"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," the statement said. "With his usual strength of will, he has now chosen to discontinue medical treatment."
The statement said that in the past year of treatment, the 81-year-old McCain surpassed the expectations for his survival, but added that "the progress of the disease and the inexorable advance of age render their verdict."
The six-term US Senator was diagnosed with the rare and aggressive brain cancer in July of 2017 after doctors found a tumor while surgically removing a blood clot above his eye.
McCain was first elected to the US House of Representatives in 1982, and after two terms was elected to the US Senate in 1986, where he currently serves as the Chairman of the Senate Armed Services Committee. He also ran as the Republican Party's Presidential Nominee in 2008 against then-Senator Barack Obama.