Former U.S. Senator Arlen Specter, who has already survived two bouts of Hodgkin's disease, is now battling non-Hodgkin's lymphoma, according to his son's law firm.
A statement released Friday said Mr. Specter had been released from a Philadelphia hospital but was expected to return there for additional treatment.
Mr. Specter said in a statement last week that he was again fighting cancer.
"It's another battle I intend to win," Mr. Specter wrote. "I'm grateful for all the well wishes I've received."
Mr. Specter, who was Pennsylvania's longest-serving senator before losing a primary in 2010, has overcome two bouts with Hodgkin's disease, a cancer of the lymphatic system, since 2005. He also has survived a brain tumor and cardiac arrest after bypass surgery.
Non-Hodgkin's lymphoma is broad description for a number of blood cancers primarily affecting white blood cells in the lymph tissue. It can be treated with radiation or chemotherapy.
Ms. Specter's 30-year Senate career ended after he switched from the Republican Party to the Democratic Party and lost the subsequent primary. Later that year, Pennsylvania voters elected conservative Republican Pat Toomey, then a congressman, to replace him.