Senator Bob Casey, a Pennsylvania Democrat, Says He Has Prostate Cancer

Senator Bob Casey of Pennsylvania, who is part of Democrats’ razor-thin edge in the chamber and represents a swing state that has played an outsize role in the past two presidential elections, said on Thursday that he had prostate cancer but expected to make a full recovery.

Mr. Casey, 62, who is in his third term in the Senate, shared details about his recent diagnosis on Twitter, writing that the cancer was detected last month.

“While this news came as a shock, I can report that I have an excellent prognosis, as well as the benefit of exceptional medical care and the unwavering support of my family,” Mr. Casey wrote.

He will have surgery in the coming months, he added.

“I am confident that my recommended course of treatment will allow me to continue my service in the 118th Congress with minimal disruption, and I look forward to the work ahead,” he said.

He did not elaborate about how advanced the cancer was or disclose any types of additional treatment.

Democrats gained an outright majority in the Senate in November’s midterm elections, when they defied forecasts of a “red wave.” When Senator Kyrsten Sinema of Arizona decided last month to leave the party and become an independent, her move was not expected to alter the party’s power in the chamber.

Previously, the Senate had been split, with Democrats reliant on Vice President Kamala Harris to cast the tiebreaking vote.