Radiotherapy and immunotherapy for cancer: From "systemic" to "multi-site".

Radiotherapy and immunotherapy for cancer: From "systemic" to "multi-site". Clin Cancer Res. 2020 Feb 11;: Authors: Arina A, Gutiontov SI, Weichselbaum RR Abstract In the era of cancer immunotherapy, there is a high interest in combining conventional cancer therapies such as radiotherapy with drugs that stimulate the immune system. The observation that ionizing radiation applied to mouse tumors could delay the growth of distant lesions ("abscopal effect") and this was potentiated by immunostimulatory drugs, led to clinical trials in which often only one lesion was irradiated. The results of these first clinical trials combining radio and immunotherapy are now becoming available. These results show that, while immunotherapy potentiates the local effects of radiotherapy, the abscopal effect is still infrequent. Transcriptomic analysis of resected colorectal cancer (CRC) metastases allows to distinguish three molecular subtypes with distinct potential to benefit from localized therapies and/or immunotherapy; the subtype with characteristics consistent with the existence of preexisting immunity is the most likely to respond to radiation. Recent preclinical data suggests these preexistent T cells can survive radiation and contribute to its therapeutic effect. In this review, we discuss possible reasons for the preclinical/clinical discrepancies regarding the abscopal effect, and we propose irradiation of multiple or all tumors combined wi...
Source: Clinical Cancer Research - Category: Cancer & Oncology Authors: Tags: Clin Cancer Res Source Type: research