WASHINGTON - One week after undergoing surgery to remove a malignant brain tumor, Senator Edward Kennedy, a leading liberal voice in the United States, was quietly released from a North Carolina hospital on Monday and was returning to his home in Hyannis Port, his aides said. Kennedy, 76, was released from Duke University Medical Center in Durham, North Caroline, where he had been recovering, apparently free of complications, for the past week. His doctors would not comment on his condition on Monday morning, but said he was "making an excellent recovery" and they were "pleased with his progress." "He will continue to recuperate at home before starting the next phase of his treatment," his aides said in a statement. Kennedy was given a diagnosis about three weeks ago of a malignant glioma in the left parietal lobe of his brain shortly after suffering a seizure at a family residence on Cape Cod. Malignant gliomas carry a bleak prognosis, particularly for someone of Mr. Kennedy's age and history, and at first it seemed that his doctors had ruled out surgery because of the risk of causing damage to his parietal lobe, an area involved in language and motor control. In interviews, brain surgeons said they sometimes opt not to operate in a case like Mr. Kennedy's because of the risk of damaging the patient's speech. But his doctors eventually decided it was the right option. And last week, they carefully sliced away as much of the cancer as possible in an operation that lasted just over three hours. In the coming days, his doctors have said, Mr. Kennedy will start targeted radiation and chemotherapy at Massachusetts General Hospital.