Sen. John McCain's brain tumor is particularly aggressive type

WASHINGTON — Sen. John McCain's tumor is one of the most aggressive forms of brain cancer, and his family and doctors are deliberating next treatment options.The senator had undergone surgery last week to have a blood clot removed from above his left eye, and that clot turned out to be a sign that a tumor called a glioblastoma had begun growing.Here are some things to know:AGGRESSIVE CANCERMcCain's doctors at the Mayo Clinic said they managed to remove all of the tumor that was visible on