Harnessing the Immunomodulatory Effects of Radiation in Urinary Bladder Cancer

The use of local radiation to elicit distant tumor response was proposed long back. The abscopal effect is regression of non-irradiated metastatic lesions at the distant site and there is an enormous therapeutic effect of immunomodulation. Radiation causes cancer cells to release antigens which mount an immune response, but this response is short lasting because cancer cells evade recognition by different mechanisms. Programmed Death Ligand-1 (PDL-1) pathway has been extensively studied. Combining immunotherapy and radiotherapy may result in long-term remissions especially for stage 4 cancer. Here we present a case of high grade urothelial carcinoma that progressed after four cycles of chemotherapy and after giving palliative radiation to urinary bladder he was started on nivolumab. First scan done after radiation and six cycles of nivolumab showed complete response. The patient continues to be in remission for the last 17 months from the start of radiation and immunotherapy that was started sequentially. Overall survival till date is 25 months.