Radiation-immunotherapy combo can beat tumours

Radiotherapy, when combined with immunotherapy, displays potential avenues for future cancer treatment, according to a recent study.

The study has shown that the addition of an immune system-strengthening compound can extend the radiation therapy-induced immune response against the tumour sites and that this response even has an effect on tumours outside the radiation field.

As per Nicolle Rekers from Maastricht University Medical Centre, a combination of radiation therapy and L19-IL2, an immunotherapy agent, can increase significantly the immune response when given to mice with primary colorectal tumours. L19-IL2 is a combination of an antibody that targets the tumour blood vessels and a cytokine, a small protein important in cell signalling in the immune system.

The researchers found not only that the mice were tumour-free following treatment, but also that when re-injected with cancer cells 150 days after cure, they did not form new tumours. There was also an increase in the number of cells with an immunological memory.

Rekers said that radiation therapy damages the tumour creating a sort of tumour-specific vaccine. It feeds the immune system and ensures that it notices that something is wrong. What is unique about the latest experiments is that researchers have been able to create a so-called abscopal effect, where a localised radiation treatment has also had an effect on other tumour sites outside this radiation field.

"We believe that the risk/benefit equation is likely to come down firmly on the side of benefit. We hope that this treatment will not only destroy tumours, but also enable the immune system to develop a memory that allows it to annihilate them in the future as well," Ms Rekers will conclude.

The study has been presented to the ESTRO 35 conference.