Though the abscopal effect is extremely rare, it has been described in several cancers including melanoma, lymphoma, and kidney cancer.
Unexpectedly, other areas where the melanoma had spread (the spleen and the lymph nodes) but that were not directly targeted by the radiation therapy also benefited, consistent with the abscopal effect.
Scientists are not certain how the abscopal effect works to eliminate cancer in patients.
CancerWeb has defined an abscopal effect as "a reaction produced following irradiation but occurring outside the zone of actual radiation absorption.
The abscopal effect is admittedly rare and, in the past, was considered somewhat controversial, since it seemed to fly in the face of common sense.
What if it were possible to give cancer patients a substance that would actually make the abscopal effect a routine part of treatment?
Kanegesaki, have induced the abscopal effect in mice by first administering a biologically active protein or "chemokine" called ECI301.
It is not exactly a new finding that immune stimulants can trigger the abscopal effect.
The researchers' most important finding was that tumor growth at non-irradiated sites was inhibited, which indicated that ECI301 may have enhanced the abscopal effect.
There has already been at least one attempt to harness the abscopal effect in human patients.
Meanwhile, researchers in the US are actively investigating other mechanisms whereby the abscopal effect could potentially be used to enhance cancer treatment.
A study carried out by researchers from the Radiation Oncology branch of the National Cancer Institute and published in the journal Cancer Research has suggested that the abscopal effect might, in fact, be mediated through p53 (Camphausen 2003).