Radiation meets immunotherapy – a perfect match in the era of combination therapy?

Abstract

Purpose: This review focuses on recent advances in the field of combining radiation with immunotherapy for the treatment of malignant diseases, since various combinatorial cancer therapy approaches have lately proven highly successful.

Results: With initial case reports and anecdotes progressively converting into solid clinical data, interest in cancer immunotherapy (CIT) has risen steeply. Especially immune checkpoint blockade therapies have recently celebrated tremendous successes in the treatment of severe malignancies resistant to conventional treatment strategies. Nevertheless, the high variability of patient responses to CIT remains a major hurdle, clearly indicating an urgent need for improvement. It has been suggested that successful cancer therapy most probably involves combinatorial treatment approaches. Radiotherapy (RT) has been proposed as a powerful partner for CIT due to its broad spectrum of immune modulatory characteristics. Several preclinical studies, supported by an increasing number of clinical observations, have demonstrated synergistic interactions between RT and CIT resulting in significantly improved therapy outcomes.

Conclusions: Numerous reports have shown that radiation is capable of tipping the scales from tumor immune evasion to elimination in different tumor types. The next puzzle to be solved is the question of logistics – including types, schedule and dosage of combinatorial RT and CIT strategies.

Keywords::

• Radiation
• radiotherapy
• immunotherapy
• cancer
• combination therapy

Acknowledgements

The authors would like to acknowledge A. M. Dohnal (St Anna Children's Cancer Research Institute, Vienna, Austria) for critically reviewing the manuscript. The authors apologize to those colleagues whose studies were not cited in this review due to space limitations.

Funding

This study was supported by Department of Surgery, Massachusetts General Hospital (X.W.), NIH grant RO3 CA141086 (X.W.), the Austrian Science Funds (FWF) project P23271-B11 (K.S.) as well as the PhD program “BioToP – Biomolecular Technology of Proteins” (Austrian Science Funds, FWF project W1224) (K.S.).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.