Oct. 25 (Bloomberg) -- U.S. Chief Justice William H. Rehnquist, who has presided over the Supreme Court since 1986, was hospitalized and treated for thyroid cancer.

Rehnquist, 80, underwent a tracheotomy Oct. 23 at the National Naval Medical Center in Bethesda, Maryland, the court said in a statement. He plans to be on the bench for the next public session, on Nov. 1, the court said.

More than 90 percent of those diagnosed with thyroid cancer survive, according to the American Cancer Society. Still, as the presidential campaign heads into its final days, Rehnquist's illness may renew questions about the future of the high court, where four justices are in their 70s or 80s.

``It's a poignant reminder that these people are nearing the end of their tenure, if not by choice then by the frailty of the human body,'' said Mary Cheh, George Washington University law professor. ``It seems to defy logic that there will be the same nine people in four years that there are now.''

In most cases, thyroid cancer isn't aggressive, doctors say. ``Thyroid cancer when diagnosed early and treated effectively is a disease from which almost all patients recover with no shortening of life span,'' said Paul Ladenson, director of the Johns Hopkins Thyroid Tumor Center and president of the American Thyroid Association.

The court's statement said Rehnquist underwent a tracheotomy, a procedure Ledenson said is used only in unusual cases. ``The need for a tracheotomy implies a very invasive and more severe form of cancer or a surgical complication,'' he said.

Rehnquist Votes

Supreme Court spokeswoman Kathy Arberg declined to provide details about Rehnquist's prognosis or treatment.

``My concern is that he has a more serious form of the cancer,'' said Herman Kattlove, an oncologist who serves as medical editor at the American Cancer Society.

Rehnquist was appointed to the high court by President Richard Nixon in 1972 and elevated to chief justice by President Ronald Reagan in 1986.

He has voted to limit the rights of accused criminals, permit abortion restrictions and curb the power of Congress. He favors restrictions on affirmative action and more power for states to erect religious displays.

Rehnquist was one of five Republican-appointed justices who halted the Florida ballot recounts that might have led to Democrat Al Gore's election over Bush in 2000.

Knee and Back Problems

The court hasn't had a vacancy in 10 years, the longest period of continuity since 1823. The future of the high court nonetheless has taken a backseat in the presidential campaign, overshadowed by Iraq, terrorism and the economy.

``The composition of the Supreme Court is as important as any issue in this campaign because judicial appointments last long beyond any president's term,'' said Erwin Chemerinsky, a Duke University law professor who has two cases before the court this term.

President George W. Bush was told about Rehnquist's condition early this morning, White House Press Secretary Scott McClellan said. ``The president and Mrs. Bush wish Chief Justice Rehnquist a speedy recovery,'' McClellan said.

David Wade, a spokesman for Democratic presidential nominee John Kerry, declined to comment.

Rehnquist had surgery in November 2002 to repair a knee tendon he tore in a fall at his home. He had back surgery in 1995 and still suffers from back problems that cause him to stand up and stretch during the court's arguments.

Rehnquist is due to be released from the hospital this week, the court said.

Three justices, in addition to Rehnquist, are cancer survivors: Sandra Day O'Connor, 74, John Paul Stevens, 84, and Ruth Bader Ginsburg, 71. Rehnquist is the court's second-oldest justice behind Stevens.

To contact the reporter on this story: Greg Stohr in Washington at gstohr@bloomberg.net.

Last Updated: October 25, 2004 15:39 EDT