"The senator underwent surgery to remove a blood clot on Friday at Mayo Clinic Hospital in Phoenix. Lab results from that surgery confirmed the presence of brain cancer associated with the blood clot."
According to the doctor's statement, they only found a clot... since these clots can signal FUTURE cancer tumors, they biopsied tissue around that area... they found some early calls and removed them all before they could grow into tumors.
He'll be fine from this... they got to it before they could get to the tumor stage.