John H. Glick, Specter's oncologist, said Specter "has an excellent chance of being completely cured of his Hodgkin's disease."
It is unclear what effect Specter's illness will have on the schedule of the Judiciary Committee. A hearing on the nominations of four federal judges is scheduled for March 1. Supreme Court Chief Justice William H. Rehnquist is ill with thyroid cancer and there has been speculation that he might step down and provide a vacancy on the high court.
The statement said that Specter had experienced persistent fevers and enlarged lymph nodes under his left arm and above his left clavicle, or collarbone. At Thomas Jefferson Hospital on Monday, Specter underwent biopsies of a lymph node and bone marrow.
"The lymph node was positive for Hodgkin's disease," the statement said. "The bone marrow biopsy showed no cancer.
"A follow up PET scan and MRI at the Abramson Cancer Center of the University of Pennsylvania yesterday established that Sen. Specter has stage IVB Hodgkin's disease," according to the statement.
Specter is expected to receive chemotherapy every two weeks over the next 24 to 32 weeks at the Abramson center.
Hodgkin's is a rare lymphoma, accounting for less than one percent of all cancer cases in this country. It can occur at any age but is most common among people aged 15 to 35 and adults over 50, according to the National Institutes of Health.
The disease usually spreads from lymph nodes in the neck, chest and armpits to the spleen, and then to the liver or nodes near the heart. In stage IV, the disease has spread outside the lymph system - for example, to the liver, bone marrow or lungs.
Patients are designated "A" if they have no symptoms, and "B" if they have lost 10 percent of body weight over the last six months or had unexplained fevers or night sweats.
The Abramson Cancer Center's Web site says the chance of recovery depends on the stage of the cancer, blood-test results, the patient's age, overall condition and other factors.
Glick, Specter's oncologist, said that the senator's form of the disease had a five-year survival rate of 70 percent.
"He is in superb physical condition, particularly in light of his daily squash regimen," said Glick, who is a professor of medicine at Penn and a nationally renowned expert in Hodgkin's disease.
With the disease widespread, the five-year survival rate is about 60 percent, according to the NIH.
A close friend of Specter's, Sen. Joseph R. Biden Jr. (D., Del.), spoke to Specter yesterday after the diagnosis.
"Dr. Glick has told Arlen that this is controllable and he can beat it," Biden said. "It's incredibly lousy news, but I think Arlen's in the best possible hands."
Biden said Specter sounded "optimistic but serious. He sounded good but also like a guy who'd gotten some bad news."
Specter, who this year will become Pennsylvania's longest-serving senator, survived a tough primary election against former Rep. Patrick J. Toomey and then defeated former Rep. Joseph M. Hoeffel 3d in the general election.
Following some postelection comments on abortion and judicial nominees that inflamed conservatives, Specter salvaged his committee chairmanship by convincing his colleagues that he would impose no litmus tests on abortion or any other issue on judicial nominees.
In his first weeks, Specter had shown that he wanted to run a tight ship. His hearings started on time and he shepherded through the nomination of Attorney General Alberto Gonzales. He also oversaw the panel's approval of legislation on class-action lawsuits.
One of those who backed Specter's chairmanship was the previous chairman, Orrin G. Hatch (R., Utah).
"I've known Arlen Specter for 25 years, and he has never shied away from a fight," Hatch said yesterday. "If anybody in his situation can beat this thing, it's Arlen. It's been my pleasure to have worked with one of the toughest men in the Senate and one of the best lawyers."
Specter's Pennsylvania colleague, Sen. Rick Santorum, said he was saddened by the news but said in a statement after speaking with Specter that "his spirits are up and he feels confident that he will get through this. He is in great shape to undergo treatment to battle this disease."
"My thoughts and prayers are with the Specter family during the days and months ahead as Arlen prepares for a speedy and complete recovery."
The ranking Democrat on the Judiciary Committee, Patrick J. Leahy of Vermont, said, "All of us who serve with Chairman Specter on the Judiciary Committee, Democrats and Republicans, regret that our friend is facing this new challenge." He added, "We look forward to Arlen feeling better and returning to the Senate."
Specter told close friends that he returned to Philadelphia from Washington last Thursday feeling feverish. He continued feeling poorly over the weekend and went to the hospital Monday for tests.
"Without a doubt, he will continue as judiciary chairman," said former chief of staff David Urban. "Now he'll work twice as hard, just to prove he can."
Contact reporter Steve Goldstein at 202-383-6048 or email@example.com.
Inquirer reporter Marie McCullough contributed to this article.