Two clinical trials looking at the use of radiotherapy and immunotherapy for metastatic renal cell carcinoma (RCC) were presented at the American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium in San Francisco last weekend.
First was the Phase II NIVES trial. In this trial, advanced kidney cancer patients who had been treated with targeted therapy were treated with the immunotherapy drug nivolumab and focused radiation (stereotactic body radiotherapy, SBRT). Radiation appeared safe with the immunotherapy, but people in the trial did not seem to benefit more than past studies of immunotherapy alone.
The second trial was the RADVAX RCC trial, which combined two immunotherapy drugs (nivolumab and ipilimumab) with focused radiation (SBRT) in patients with advanced kidney cancer. The benefit of adding focused radiation to the two immunotherapy drugs seemed at least equal to past studies where patients were treated with a combination of the two immunotherapy drugs, and appeared safe.
Both these clinical trials enrolled small numbers of patients. In both trials, radiation was given to only 1-2 spots of cancer. These trials do not support immediate use of radiation with immunotherapy in people with kidney cancer, but they show that if radiation is needed, it is safe when taking immunotherapy. One situation where this might be useful is if one tumour starts to grow, while other spots of the cancer are shrinking due to immunotherapy treatment; “hunting down tumours that escape” seems like an attractive and sensible idea. Future trials will tell us if there are better ways of improving the benefit of immunotherapy in combination with radiation.