Sen. John McCain has stopped medical treatment for brain cancer, his family said in a Friday statement. “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,” the statement declared. “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.” McCain, 81, has served as a Republican senator from Arizona since 1987, when he replaced Barry Goldwater.