Abscopal effect

R.H. Mole proposed the term "abscopal" ('ab' - away from, 'scopus' - target) in 1953 to refer to effects of ionizing radiation "at a distance from the irradiated volume but within the same organism".

For instance, chemotherapeutics commonly circulate through the blood stream and therefore exclude the possibility of any abscopal response.

[11] Vice versa, the abscopal effect is abolished after experimental depletion of T cells in various animal models.

In contrast, the combination of immunomodulatory drugs such as ipilimumab and pembrolizumab can partially reconstitute systemic anti-tumor immune reactions induced after local tumor radiotherapy.

In this context, it was proposed that radiation doses above 10 to 12 Gray might be ineffective in inducing immunogenic forms of cell death.

Proposed mechanism of the abscopal effect, mediated by the immune system. Here, local radiation causes tumor cell death, which is followed by adaptive immune system recognition, not unlike a vaccine.