Stereotactic radiosurgery (SRS) is a procedure that uses special equipment to position the patient and precisely deliver a large dose of radiation directly to a tumour, thus avoiding surrounding healthy tissue. This procedure does not use surgery. It is mostly used to treat brain tumours and other brain disorders. It is also being studied in the treatment of metastases from other types of cancer, such as kidney cancer, lung cancer and pancreatic cancer.
A study presented at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, USA last weekend discusses findings from an analysis of real world treatment outcomes in patients with brain metastases from renal cell carcinoma (RCC) treated with stereotactic radiosurgery and/or immunotherapy.
As kidney cancer treatment outcomes have improved, there has been an increasing incidence of brain metastases in patients with kidney cancer. Currently, kidney cancer ranks as the fourth most common cancer to spread to the brain, following lung cancer, breast cancer, and melanoma. Predicting the exact proportion of patients with kidney cancer who will develop brain metastases is estimated to be approximately 10% to 15% of those with stage IV disease.
Traditionally, treatment for patients with brain metastases was radiotherapy, either whole brain radiotherapy or focused radiotherapy, such as stereotactic radiosurgery. A large American database has shown that patients with RCC who were treated with both stereotactic radiosurgery and immunotherapy had the best outcomes, with an average overall survival time of 19 months compared with nearly 10 months in patients who received only stereotactic radiosurgery. This makes the combination of stereotactic radiosurgery and immunotherapy the preferred treatment for these patients.
Combining stereotactic radiosurgery with immunotherapy makes sense because radiation acts as a ‘sensitiser’ for immunotherapy and enhances the immune response. This combination has resulted better outcomes in patients than either treatment alone, a trend also observed in patients with lung cancer and melanoma brain metastases.