WASHINGTON, Aug. 24 (Xinhua) -- John McCain, 2008 Republican presidential nominee and six-term U.S. senator, has chosen to discontinue medical treatment for a fatal type of brain cancer, his office said in a statement Friday.

The chairman of the Senate Armed Services Committee has been battling the cancer called glioblastoma since last summer.

"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. "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 said.

Local reports said McCain has been absent from the Capitol Hill since December but continued his Senate duties as much as he could from his family home in northern Arizona, 2,200 miles away from Washington, D.C. However, he could not cast Senate votes by proxy or in absentia.

McCain will turn 82 years old on Aug. 29.