Dr. Charles G. Drake, of New York-Presbyterian/Columbia University Medical Center, discusses the thinking behind combining radiation therapy with immunotherapy.
Dr. Drake says: “The basic idea is that radiation, and perhaps other local modalities like cryotherapy, leads to destruction of tumor cells. If they’re destroyed in a way that’s immunogenic or pro-immunogenic, then the dying cells are taken up by resident antigen-presenting cells. These antigen-presenting cells get activated; they traffic to the draining lymph node, if you’re lucky. If they traffic to the draining lymph nodes, and then activate a systemic immune response (T cells), then maybe you can turn a local therapy into a systemic therapy. When that happens, it’s called the abscopal effect. We can demonstrate this in mice fairly readily, but it’s quite hard to demonstrate in humans.
In the literature, it’s not that common. There’s a review paper that reports around 60 total cases in the world that are clearly documented. But if you talk to people who take care of patients, everybody has one or two that they can talk about.”