Republican U.S. Senator John McCain has chosen to discontinue medical treatment for an aggressive form of brain cancer, his family said in a statement on Friday, a year after the Vietnam War hero announced his prognosis.

"John has surpassed expectations for his survival," the family said, adding that the disease's progression and McCain's age, 81, had led him to stop treatment for the "aggressive glioblastoma." "With his usual strength of will, he has now chosen to discontinue medical treatment," the family said.

Full statement below:

"Last summer, Senator John McCain shared with Americans the news our family already knew: he had been diagnosed with an aggressive glioblastoma, and the prognosis was serious. In the year since, John has surpassed expectations for his survival. But the progress of disease and the inexorable advance of age render their verdict. With his usual strength of will, he has now chosen to discontinue medical treatment. Our family is immensely grateful for the support and kindness of all his caregivers over the last year, and for the continuing outpouring of concern and affection from John's many friends and associates, and the many thousands of people who are keeping him in their prayers. God bless and thank you all."

His daughter, Meghan McCain tweeted:

My family is deeply appreciative of all the love and generosity you have shown us during this past year. Thank you for all your continued support and prayers. We could not have made it this far without you - you've given us strength to carry on.

My family is deeply appreciative of all the love and generosity you have shown us during this past year. Thank you for all your continued support and prayers. We could not have made it this far without you - you've given us strength to carry on. pic.twitter.com/KuAQSASoa7 — Meghan McCain (@MeghanMcCain) August 24, 2018

We expect a Trump comment will follow shortly.