Radiotherapy responses may be improved with targeted immunotherapy, study suggests

A new study suggests that targeted immunotherapy could make cancers that are resistant to radiotherapy more responsive to treatment.

The study, conducted by scientists at The Institute of Cancer Research, London in collaboration with the University of Leeds and The Francis Crick Institute, studied inflammation in bowel tumour samples taken before and after radiotherapy from 53 patients.

The researchers aimed to understand how tumour immune activity before and after radiotherapy treatment varies between patients who respond or do not respond well to treatment.

The study found that by profiling the immune landscape of cancers before therapy, researchers could identify which patients are likely to respond to radiotherapy, and also who might benefit from ‘priming’ their tumour with immunotherapy.

According to the study, published in the Journal for ImmunoTherapy of Cancer, the effectiveness of radiotherapy partly depends on the level of inflammation in tumours before and after treatment.

Patients in the study who had a poor response to immunotherapy began with chronically inflamed tumours – the tumour inflammation level showed only minimal changes following radiotherapy.

On the flip side, patients who responded well to radiotherapy started with a relatively low inflammation tumour landscape, which increased following treatment.

The findings, according to the researchers, show that the careful timing of a combination of immunotherapy and radiotherapy could become a new way of treating resistant cancers.

“Our study has shown that the immune landscape and levels of inflammation within cancers is crucial to determining how they respond to radiotherapy,” said Anguraj Sadanandam, study leader and leader of the Systems and Precision Cancer Medicine team at The Institute of Cancer Research, London.

It suggests that combining radiotherapy with immunotherapy could prove a highly potent mixture – improving our ability to eliminate hard-to-treat cancers further still

“Now we want to improve our understanding of how to combine and sequence radiotherapy and immunotherapy together to maximise the treatment response for the individual biology of each patient,” he added.

The study, which was carried out specifically in bowel cancer, could be relevant for other types of disease, particularly for cancers where surgery is not an option and radiotherapy is an important option, according to the researchers.