BOSTON -- Sen. Edward M. Kennedy was released from the hospital Wednesday and was heading to his Cape Cod home one day after being diagnosed with a cancerous brain tumor that experts say is almost certainly fatal.

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The 76-year-old Kennedy waved to a crowd of well-wishers and gave a thumbs-up as he walked out of Massachusetts General Hospital amid heavy security. His dogs greeted him at the hospital door.

Doctors said Wednesday that the Massachusetts Democrat "has recovered remarkably quickly" from a biopsy conducted after he suffered a seizure last weekend at his home on Cape Cod.

Kennedy will recuperate at home while the doctors await further test results and determine his treatment plan.

Kennedy has a malignant glioma in his left parietal lobe.

Malignant gliomas are diagnosed in about 9,000 Americans a year; in general, half of all patients die within a year.

A neurosurgeon at Cedars-Sinai Medical Center said, considering the senator's age, Kennedy may have a survival of less than a year.

Kennedy's wife, Vicki, said earlier that the diagnosis that the Massachusetts senator has a cancerous brain tumor has pitched the family "a real curveball."

But in an e-mail to friends, she wrote, "This is only the first inning."

Kennedy's doctors said tests conducted after Kennedy suffered the seizure showed the tumor. His treatment will be decided after more tests, but the usual course includes combinations of radiation and chemotherapy. The doctors mention these treatments but, ominously, do not mention surgery. That's taken as a sign that the tumor may be inoperable.

Scientists are studying new approaches to fighting the deadly cancer, such as brewing up customized vaccines to help the body fight back.

Glioma experts advise newly diagnosed patients to seek out specialized cancer centers and ask if they're a good candidate for a research study up front.

Vicki Kennedy said the family is seeking multiple opinions from specialists. She also said Kennedy himself is leading them all with "his calm approach to getting the best information possible."

She said he's even been pushing to take part in a Cape Cod sailing race this weekend.