Cancer is the leading cause of death in older adults aged 60 to 79 years. Older patients with good performance status are able to tolerate commonly used treatment modalities as well as younger patients, particularly when adequate supportive care is provided. For older patients who are able to tolerate curative treatment, options include surgery, radiation therapy (RT), chemotherapy, and targeted therapies. RT can be highly effective and well tolerated in carefully selected patients, and advanced age alone should not preclude the use of RT in older patients with cancer. Judicious application of advanced RT techniques that facilitate normal tissue sparing and reduce RT doses to organs at risk are important for all patients, and may help to assuage concerns about the risks of RT in older adults. These NCCN Guidelines Insights focus on the recent updates to the 2016 NCCN Guidelines for Older Adult Oncology specific to the use of RT in the management of older adults with cancer.