WASHINGTON – The chief justice of the United States, William Rehnquist, underwent thyroid cancer-related surgery Saturday but plans to return to the bench for oral arguments when the Supreme Court reconvenes Monday, the court announced.

In a brief statement released Monday, the court said doctors performed a tracheotomy on Rehnquist, 80, at National Naval Medical Center in suburban Bethesda, Md., “in connection with a recent diagnosis of thyroid cancer.”

Left unsaid was Rehnquist’s condition and which type of thyroid cancer he has. About 23,600 people develop various types of thyroid cancer each year in the United States. Most types are considered treatable, but many variables exist, including age and how quickly the cancer is found.

The thyroid is a gland near the base of the throat that helps to regulate body temperature and metabolism, as well as to maintain normal functioning of the heart and brain. Tumors in the thyroid can invade the windpipe, or trachea. Generally, doctors use a tracheotomy – a small hole in the neck that permits air to enter the windpipe directly from the outside – in cases where, for any reason, a patient has no other way to get air.

The hole in the throat created by a tracheotomy is permanent. But once a patient is able to breathe normally again, the opening is closed by a small plastic plug so the patient can speak.

The news that the chief justice has a potentially life-threatening condition threw into doubt the stability of a court whose membership last changed in 1994.

The next president probably will name one or more justices to a court that has been deeply divided in recent years on issues as varied as abortion and the 2000 election itself. President Bush won that after the Supreme Court issued a key 5-4 decision in his favor, with Rehnquist as part of the majority.

Justices’ health

Health conditions of the current Supreme Court justices:

William H. Rehnquist, 80: Thyroid cancer; had surgery for a torn tendon in 2002 and missed several court sessions after hurting his knee in a fall at home; chronic back pain that has required physical therapy.

John Paul Stevens, 84: Treated for prostate cancer in 1992; also battled heart disease but said to be in general good health recently.

Sandra Day O’Connor, 74: Bout with breast cancer in 1988 but appears to have recovered.

Antonin Scalia, 68: Had shoulder surgery last year to repair a torn rotator cuff; said to be in overall good health.

Anthony M. Kennedy, 68: Had cataract surgery in 1997 but vision now excellent; no apparent health problems.

David H. Souter, 65: No apparent health problems.

Clarence Thomas, 56: No apparent health problems.

Ruth Bader Ginsburg, 71: Treated for colon cancer in 2000 but appears to have recovered.

Stephen G. Breyer, 66: No apparent health problems.

Associated Press