Democratic congressional nominee David Trone in January, before his cancer diagnosis. (Ricky Carioti/The Washington Post)

David Trone, the Potomac Democrat who is running for Congress, announced Monday that he is being treated for cancer and that he will continue his campaign to succeed Rep. John Delaney (D-Md.).

Trone, co-founder of Total Wine & More, has undergone chemotherapy and is scheduled for surgery in mid-September to remove a kidney. He said he plans to return to the campaign trail quickly and is confident he will make a full recovery.

“Nothing will interfere with my being fully engaged as a candidate and as a member of Congress after the recovery,” Trone, 62, said in a statement released by his campaign.

Trone spent $10 million of his own money on his way to winning the Democratic nomination in June, defeating seven opponents in a gerrymandered 6th Congressional District that stretches from the Washington suburbs to western Maryland.

He faces Republican Amie Hoeber in the Nov. 6 general election, a race that political forecasters expect him to win.

Delaney is vacating the seat to run for president.

Trone’s campaign is his second for Congress. In 2016, he spent $13 million of his own money while losing the Democratic nomination for the 8th District seat now held by Rep. Jamie B. Raskin. Trone and his family have been major donors to Democrats and Republicans in Maryland and throughout the country.

The decision to reveal his diagnosis came three days after a political blogger published photos of Trone with thinning hair and appearing as though he had lost weight. The post in A Miner Detail said Maryland Democratic officials were concerned about Trone’s health and quoted Trone campaign manager Jerid Kurtz dismissing the speculation as “gossip.”

But with rumors mounting over the weekend, Trone’s campaign released its statement late Monday afternoon. It said that on June 25 — the day before he won the Democratic primary — lab tests confirmed that Trone had a “tumor in my urinary tract.”

The candidate did not immediately reveal his medical condition to senior campaign advisers. He displayed no outward sign that his health was suffering when he showed up for his victory party the following night.

“Since then, I have undergone treatment at Johns Hopkins in Baltimore that has led to a substantial reduction in the size of the tumor,” Trone said in the statement.

He was not available for an interview Monday.

The news release included a statement from Trone’s doctor, Phillip Pierorazio, who described the candidate’s prognosis as “excellent.”

“We expect David to fully recover, to return as an active candidate, and, if elected, to carry out all of the duties of a member of the House of Representatives,” Pierorazio said.

Trone is at least the second Maryland politician to publicly battle cancer in recent years. Gov. Larry Hogan (R) announced in 2015 that he had been diagnosed with a “very advanced and very aggressive” form of cancer — late Stage 3 non-Hodgkin’s lymphoma.

The governor, who is vying with Democrat Ben Jealous for a second term, recovered and has been an advocate for people with cancer since his diagnosis.

Aides said Trone is expected to appear in public in the coming days, including at a Maryland Democratic Party fundraiser next week. Rep. Kyrsten Sinema (D-Ariz.) is scheduled to participate with Trone in a Rockville meet-and-greet.

In his statement, Trone included laudatory quotes from an array of Maryland elected officials, including Delaney, Sens. Benjamin L. Cardin (D-Maryland) and Chris Van Hollen (D-Maryland) and Raskin.

A cancer survivor himself, Raskin said that he knows “how tough this is going to be” for Trone and his wife, June. “But I also know he’s tough as nails,” Raskin said.

Jealous issued his own statement, calling Trone “a fighter” and saying, “My prayers are with David and his family during this difficult time.”