprendre comment on en est arrivé à rendre dogmatique une non-théorie scientifique. Nous nous proposons dans cet article, après avoir montré combien la RLSS relève du mythe et non d’une approche scientifique, d’en exposer les origines et la genèse, indispensables à la compréhension de son actuel caractère de soi-disant vérité incontestable, puis d’illustrer les conséquences pratiques et épistémologiques préoccupantes que cette référence à la RLSS entraîne. Nous nous appuyons pour cela sur l’analyse critique de quelques-unes des études épidémiologiques qui prétendent la démontrer ou la confirmer.