Former Senate Democratic leader Harry Reid of Nevada. (Alex Brandon/AP)

Former Senate Democratic leader Harry M. Reid has been diagnosed with pancreatic cancer and underwent surgery Monday to remove the tumor, his family said. 

Reid, who led the Senate Democratic caucus for a dozen years until his retirement in early 2017, had the surgery at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University in Baltimore, and he plans to have chemotherapy treatments, according to a statement from his family Monday. 

“His doctors caught the problem early during a routine screening and his surgeons are confident that the surgery was a success and that the prognosis for his recovery is good,” the Reid family said. “He is now out of surgery, in good spirits and resting with his family. He is grateful to his highly skilled team of doctors and to all who have sent and continue to send their love and support.”

Reid, 78, who had represented Nevada in the Senate, has spent most of his time in retirement in Las Vegas and has traveled to Washington a handful of times, according to a person familiar with his travels. He, along with former House speaker John A. Boehner ­(R-Ohio), serves as a co-chair of the MGM Resorts International Public Policy Institute at the University of Nevada at Las Vegas, and he is a fellow at the university’s law school. 

The former majority leader announced that he would retire after three decades in the Senate in early 2015. Reid was succeeded in his Senate seat by Democrat Catherine Cortez Masto and as leader of Senate Democrats by Sen. Charles E. Schumer of New York. 

Schumer tweeted Monday afternoon that he has spoken to Reid’s family, and “it seems @SenatorReid’s operation went well. We are all praying for dear Harry’s speedy recovery.”

Later on the Senate floor, Schumer said Reid’s surgery “couldn’t have gone much better,” particularly considering the seriousness of pancreatic cancer.

Sen. John McCain (R-Ariz.), who was diagnosed with brain cancer last year and is being treated at home in Arizona, tweeted Monday: “From one cantankerous senator to another, sending my prayers & best wishes to @SenatorReid as he recovers from a successful surgery.”

“Senator Reid is no stranger to a fight. He beat his opponents in the boxing ring, took on the mob in Nevada and moved bills in the Senate that no one believed could be done,” Cortez Masto said. “He’ll beat cancer too. I wish him a speedy and successful recovery.”