Deductive reasoning.

While we still lack a plethora of prospective data measuring the synergy of radiation with immune checkpoint inhibition (ICI), here’s another lengthy review on all the theoretical reasons the combination approach, particularly for oligometastatic disease,  just makes sense. These include basic science examinations indicating distinct biologies among olimets as well as increased immunogenicity among irradiated tumor sites. The review gives a great discussion of the potential complementary effects of radiation and ICI. While the true extent of the “abscopal effect” is still debated, there is good evidence that immunotherapy response is greater with lower burden of disease. In the oligometastatic setting, this means the use of radiation to help eradicate larger burdens of disease could improve overall response to ICI. On the flip side, ICI might also enhance the efficacy of radiation. TBL: Use this review to brush up on the rationale for combining ICI and radiation for oligometastatic cancer. | Pitroda, Lancet Oncol 2019